Neurospora mutants beginning with T

Translocation D305
Thiamine (thi)
Chromosome Tips
Tryptophan (trp)
Tyrosine (tyr)

t: thermophobic See scot.

T: tyrosinase
IR. Between ad-3A (18%) and al-2 (474).

Tyrosinase structural gene (Fig. 11). Prototrophic. Multiple alleles distinguished electrophoretically and by thermolability (473-477). Null allele not known. Primary structure (407 amino acids) determined for the product of allele TL (599). Scored by color reaction with DL-3,4- dihydroxyphenylalanine as a substrate (475, 477). Two forms of enzyme demonstrated in heterokaryons (474). For regulation, see references 332, 472, and 475 and references therein. Also see tyrosinase regulatory genes, symbolized ty.

T: (used as prefix to allele [isolation] numbers)
Has been used in allele numbers for mutants isolated at the Universities of Tokyo and Texas.

T( ): translocation
Translocations are listed here only if they were used for mapping genes, centromeres, or chromosome tips. They can often be used for mapping by duplication coverage (analogous to deletion mapping in phages and other organisms). When an insertional or terminal translocation is crossed by normal sequence, independent segregation produces recombinant meiotic products that are duplicated for the translocated segment. Such a translocation involving linkage groups D (donor) and R (recipient) is symbolized T(D->R). Crosses between two different reciprocal translocations that have breakpoints in the same two chromosome arms can produce recombinant meiotic products duplicated for segments between the displaced breakpoints. Simple reciprocal translocations involving linkage groups B and C are symbolized T(B;C). For theory, diagrams, methods, review, and description of many additional translocations, see reference 808. Translocations listed as terminal are thought to be really quasiterminal, i.e., reciprocal translocations in which one breakpoint is very close to a tip and distal to all essential genes.

T(AR18): insertional translocation T(IIL->IIIR)AR18
An interstitial segment of IIL is inserted in IIIR. Viable duplication progeny from T x normal sequence contain two copies of the segment, which includes het-6 but not cys-3, het-c, or pyr-4 (729, 808).

T(AR30): reciprocal translocation T(IIL;VL)AR30
A distal segment of IIL, with breakpoint mapping left of pi (30% recombination), is interchanged with a distal segment of VL, with breakpoint between NO and caf-1 (19%) (600, 808, 817).

T(AR33): terminal translocation T(VL->IVL)AR33
A distal segment of VL is translocated to the left tip of IV. Viable duplication progeny from T x normal sequence contain two copies of the segment, which includes the nucleolus organizer and caf-1 but not lys-1 or at (808, 817). Used to demonstrate demagnification of genes specifying rRNA (887).

T(T39M777): terminal translocation T(VIL->IR)T39M777
A distal segment of VIL is translocated to the right tip of I. Viable duplication progeny from T x normal sequence contain two copies of the segment, which includes un-4 and markers distal to it, but does not include cys-1 (808).

T(T54M50): terminal translocation T(VIIL->IVR)T54M50
A distal segment of VIIL is translocated to the right tip of IV. Viable duplication progeny from T x normal sequence contain two copies of the segment, which includes thi-3 and csp-2 but not met-7 (808).

T(STL76): reciprocal translocation T(IR;IIR)STL76
A distal segment of IL with a breakpoint between cyh-1 and os-5 is interchanged with IIR between arg-12 and ace-1. When translocation T(STL76) is crossed with overlapping translocation T(4637), viable duplication progeny result that contain two copies of the intervals between breakpoints of the two translocations. See T(4637) for included markers (808).

T(NM103): terminal translocation T(IR->VIR)NM103
A distal segment of IR is translocated to the right tip of VI. Viable duplication progeny from T x normal sequence contain two copies of the segment, which includes met-6 and markers distal to it, but does not include thi-1 (808, 1091).

T(NM149): terminal translocation T(IIL->VR)NM149
A long segment of IIL is translocated to the right tip of V. Viable duplication progeny from T x normal sequence contain two copies of the segment, which includes ro-3 but not thr-2, thr-3, or tng (808, PB).

T(NM152): insertional translocation T(IVR->I)NM152
An interstitial segment of IVR is inserted in I. Viable duplication progeny from T x normal sequence contain two copies of the segment, which includes pyr-3 through pyr-2 and mat, but does not include arg-14 or cys-4 (238, 745, 808).

