FGSC #2572

Mutant Type

Genus: N

reporting_genes: rec-2;cog+;cot-1;his-3;am

species: Neurospora crassa

allele: no#;Y8743cg;C102(t);K874;K314

stock: 13046

glasgow:

mutagen:

Depositor: DGC

Link Group: VR;IR;IVR;IR;VR

MT: a

Species No: 10

gene_back:

oppmt: 0

trans:

ref1: https://doi.org/10.1071/bi9740561

ref2: Catcheside 1960 Proc Roy Soc London 153:179-194, https://doi.org/10.1098/rspb.1960.0095

site:

country:

ksudc_link: https://digital.lib.k-state.edu/item/neurospora-crassa/fgsc-2572

ksudc_link_html: https://digital.lib.k-state.edu/item/neurospora-crassa/fgsc-2572 ↗

Genes

Locus	Cultural Requirements	Link Group	Type
cog	IR. Between his-3 (1 to 3%) and ad-3A (2 to 7%) (27, 171). The postulated site for initiating local recombination in meiosis. Affects recombination in adjoining regions, in the absence of rec-2+. Presence of cog+ then increases recombination within his-3 (27) and crossing over between his-3 and ad-3 (171). The allele for high recombination is completely dominant, and its effect is specifically on the his-3 alleles in chromatids that contain cog+, as evidenced by crosses heterozygous for reciprocal translocation TM429, which has a breakpoint between sites within the his-3 locus (171). See rec and rec-2; see Fig. 22.	IR	B
cot-1	IVR. Between pan-1 (2%) and his-4 (1 to 6%) (692, 812, 816). Extremely colonial at 34°C, but completely normal growth, morphology, and fertility at 25°C and below. Linear growth is maximum at 24°C (374). Becomes colonial at 32°C; colonies from ascospores or conidia are viable and continue to grow slowly with dense branching, but do not conidiate. They quickly resume normal growth when shifted to a permissive temperature (692, 1068). Recessive in duplications (808); apparent dominance in heterokaryons (374) may have resulted from a shift in nuclear ratios. Used in studies of septation and branching (202), growth-inhibiting mucopolysaccharide (878, 879), and sulfate transport (641). Cell wall analysis (374). Growth is stimulated by lysine or arginine (0.1 mM) on glucose media at high temperatures (615). Because of high viability and tightly restricted growth at restrictive temperatures and normality at 25°C, cot-1 mutants have valuable technical applications. For example, crosses homozygous for cot-1 have been used in combination with sorbose for experiments with rec genes, where high-density ascospore platings are required for precise quantitative analysis of intralocus recombination (e.g., references 165, 997, and 1070). In another application, when shifted up after initial growth at the permissive low temperature, cot-1hyphae assume a "bottle brush" appearance with small side branches (692). This has been used to select uvs mutants by subsurface survival on UV-irradiated plates containing p-aminobenzoic acid (938; D.E.A. Catcheside, personal communication). cot-1 conidia or ascospores from cot-1 x cot-1crosses are used for replication in a protocol involving transfer by filter paper (615). For suppressors of cot-1, see gul.	IVR	B
his-3	IR. Right of met-10 (R.L. Metzenberg, personal communication). Left of cog (1 to 3%) (172,174), ure-4 (1%) (78), and ad-3A (1%) (271). (434)Requires histidine (434). Complex gene coding for histidinol dehydrogenase, phosphoribosyladenosine 5'-triphosphate-pyrophosphohydrolase, and phosphoribosyl-adenosine 5'-monophosphate-cyclohydrolase (16, 673) (Fig. 14). All three activities appear to be catalyzed by a single protein (673). Strains carrying different individual alleles may lack only the early reaction(s) or only histidinol dehydrogenase, or both. Those that lack only histidinol dehydrogenase accumulate histidinol (16, 162, 1123). Mutants produce cross-reacting material (220). Used to study intralocus complementation and recombination (15, 16, 27, 162, 164, 171, 172, 1121, 1122, 1124). Intralocus recombination is regulated by cog and by rec-2 (27, 171); it is not affected by rec-1 (172). Translocation T(IR;VII)TM429, with one breakpoint in his-3, has been used to show that cog is cis-acting (171). Initial alleles: C140 and T1710 (= C1710).	IR	B
