Yolk polypeptide processing in the fat body of Sarcophaga bullata

✍ Scribed by Johan Cardoen; Roger Huybrechts; Arnold De Loof

• Publisher: John Wiley and Sons
• Year: 1986
• Tongue: English
• Weight: 610 KB
• Volume: 3
• Category: Article
• ISSN: 0739-4462
• DOI: 10.1002/arch.940030710

✦ Synopsis

In Sarcophaga bullata there are at least three genes coding for t h e major yolk polypeptides. By means of t h e reticulocyte cell-free translation system in combination with dog pancreatic microsomal membranes, it was demonstrated that minor processing of the peptides occurs in Sarcophaga. Prior to secretion, only t h e cleavage of t h e signal peptide is observed.

In vitro translation experiments also revealed that Sarcophaga males require only 20-hydroxyecdysone and not juvenile hormone for the induction of t h e yolk polypeptide transcription. Following a single injection of 20hydroxyecdysone in males, in vivo pulse labeling experiments showed that translation of t h e yolk polypeptides continues for n o longer than 24-36 h; only a continuous stimulation by 20-hydroxyecdysone results in prolonged synthesis of t h e yolk polypeptides.