T(ALS159): terminal translocation T(IVR->VIR)ALS159
A distal segment of IVR is translocated to the right tip of VI. Viable duplication progeny from T x normal sequence contain two copies of the segment, which includes pyr-1 and all IVR markers distal to it, but does not include psi (745, 908).

T(NM169d): terminal translocation T(IR->VL)NM169d
A distal segment of IR is translocated to the left end of V. Viable duplication progeny from T X normal sequence contain two copies of the segment, which includes un-18 but not R (808, PB; B.C. Turner, personal communication).

T(AR173): complex duplication-generating translocation T(IR,IR;V;VII)AR173
An interstitial segment of IR behaves as though inserted in V or VII. Viable duplication progeny from T x normal sequence contain two copies of the segment, which includes un-2, cyt-4, and his-2 but not sn, nuc-1, or rg-1 (670, 808).

T(ALS176): terminal translocation T(IIR->VL)ALS176
All or most of IIR is translocated to the left tip of V (nucleolus satellite). Viable duplication progeny from T x normal sequence contain two copies of the IIR segment, which includes arg-5 and all markers distal to it, but does not include bal (808, 809).

T(NM177): insertional translocation T(IIR->IL)NM177
An interstitial segment of IIR is inserted in IL. Viable duplication progeny from T x normal sequence contain two copies of the segment, which contains nuc-2 through arg-12, but does not include aro-3 or the aro cluster gene (671, 808; A. Kruszewska, personal communication).

T(ALS179): translocation T(VIIL->IVR)ALS179 (probably terminal)
A far-left segment of VIIL is translocated to the right end of IV. Viable duplication progeny from T x normal sequence are inferred to contain two copies of the segment, which includes no known genic markers (808).

T(AR179): complex duplication-generating translocation T(IIL;IIL;IVR;VL)AR179
A long segment of IIL is duplicated in one class of progeny from T x normal sequence. The segment includes thr-2 and markers distal to it, but does not include bal or arg-5 (808).

T(ALS182): terminal translocation T(IR->VL)ALS182
A distal segment of IR is translocated to the left tip of V (nucleolus satellite). Viable duplication progeny from T x normal sequence contain two copies of the segment, which includes met-6 and markers distal to it, but does not include thi-1 (670, 809).

T(AR190): terminal translocation T(IR->VL)AR190
Most of IR is translocated to the nucleolus satellite at the left tip of V. Viable duplication progeny from T x normal sequence contain two copies of the segment, which includes his-2 and markers distal to it, but does not include un-2 (670, 808).

T(AR209): terminal translocation T(VIR->IVR)AR209
All or most of VIR is translocated to the right tip of IV. Viable duplication progeny from T x normal sequence contain two copies of the segment, which includes pan-2 and probably rib-1, but does not include ad-1 or ylo-1 (808).

T(D305): complex duplication-generating translocation T(IIIR;IIIR;VIL;X?)D305
A distal segment of IIIR is duplicated in one class of progeny from T x normal sequence. These duplication progeny contain two copies of the segment, which includes phe-2 and dow but not ro-2 (808, 809).

T(OY320): terminal translocation T(VIR->IIIR)OY320
A distal segment of VIR is translocated to the right tip of III. Viable duplication progeny T x normal sequence contain two copies of the segment, which includes ws-1 but not trp-2 (808).

T(OY321): nearly terminal translocation T(IL->VL)OY321
A distal segment of IL is translocated to the nucleolus organizer in VL. Viable duplication progeny from T x normal sequence contain two copies of the segment, which includes cyt-1 and markers distal to it, but does not include leu-4. The viable duplications contain only the proximal portion of the nucleolus organizer (808; D.D. Perkins, N.B. Raju, and E.G. Barry, in preparation).

T(S1229): insertional translocation T(IVR->VII;IL;IIR;IVR)S1229 arg-14
An interstitial segment of IVR is inserted in VII. The right breakpoint in IV is inseparable from arg-14. Viable duplication progeny from T x normal sequence contain two copies of the segment, which includes pt, cys-15, and mtr through arg-2, but does not include pdx-1 or pyr-3. (Reference 238 is incorrect in showing pdx-1 included.) (54, 55, 238, 808).

T(P2869): insertional translocation T(IIL->VI)P2869
An interstitial segment of IIL is inserted in VI. Viable duplication progeny from T x normal sequence contain two copies of the segment, which includes ro-7, pi, and het-6 but not het-c or pyr-4 (808).

