FGSC #1571

Mutant Type

Genus: N

reporting_genes: rec-1+;rec-3;cot-1;am

species: Neurospora crassa

allele: no#;no#;C102(t);47305

stock: 3675

glasgow:

mutagen:

Depositor: DGC

Link Group: VR;IL;IVR;VR

MT: A

Species No: 10

gene_back:

oppmt: 0

trans:

ref1: See references in letter of 6/18/68

ref2: https://www.publish.csiro.au/BI/pdf/BI9661039

site:

country:

ksudc_link: https://digital.lib.k-state.edu/item/neurospora-crassa/fgsc-1571

ksudc_link_html: https://digital.lib.k-state.edu/item/neurospora-crassa/fgsc-1571 ↗

Genes

Locus	Cultural Requirements	Link Group	Type
rec-1	VR. Between ro-4 (7%) and asn (5%) (159). (165) Presence of allele rec-1+ reduces recombination within the loci his-1 (VR) (520, 1070) and nit-2 (IL) (155, 157) (Fig. 22). A recessive allele from another lineage was called rec-z until probable identity with rec-1 was established (157). rec-1+ does not affect recombination within any other hislocus tested (172).	VR	B
rec-3	IL. Between acr-3 (1 to 2%) and arg-3 (2 to 6%) (168, 173). (166) Presence of allele rec-3+ reduces recombination within the loci his-2 (IR) and am (VR) but not in adjoining regions or within gul-1, which is less than 0.3% from am (173, 997, 998). Crossing over is also reduced in the interval between sn and his-2 (174) (Fig. 22). Three alleles known: rec-3, rec-3L, and rec-3+ (168). A recessive allele from another lineage was earlier called rec-x(see reference 167).	IL	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
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