rec-2	VR. Between sp and am (174). (993) Presence of dominant allele rec-2+ reduces recombination within the his-3locus (IR); also reduces crossing over in the intervals pyr-3-his-5(IVR), his-3-ad-3 (IR), and arg-3-sn (IL) (171, 74, 992) (Fig. 22). Interacts with cog in affecting recombination in his-3 and crossing over between his-3and ad-3 (27, 171). Used in conjunction with translocation TM429to demonstrate the cis action of cog+ on recombination between sites in his-3(171). (See cog.) Recessive rec-3 alleles from other lineages were called rec-4, rec-5, or rec-w until identity was demonstrated (see reference 167). Map locations of the rec genes. Arrows show the sites where they are known to affect meiotic intra- or interlocus recombination frequencies, and the magnitude of the effect (170 and references therein; D.E.A. Catcheside, personal communication).	VR	B
am	VR. Right of ure-2 (2%) and sp (4 to 8%). Left of gul-1(<<1%) and ace-5(<1%) (122, 570, 579, 998). (R.W. Barratt, (cited in reference 1036) Structural gene for nicotinamide adenine dinucleotide phosphate (NADP)-glutamate dehydrogenase (336) (see Fig. 19), for which a complete 452-residue amino acid sequence has been obtained (465). Requires a source of alpha-amino nitrogen for growth, alanine being a good supplement (e.g., reference 997). Readily scorable at 25 C; leaky at 34°C (42). Leaky growth and adaptation on minimal medium are prevented by 0.02 M glycine (782, 783) or by en(am)-1, en(am)-2, or nit-2, q.v. The ammutants show abnormal regulation of reduced nicotinamide adenine dinucleotide (NADH)-glutamate dehydrogenase and are synergistic with nit-2 in this effect (226). Some am alleles (e.g., RU1) suppress the pyrimidine requirement caused by pyr-3 (CPS- ACT+) mutations (1137). Used for the first demonstration of complementation between alleles in vivo (344) (simultaneous with independent demonstration with ad-4). In vitro complementation (342). Used for studies of complementation mechanism (199, 200, 1120). Used for fine-structure mapping (337, 338). Control of intralocus recombination by rec-3(996-998). Used to study colinearity of the gene and gene product, internal suppressors (105, 340, 465), and the action of supersuppressors (954, 955). The functional defects in several mutant enzymes with single amino acid replacements have been defined: am1 mutant enzymes fail to bind NADPH (1120); am2, am3, am19, am130, and am131 enzymes are stabilized in the inactive conformational form (30, 200, 336, 556, 1044), and all are complementable by am1; am14 is osmotically reparable and is thought to have unstable quaternary structure (340). Used in a study showing glutamine to have a role as corepressor of uricase synthesis (1118). Used to study nitrogen assimilation and metabolism (503) and nitrogen metabolite repression (186, 291). Efficient procedure for selecting new am mutants (551). Spectrum of ultraviolet irradiation (UV)- and nitrous acid-induced mutants (554). Allele am17 has a chain-terminating codon of either the amber or ochre type at residue 313 of glutamate dehydrogenase, based on amino acid replacements in revertants and by ssu-1 (956). Allele 6 is a frameshift mutation with an insertion in the Ser5 codon (985). Allele 126 is highly unstable (553). Allele 132 is a deletion (1162). The am+ gene has been cloned in Escherichia coli(J.R.S. Fincham, personal communication) and transformed back into Neurospora (J.A. Kinsey, personal communication).	VR	B