T(S4342): insertional translocation T(IVR->IIIR)S4342
An interstitial segment of IVR is inserted in IIIR. Viable duplication progeny from T x normal sequence contain two copies of the segment, which includes arg-14 through uvs-2, but does not include arg-2 (238, 808).

T(4540): insertional translocation T(IR->IIIR)4540 nic-2
An interstitial segment of IR is inserted in IIIR. The left IR breakpoint is inseparable from nic-2. Viable duplication progeny from T x normal sequence contain two copies of the segment, which includes cr-1, cys-9, and un-1 but not ad-3B or thi-1 (808, 908).

T(4637): reciprocal translocation T(IR;IIR)4637 al-1
A distal segment of IR with breakpoint at al-1 is interchanged with IIR (left of arg-12). When T(4637) is crossed with overlapping translocation T(STL76), viable duplication progeny result that contain two copies of the intervals between breakpoints of the two translocations. The duplicated segment includes IR markers un-7 and os-5 through hom but does not include cyh-1 or lys-3 (808; D.D. Perkins, unpublished data).

T(5936): terminal translocation T(VIIR->IL)5936
A distal segment of VIIR is translocated to the left tip of I. Viable duplication progeny from T x normal sequence contain two copies of the segment, which includes arg-11 and markers distal to it, but does not include dr (808, PB).

T(39311): insertional translocation T(IL->IIR)39311
An interstitial segment of IL is inserted in IIR. Viable duplication progeny from T x normal sequence contain two copies of the segment, which includes nit-2 through csp-1 but does not include un-5, sn, or os-4 (798, 808, 809).

ta: tufted aerial
IL. Between un-16 (2%) and acr-3 (< 3%) (816, PB). Rapid-spreading colonies. Morphology is distinguishable from that of the wild type, but varies with growth conditions (816). Conidiation best at 34°C. Possible maternal effect, with ta+ sometimes resembling ta in initial cultures from ascospores. (D. Newmeyer, unpublished data).

td: tryptophan desmolase (synthetase)
See trp-3.

tet: tetrazolium
IL. Right of mating type (7 to 8%). Linked to acr-3 (2%) and ad-3B (1%) (395).

Tetrazolium dye reduction. Detected as a difference between A and a laboratory strains (74-OR23-1A colonies fail to reduce dye and thus remain white; 74-OR8-1a colonies reduce dye to red) (395). Called Tet-R and Tet-W ("red," "white"). See reference 395 for tests on other wild types. cya, cyb, and cyt mutants all fail to reduce 2,3,5-triphenyl-tetrazolium chloride, and this is used as a test in the initial identification of such mutants. cya-1, cyt-3, and cyt-4 are all located near the mating type locus (87); their relationship to tet is not known. Probably (but not certainly) the same gene is responsible for the mating-type-linked difference in resistance to 2,3,5-triphenyl-tetrazolium chloride. 2,3,5-triphenyl-tetrazolium chloride-resistant strains include 74-OR23-1A, Em A FGSC no. 691, Em A 5256, Lindegren 1A, Lindegren 25a, and all RL wild types tested. 2,3,5-Triphenyl-tetrazolium-sensitive strains include 74-OR8-1a, Em a FGSC no. 692, and Em a 5297 (1116, 1117). Oak Ridge a wild-type strain ORSa, derived by backcrossing to 74-OR23-1A, is resistant (731). The gene for 2,3,5-triphenyltetrazolium chloride resistance maps left of mei-3, probably between mt and arg-1 (D.R. Galeazzi, personal communication).

thi-1: thiamine-1
IR. Right of the T(4540) right breakpoint and cys-9 (13%). Left of T(NM103), T(ALS182), and met-6 (7 to 14%) (721, 808, 816, 1091). (482).

Uses thiamine or precursors pyrimidine plus thiazole (1059). Adaptation to growth on minimal medium occurs after a lag; growth tests should, therefore, be scored early. Adaptation is not carried over via ascospores, conidia, or small mycelial fragments. Adaptive growth is paralleled by attainment of wild-type thiamine pyrophosphate and carboxylase levels. Apparently concerns utilization of intact thiamine rather than its biosynthesis. (302, 303). Allele 17084 is inseparable from translocation T(IR;VII)17084 (808).

thi-2: thiamine-2
IIIR. Between his-7 (1 to 2%) and ad-2 (1 to 3%) (219, 814). (504).

