Gene: tryptophan-1 IIIR
tryptophan-1
locus: trp-1
locus_name: tryptophan-1
organism_type: B
chromosome_number: III
chromosome_side: R
link_group: IIIR
cultural_requirements: 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-1Cmutation [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-2products 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.
enzyme_id: 65
Enzyme: anthranilate synthetase
anid_name: trpC
near_l: ad-2 (1 to 7%)
near_r: ro-2 (2 to 12%); Linked to fpr-3 (< 1%)
neu_name:
supplement: tryptophan or indole
image_url:
Strains
References
