FGSC #8596

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Reporting Genes: eas trp-3

Species: crassa

Allele: JD105, td24

Alternate Strain Number: 4856-1

Depositor: DDP

Linkage Group: IIR,R

Mating Type: A

Species Number: 10

Deposit Sheet ↗

Genes

Locus	Cultural Requirements	Link Group	Type
eas	IIR. Linked to rip-1 (1/151), trp-3 (0/71), and fl (1/52) (PB). (967)Conidia and aerial hyphae are readily wetted by water; in contrast, those of wild type are hydrophobic. Resembles csp mutants in that conidia do not readily become airborne, but differs from csp mutants in that conidia do not remain joined in the proconidial chains (967). Rodlets are lacking from the surface of conidia (75). Conidiating cultures can be scored by adding a drop of water to the culture, by tapping an inverted slant (967), or by transferring conidia to liquid (PB). Not scorable in combination with fl. Somewhat sensitive to high osmotic pressure (PB). A class of slow-growing progeny is produced from crosses heterozygous or homozygous for eas(811).	IIR	B
trp-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-3mutants are osmotic remediable (583). Called td and tryp-3.	IIR	B