Requires thiamine. Cannot use pyrilmidine plus thiazole (1059). Does not undergo growth adaptation on minimal medium (302).

thi-3: thiamine-3
VIIL. Between nic-3 (9 to 18%) and T(T54M50) (808, 812, 816). (482).

Uses thiamine or thiazole (1059). Does not undergo growth adaptation on minimal medium. Growth on minimal medium is leaky at first, but becomes tight with exhaustion of endogenous thiazole (302), so scoring is best done late.

thi-4: thiamine-4
III. Linked to acr-2, spg, and sc (< 1%). Left of pro-1 (3%) and ace-2 (4 to 9%) (812). (482).

Requires thiamine (301). Anomalous in condensation of the pyrimidine and thiazole precursors. Very leaky (301). A probable allele called "thi-lo" greatly increases the thiamine requirement of thi-1 strains and decreases the ability to synthesize thiamine from pyrimidine and thiazole. thi-lo strains have no detectable nutritional requirement in the absence of thi-1. thi-lo failed to recombine with thi-4 among 55 scorable progeny (301).

thi-5: thiamine-5
IVR. Linked to pan-1 (19%) (812).

Uses thiamine (482). Probably 2-methyl-4amino-5-aminomethyl pyrimidine can also be used (799).

thi-lo: thiamine-low
See thi-4.

thr-1: threonine-1
Name changed to ile-1, q.v. Because this locus specifies threonine dehydratase, the original name thr-1 is inappropriate (549, 552). See Fig. 15. Called thre-1 in reference 240.

thr-2: threonine-2
IIL. Right of T(NM149) and ro-3 (6 to 25%). Left of T(AR179); hence, left of bal and arg-5 (3 to 18%). Adjoins thr-3 (< 0.1%) (808, 812, PB).

Requires threonine. Cannot use other amino acids (1061). Lacks threonine synthetase (352) (Fig. 17). Strongly inhibited by methionine (320, 1061). Known alleles are not heat sensitive, unlike all known thr-3 alleles.

thr-3: threonine-3
IIL. Linked to thr-2 (< 0.1%) (812).

Requires threonine. Also responds slightly to alpha-aminobutyric acid or isoleucine. Known alleles are heat sensitive (25°C versus 34 C), requirement is tight at 34°C. Not inhibited by methionine (320, 1061).

ti: tiny
IL. Between arg-3 (1%) and the T(39311) right breakpoint (PB) (789).

Heat sensitive. Spreading colonial morphology at 25°C or below; more restricted at 30°C; no growth at 34°C (789, PB). Can be scored microscopically after ascospore germination. Reduced amount of cell wall peptides (1165).

timex
Symbol formerly used to designate bd;inv double mutants. See bd.

Tip: (chromosome tip)
Eight chromosome tips have been defined by mapping the breakpoints of terminal translocations relative to gene loci. Because a class of meiotic segregants from these translocations are viable that would necessarily be deficient for any chromosomal segment distal to the terminal breakpoint, it is known that no essential gene loci are located beyond the site of translocation. Although these rearrangements behave genetically as terminal, they are thought to be reciprocal translocations in which the telomere is translocated. They would, therefore, more accurately be called quasiterminal. See references 467, 756, and 808. The VL tip has also been mapped by an independent method, using the heteromorphic satellite as a terminal cytological marker. Remaining tips are simply listed as located beyond the most distal known gene marker.

Tip IL: left tip of linkage group I
Marked by terminal translocation T(5936), which is linked to ro-10 (0/38) and fr (11%) (808, PB).

Tip IR: right tip of linkage group I
Marked by terminal rearrangements In(NM176), In(H4250), and T(T39M777), which are closely linked to R and un-18 (808, 1093; H.R. Cameron, personal communication).

Tip IIL
Left of T(AR30), which is left of pi (~30%) (600). An extended unmarked segment left of pi is also suggested by data from T(NM149) (D.D. Perkins, unpublished data).

Tip IIR
Right of rip-1 and un-15.

Tip IIIL
Left of r(Sk-2)-1, cum, acr-7, acr-2, and thi-4.

Tip IIIR
Marked by T(OY320), which is linked to dow (6%) (PB).

Tip IVL
Marked by T(AR33), which is linked to cys-10 (0/221) and left of acon-3 (< 1%) (817, PB).

Tip IVR
Marked by T(AR209), T(T54M50), and T(ALS179), which are right of uvs-2 (2 to 6%) and cys-4 (817).

