Major role in the synthesis of nucleoside triphosphates other than ATP. The ATP gamma phosphate is transferred to the NDP beta phosphate via a ping-pong mechanism, using a phosphorylated active-site intermediate.

(UniProt, P08879)

Homozygotes die in late third larval instar; wing discs variably hypoplastic; other discs appear grossly normal. Trypan blue staining reveals cell death in wing disc, either in area of presumptive wing blade, or scattered throughout disc; other discs reveal lesser amounts of cell death later in development than in wing discs. Extensive lipid vacuolization in larval ventral ganglion, brain lobes, and proventriculus. Mutant discs exhibit slow growth when transplanted into wildtype hosts; normal discs in mutant hosts grow normally. Metamorphosis of eye-antennal, wing, and leg discs when transplanted into normal larvae severely restricted; few or no adult structures develop; mutant ovaries do not survive transplantation to wild-type hosts; however, transplanted awd pole cells capable of producing both awd/+ and awd/awd progeny. Epidermal clones nearly lethal and with thin, short, bent bristles and hairs when induced early; survive in reduced numbers and size when induced late.

An antimorphic allele; no phenotypic effects, either when homozygous or heterozygous; however, it is a dominant conditional lethal, which is lethal in combination with pn, i.e., pn/Y; awdK/+ males or pn/pn; awdK/+ females. awdK does not interact with any other eye-color mutant. Interacts lethally with all standard alleles of pn tested; however, pnts-ek insensitive to awdK at permissive temperatures, whereas nine other temperature-sensitive alleles of pn are insensitive under all conditions. Lethal phase of pn;awdK genotypes begins in early second larval instar and lasts until after the time that normal larvae pupate. Using pnts-ek, the temperature-sensitive period of the pn component of the lethal interaction determined to begin in second instar and last until eclosion. pn;awdK sons of pn mothers appear to die earlier than those of pn/+ mothers, suggesting a maternal effect of pn+, which is revealed in the presence of awdK (Hackstein, 1971, Mol. Gen. Genet. 111: 371-76). Fate mapping in pn//pn/+;awdK/+ gynandromorphs places the focus of the lethal interaction in the midventral part of the blastoderm, not a focus of pteridine biosynthesis. awdK eye disks transplanted into pn hosts develop autonomously as do the reciprocal transplants (Grell, 1958, DIS 32: 123-24). The levels of awd transcript are normal in (1) pn, (2) awdK/+, and (3) pn;awdK/+ flies; however, only the first two genotypes accumulate normal levels of the AWD polypeptide, the last having little or none, despite the presence of one copy of awd+. pn;awdK/+ larvae die in early third instar, whereas those that are pn;awdK/+/+ die at the end of L3.