Developmentally regulated alternate modes of expression of the Gpdh locus of Drosophila.

Abstract

Immunoblot analyses have been performed on extracts prepared from Drosophila melanogaster. Those analyses have revealed two subunit forms of enzyme glycerol 3‐phosphate dehydrogenase (GPDH) in larval tissues and in adult abdominal tissues. Thoracic tissue, which accounts for the bulk of the adult GPDH, has only one subunit form, the smaller. The two subunit forms differ by approximately 2400 daltons. In agreement with previous genetic and biochemical data indicating that this enzyme is encoded by a single structural gene, analyses of extracts prepared from a strain carrying a GPDH null mutation detect no GPDH polypeptides in larvae or adults. Similarly, analyses of extracts prepared from a strain carrying a mutation which produces a GPDH polypeptide that differs in size from wild‐type reveal a change in the adult thoracic GPDH polypeptide as well as a change in both GPDH polypeptides found in larvae. Total Drosophila RNA prepared from larvae or newly eclosed adults has been translated in a mRNA‐dependent cell‐free system. GDPH was immunoprecipitated from the translation products and analyzed. Two subunit forms of GPDH were immunoprecipitated from translation products whose synthesis was directed by larval RNA and only one was detected in the polypeptides synthesized from adult RNA. The GPDH polypeptides synthesized in vitro are approximately the same size as the corresponding polypeptides found in vivo. The relative proportion of total GPDH represented by each subunit form synthesized in vitro is similar to those found in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)

Flight muscle function in Drosophila requires colocalization of glycolytic enzymes.

“…Probes for the transcript of the ribosomal protein rp49 were used as a control. (B) Developmental Westem blot; Extracts were prepared from flies at the indicated number of days after emergence, electrophoresed on 12.5% SDS-polyacrylamide gels, electroblotted, and reacted with anti-GPDH serum as described previously (Skuse and Sullivan, 1985). were stained for GPDH, and we observed that the great majority, if not all, of GPDH-1 in flight muscles is found localized along the sarcomere of the myofibrils in an ordered pattern of alternating strongly fluorescent and somewhat more weakly fluorescent zones ( Figure 2A).…”

“…GPDH-3 is normally found in nonmuscle cells, but its localization in nonmuscle cells has not yet been characterized. However, because GPDH-3 is known to participate with glycerol-3-phosphate oxidase, a known mitochondrial enzyme, in accomplishing the glycerolphosphate shuttle (MacIntyre and Davis, 1987) (Skuse and Sullivan, 1985). though variable, is within the range that might be expected for a set of lines carrying independent transposons.…”

“…P-element transformation was conducted using a standard protocol (Rubin and Spradling 1982) and the vector pw8 (Klemenz, et al, 1987). Transformants, w+ flies, were characterized for GPDH content using Western blots and histochemical staining of dissected tissues (Skuse and Sullivan, 1985;von Kalm et al, 1989). The levels GPDH and pattern of GPDH expression in each of these are comparable with wild-type.…”

“…Antibodies against GPDH and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) have been characterized previously, and their specificities have been demonstrated (Skuse and Sullivan, 1985;Sullivan et al, 1985). They both are polyclonal antibodies, raised in rabbits, using enzymes purified by standard biochemical procedures as antigens.…”

“…They both are polyclonal antibodies, raised in rabbits, using enzymes purified by standard biochemical procedures as antigens. Westem blots using each antibody have been described previously (Skuse and Sullivan, 1985;Sullivan et al, 1985).…”