Tip VL
Marked by sat, T(ALS176), T(ALS182), and T(AR190), which are left of T(AR30), caf-1 (>11%), and lys-1 (20 to 35%) (60, 600, 808, PB).

Tip VR
Marked by T(NM149), which is linked to his-6 (0/499) (808; D.D. Perkins, unpublished data).

Tip VIL
Left of chol-2.

Tip VIR
Marked by T(NM103) and T(ALS159), which are right of trp-2 (13%) (808, 1091; D. D. Perkins, unpublished data). Right of ws-1 and un-23.

Tip VIIL
Left of T(ALS179), het-e, and su([mi-1])-5.

Tip VIIR
Right of sk.

tng: tangerine
II. Right of T(NM149) and pyr-4 (16%). Left of arg-5 (6 to 14%) and probably left of thr-2 (2%) (PB).

Irregular spreading growth. Hyphae not curled (unlike ro), and not as densely branched as col-4. Conidia formed in irregular patches. Many conidia are large, with 5 to 20 nuclei (allele P4474) (N.B. Raju, personal communication). Resembles ro-9 (R2526) strains in gross appearance, and the genes map in similar locations. Both are female infertile. (PB).

tol: tolerant
IVR. Linked to trp-4 (~1%), probably to the left (755).

Suppresses the vegetative (heterokaryon) incompatibility associated with mating type alleles A and a, but does not affect sexual compatibility. (tol;A + tol;a) heterokaryons are fully compatible and stable if other het loci are homokaryotic, and A/a duplications grow normally when tol is present (755). Recessive (252); see reference 746, however, for a stable mixed-mating type heterokaryon that is (tol a + tol+ slime A). tol does not suppress the vegetative incompatibility of differing alleles at het-c or het-e (755, 803). Mutation or deletion of tol+ restores normal growth rate to slow-growing, unstable, mixed-mating-type (tol a + tol+ A) heterokaryons (252). tol is present in some isolates from nature and has arisen at least twice by mutation in laboratory stocks (755, PB; O.C. Yoder, personal communication). Double-mutant tol trp-4 stocks are convenient because the closely linked trp-4 tags the tol allele, which otherwise requires progeny tests for scoring. Used to maintain stable A + a heterokaryons, allowing the desired component to be used as the parent in a cross (746). Homozygous tol may partially restore fertility to the mutant fmf-1 (531).

Tp( ): transposition
Used to designate rearrangements having a segment transposed from one interstitial position to another in the same chromosome. In crosses of Tp by normal sequence, crossing over in the segment between the two positions can generate recombinant meiotic products that are duplicated for the transposed segment. These can be used for mapping by duplication coverage (808).

Tp(T54M94): transposition T(IR->IR)T54M94
An interstitial segment of IR is transposed proximally and inserted in inverted order. Viable duplication progeny produced by crossing over in crosses of Tp x normal sequence include nit-1 through al-2, but do not include ad-9 or arg-6 (808, 809; B.C. Turner, personal communication).

tru: transport of uracil
See uc-5.

Transport mutants
Mutations affecting transport have been obtained by many techniques, using metabolites, antimetabolites, etc. Nomenclature has consequently been chaotic. Transport mutations are listed under the following entries.

(i) Amino acid transport: Basic (pmb, = bat); neutral (mtr, = pmn); and general [pmg; see also su(mtr)-1]. Individual genes have been symbolized (e.g., references 248 and 1152) as pm b or Pm- B, and compound mutants, such as pmn;pmb, have been symbolized pm nb or Pm- NB. Symbols in the present article are changed from this nomenclature so as to show that pmn and pmb are separate genes. Other mutant genes that may involve amino acid transport are argR, lysR, hlp-1, and hlp-2.

(ii) Transport or possible transport mutations for other metabolites or ions: acpi, car, cys-13, cys-14, fpr, glt, ipm-1, ipm-2, mea-1, sit, sor, trk, tys, uc-5, and ud-1.

(iii) Mutations that appear to affect more than one transport system: hgu-4, nap, fpr-6, mod-5, mts, and un-3; see especially reference 1149.

