FGSC #228

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Reporting Genes: nit-1 al-1 nic-1 os-1

Species: crassa

Allele: 34547 34508 3416 B135

Alternate Strain Number: 1128

Depositor: DDP

Linkage Group: IR IR IR IR

Mating Type: A

Species Number: 10

Deposit Sheet ↗

Genes

Locus	Cultural Requirements	Link Group	Type
nit-1	IR. Right of Tp(T54M94) and ad-9 (3 to 15%). Left of cyh-1(6%) (466, 496, 816). (482)Cannot use nitrate or hypoxanthine as a nitrogen source, but uses nitrite, ammonia, or amino acids (1000). Does not prevent formation or nitrate reductase apoprotein (999), but lacks the molybdenum-containing cofactor common to nitrate reductase and xanthine dehydrogenase (591, 741) (Fig. 19 and 24). The nitrate reductase in nit-1 extracts does not catalyze the complete electron transport sequence from NADPH to N03 but does catalyze the initial part of this sequence if a suitable electron acceptor (e.g., cytochrome c) is provided (999). See reference 198 for a model of interaction of nit-1 and nit-3 gene products. See references 226, 999, and 1000 for regulation.	IR	B
os-1	IR. Between nic-1 (10 to 29%) and arg-13 (1%) (789, 812, 816). (M.R. Emerson, cited in reference 789) Sensitive to high osmotic pressure. Readily scored by morphology on nonmoist slants or by failure to grow on media with 4% NaCl. Most os-1 alleles result in cultures that form no or few conidia on agar slants. Alleles NM233t and NM204t are heat sensitive (25°C versus 34°C). In media of high osmolarity, os-1 strains form protoplasts (323, 438). os-1 (Bl35) is an essential genotypic component of the wall-less strain slime (321). Protoplasts of strains carrying heatsensitive allele NM233t are stable at 37 C, with a 7.5-h redoubling time, and show good regeneration. The biochemical defect differs from that affected by either polyoxin or sorbose (chitin or glucan syntheses) (970, 971). Cell wall pores are four times larger in an os-1 mutant than in the wild type; os-1 also has a higher exclusion threshold and a 30-fold-higher galactosamine/ glucosamine ratio (1083, 1084). Intralocus complementation (676). Allele Y256M209 called flm-1.	IR	B
nic-1	IR. Right of ace-3 (<1%), lys-1 (1%), and In(OY323). Left of os-1(10 to 29%) (2, 57, 131, 578, 789, 816, 907). (482) Uses nicotinic acid or nicotinamide, but not precursors (97, 100) (Fig. 18). Accumulates quinolinic acid (100). Used to study intralocus recombination (907). Called the q locus.	IR	B
al-1	IR. Right of hom (<1%), arg-6 (<1 to 4%), T(T54M94), and al-2. Left of lys-3 (9%). (797, 808; D.D. Perkins, unpublished data). (482) Carotenoids abnormal. Strains carrying the various alleles differ widely in phenotype, ranging from white (e.g., 4637) and "aurescent" (pigment in peripheral conidia and conidiophores, 34508) to yellow mycelia and conidia (e.g., ALS4 and RES-25). See, for example, reference 1042. Strains carrying alleles ALS-14, RES-6, 34508, and RES-25 contain large amounts of phytoene (99 to 100% of the total neutral carotenoids), suggesting a lesion that affects phytoene dehydrogenase (398, 1039) (see Fig. 9). Strains carrying allele RWT-ylo accumulate zeta carotene and smaller amounts of neurosporene, suggesting a leaky block of the step between these intermediates (1071). It is not known whether phytoene dehydrogenase catalyzes the whole series of dehydrogenations or whether leakiness of this enzyme accounts for the different mutant phenotypes. For complementation tests, see references 500, 1039, and 1041. Fine-structure mapping (500, 1042). Translocation T(4637), inseparable from al-1, was the first albino mutation and one of the first chromosome rearrangements in Neurospora to be identified and studied (656). Allele 34508 called aur: aurescent.	IR	B