(iv) There are also general regulatory loci that control many related enzymes including the relevant permeases, e.g., nit-2, cys-3, pcon (nuc-2), preg, pgov, and nuc-1. Transport of various ions and compounds is reviewed in references 406 and 921; amino acid transport is reviewed in reference 1150, and peptide transport is reviewed in reference 1151.

tre: trehalase
IR. Between met-6 (7%) and al-2 (20 to 37%); near mig (< < 1%) (1045, 1176). Shown between met-6 and ad-9 (7%) in reference 466, with only two-point data given.

Unable to use trehalose as carbon source. Lacks trehalase activity. (Also, the invertase level is reduced 50% and the amylase level is increased.) In (tre + tre+) heterokaryons, the trehalase level is reduced to 10% of the wildtype level, and in tre/tre+ duplications the level is reduced to 1% of the wild-type level. tre codes for trehalase inhibitor, probably a protein (1045). For a possibly related regulatory mutation, see reference 663. For putative structural gene, see mig.

trk: transport of potassium
IIIR. Linked to leu-1 (0/92) (988).

Requires high K+ concentration for growth. Na+ cannot substitute. Cation transport system maximum velocity is normal; Km is three times normal. Recessive. Obtained by inositol death enrichment on low potassium. (988)

tRNA synthetase
See leu-5 and trp-5.

trp: tryptophan
Tryptophan is required in much higher concentrations than its precursors, anthranilic acid and indole. A 0.01-mg/ml amount of the precursor is sufficient, but up to 0.1 or 0.2 mg of tryptophan per ml is required by some mutants. High concentrations of anthranilic acid are toxic. Most trp mutants grow better on 0.2 mg of tryptophan per ml plus 0.2 mg of phenylalanine per ml than on tryptophan alone. For the biosynthetic pathway, see Fig. 11. Also called tryp and try. trp-3 called td. See also nt.

Tryptophan feedback inhibits anthranilate synthase, anthranilate phosphoribosyltransferase, and one of three isozymes of 3-deoxy-D-arabinoheptulosonic acid-7-phosphate synthase (the first step in aromatic biosynthesis). Tryptophan stimulates chorismate mutase, directing chorismate to prephenate rather than to anthranilate synthesis. All four genes of the tryptophan pathway are derepressed by starvation for tryptophan. High indoleglycerol-phosphate levels also cause derepression. Derepression may involve inhibition of Trp-tRNA synthetase. (40, 152, 258, 436, 603, 742, 1004, and references therein). Genes for tryptophan biosynthesis are derepressed coordinately with those for histidine, arginine, and lysine biosynthesis; this is called "cross-pathway regulation" (137, 1131); reviewed in reference 642; see cpc-1.

trp-1: tryptophan-1
IIIR. Between ad-2 (1 to 7%) and ro-2 (2 to 12%) (11, 219, 812). Linked to fpr-3 (< 1%) (550). (504).

Uses tryptophan or indole (1060); strains carrying some alleles can also use anthranilate; others cannot (4). trp-1+ and trp-2+ gene products together form an enzyme aggregate with three activities: anthranilate synthetase, phosphoribosyl-anthranilate isomerase, and indoleglycerol-phosphate synthetase (181, 260) (Fig. 11). trp-1 codes for the beta subunit of the aggregate (546); it specifies phosphoribosyl-anthranilate isomerase, indoleglycerol-phosphate synthetase, and collaboratively the glutamine amino transferase activity of anthranilate synthetase (29, 181, 502). Strains carrying different alleles differ in lacking one or more of the three activities, e.g., trp-1 (allele 15) lacks all three activities; trp-1 (20) lacks only phosphoribosyl- anthranilate isomerase, trp-1C (1) lacks only anthranilate synthetase, trp-1 (25) lacks both phosphoribosyl-anthranilate isomerase and indoleglycerol-phosphate synthetase, etc. (259). (To avoid confusion, note that in reference 259 and related papers, the same "allele number" may be used for a trp-2 mutation, a trp-1 mutation [non-anthranilate-utilizing], and a trp-1C mutation [anthranilate utilizing]; mutations of the last class are listed by FGSC as trp-1 with the allele number prefixed by C.) Strains carrying different alleles differ in their ability to form aggregates (181, 259). Association between trp-1 and trp-2 products is essential for glutamine-dependent anthranilate synthetase activity but not the other two activities (181). The trp-1 gene has been cloned (545, 925), sequenced (925), and reintroduced into Neurospora by transformation (925). It is only partially expressed in E. coli. Fine-structure maps (10, 259). Complementation maps (10, 163). Reviewed as example of gene fusion (218). Nonsense allele used to demonstrate restoration of normal enzyme aggregate by supersuppressors (183). Alleles that accumulate anthranilate are scorable by blue fluorescence under long-wave UV after 2 to 5 days of growth on minimal medium plus indole (10 µg /ml), 34°C (814, 816). Aging cultures may produce brown pigment; blue fluorescence disappears as pigment forms.

trp-2: tryptophan-2
VIR. Right of del (0 to 13%). Left of un-23 (5 to 27%), T(OY320), and ws-1 (38%) (818, 822, 1019, PB).

Uses kynurenine, anthranilic acid, indole, or tryptophan (96). Kynurenine is utilized by conversion to anthranilate (447). Inferred to be the structural gene for the alpha subunit of the anthranilate synthetase complex (546). The gene product catalyzes anthranilate synthesis with ammonia but not with glutamine as the amino donor (29). Specifies anthranitate synthetase (glutamine linked) in collaboration with trp-1 in trifunctional trp-1+-trp-2+ enzyme aggregate (181, 259) (Fig. 11); see trp-1. Nonsense allele used to isolate supersuppressors (954) and to study enzyme complex restored by supersuppressors (183).

trp-3: tryptophan-3
IIR. Right of fl (2 to 6%). Left of rip-1 (9%) and un-5 (10%) (816, PB). (1166). Uses tryptophan (685); strains carrying some alleles also use indole (4). Structural gene for tryptophan synthetase (1167), called tryptophan desmolase in early literature. Tryptophan synthetase catalyzes three reactions: indoleglycerol-phosphate -> tryptophan, indole tryptophan, and indoleglycerol-phosphate <-> indole (Fig. 11). In Neurospora, all three reactions are catalyzed by a single protein, which is specified by a single gene (645, 1167). Mutants lack indoleglycerol-phosphate -> tryptophan activity but differ with respect to the other activities; e.g., strains carrying trp-3 allele (td141 are blocked in indoleglycerol-phosphate utilization but can use indole; trp-3 (td100) can synthesize indole but not convert it to tryptophan; trp-3 (td140) lacks all three activities. (See references 582 and 1049 for citations and characteristics of other mutants.) Used extensively for studies of gene structure in relation to enzymatic activity (257, 582 and references therein, 1167). The active enzyme is a homooligomer (645) thought to have two domains (644 and references therein). Biochemical studies of complementation between alleles: in vivo (582, 583) and in vitro (1048 and references therein). Complementation maps (4, 5, 9 and references therein, 582). Fine-structure maps (5, 540, 582, 1049). Reviewed as example of gene fusion (218). trp-3 mutant C83 provided the first proved example in Neurospora of gene-controlled loss of enzyme activity (685); trp-3 mutant S1952 provided the first example of allele-specific suppression restoring functional wild-type-like enzyme (1166). Allele td140 is supersuppressible (954, 955). Certain classes of trp-3 mutants are osmotic remediable (583). Called td and tryp-3.

trp-4: tryptophan-4
IVR. Between his-5 (3 to 7%) and leu-2 (1 to 2%) (633, 991). (47).

Uses tryptophan or indole (750). Deficient in anthranilate phosphoribosyl transferase (1126) (Fig. 11). Scorable by blue fluorescence (anthranilate) in medium under long-wave UV after 2 to 5 days of growth on minimal medium plus indole (10 µg /ml), 34°C. Initial stocks of the first trp-4 mutant were inhibited by suboptimal concentrations of tryptophan (750), but derivatives have been obtained that are free of this problem (909).

trp-5: tryptophan-5
VR. Right of pab-1 and int (4%). Left of met-3 (4%) (6, PB). (14). Uses anthranilate, indole, or tryptophan (14). Tryptophanyl-tRNA synthetase activity is < 5% that of the wild type (742). Anthranilate synthetase and tryptophan synthetase derepressed (742). Not temperature sensitive.

try, tryp: tryptophan
Changed to trp.

ts: tan spore
VR. Linked to inl (4%) (734).

Ascospores slow to mature, remaining light brown when wild-type ascospores have blackened. Expressed autonomously, allowing visual scoring in heterozygous asci. Only a small minority of ts ascospores, that have darkened with age, are capable of germination. Photograph of asci (734). Used to study multiple (737) and selective (314) fertilization, preferential segregation (735), and factors affecting crossing-over frequency (586, 736).

tu: tuft
IIR. Between pe (8%) and fl (19%) (613).

Conidia mostly in clusters at top of slant (613). (Stock lost.)

ty: tyrosinase
This symbol is used for regulatory genes ty-1, ty-2, ty-3, and ty-4. Strains carrying these genes are prototrophic, growing on unsupplemented minimal medium. The structural gene is symbolized T.

ty-1: tyrosinase-1
IIIR. Linked to tyr-1 (0 to 6%) and dow (21%) (1115, PB).

Tyrosinase repressed. Recessive (475, 477). Uninducible by protein synthesis inhibitors in the sexual phase but inducible in vegetative culture (472, 477). Prototrophic. Velvet-like vegetative morphology. Female infertile (no or few perithecia) but fertile as male. Infertility is recessive in heterokaryons (475). Low ascospore viability (459). Scored by color reaction with DL-3,4-dihydroxyphenylalanine as the substrate (475, 477) or by morphology and female sterility.

ty-2: tyrosinase-2
IR. Right of al-2 (459).

Tyrosinase repressed. Recessive (475, 477). Uninducible by protein synthesis inhibitors, e.g., cycloheximide, in the sexual phase, but inducible in vegetative culture (472, 477). Short aerial hyphae (459), although described earlier as morphologically normal (475). Female infertile but fertile as the male. Infertility is recessive in heterokaryons (475). Prototrophic. Score by color reaction with DL-3,4-dihydroxyphenylalanine as the substrate (475, 477) or by morphology or female sterility.

ty-3: tyrosinase-3
IIIR. Near the centromere; left of ad-4 (W.L. Chan, Ph.D. thesis, University of Malaya, Kuala Lumpur, 1977, cited in reference 460). Not allelic with T or ff-3 (193; N.H. Horowitz and H. Macleod, cited in reference 332).

Tyrosinase repressed. Uninducible by protein synthesis inhibitors, e.g., cycloheximide, in vegetative culture (322, 460; N.H. Horowitz and H. Macleod, cited in reference 332). Originally reported to be female sterile and morphologically abnormal; subsequently, these properties were shown due to a second, nonallelic mutation, ff-3. The ty-3 single mutant is female fertile and morphologically normal (193). Score by color reaction with DL-DOPA as the substrate (475, 477). The original strain containing both ty-3 and ff-3 is called T22; it also contained ty-4, q.v.

ty-4: tyrosinase-4
Unmapped.

Tyrosinase repressed. Uninducible by total starvation in sodium phosphate buffer, but can be induced by cycloheximide. Found in strain T22, which also contains ty-3 and ff-3 (460; W.L. Chan, Ph.D. thesis, University of Malaya, Kuala Lumpur, 1977, cited in reference 460); also present in some Emerson wild types (460).

tyr-1: tyrosine-1
IIIR. Right of vel (3 to 5%) and phe-2 (2 to 4%). Left of un-17 (4%) (316, 816, PB; R.L. Metzenberg, personal communication). (47).

Requires tyrosine (1055). Lacks prephenate dehydrogenase activity (40, 316) (Fig. 11). Shows phenotypic adaptation after a lag, attaining the wild-type growth rate on minimal medium. Adaptation is not carried through conidia (1055). Allele UT145 formerly called tyr-3 (316).

tyr-2: tyrosine-2
IR. Between the T(4540) breakpoints; hence, between nic-2 and thi-1 (10%). Probably left of cr-1 (2%) (812, PB).

Requires tyrosine (812). Decreased prephenate dehydrogenase activity (316); pe-like morphology. Female sterile. tyr- ascospores not fully pigmented. Growth is suboptimal even on fully supplemented medium. Scoring by growth on slants is treacherous; adapts to growth on minimal medium after several days. Can be scored by darkening of tyrosine-supplemented minimal medium.

tyr-3: tyrosine-3
See tyr-1.

tyr-s
See tys.

tys: tyrosine sensitive
I. Right of mating type (6%) (PB) (1156).

Growth inhibited 80% by 0.07 MM L-tyrosine. Growth of tys strains on minimal medium is also inhibited by glycyl-leucyl-tyrosine and by various tyrosine analogs. Uptake of L-p-[14C]tyrosine is increased slightly, but this is not proposed as the cause of the inhibition. Primary defect unknown. (1156). Used to obtain the oligopeptide transport mutant glt, which is resistant to glycyl-leucyl-tyrosine but not to tyrosine (1155). Called tyr-s (1155, 1156).

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