Molecular characterization of a cDNA from Pseudaletia unipuncta encoding the Manduca sexta allatostatin peptide (Mas-AST).
A 15-residue neuropeptide, Manduca sexta allatostatin (Mas-AST), strongly inhibits juvenile hormone (JH) biosynthesis in vitro by corpora allata (CA) from Manduca fifth-stadium larvae and adult females as well as Helicoverpa zea adult females (Kramer et al., 1991 Proc. Natl. Acad. Sci (USA) 88, 9458-9462). In contrast, this study found that 1.0 microM Mas-AST has no JH biosynthesis inhibitory activity in Pseudaletia unipuncta sixth instar larvae or newly-emerged (day 0) adults but inhibited CA of 5-day-old adult females by 60%. From a P. unipuncta brain cDNA library, was isolated a cDNA that encodes a 125 amino acid polypeptide containing the Mas-AST sequence. Within the precursor, Mas-AST is situated at the carboxy terminus and is flanked by different dibasic proteolytic cleavage signals. The Pseudaletia gene specifying the Mas-AST peptide is present as a single copy per haploid genome. Expression of this gene was low in Pseudaletia sixth instar larvae, prepupae and early pupae but was relatively high in late pupae, and day 1 and 3 adults of both sexes. In day 5 adults, the relative transcript level appears to be maintained in females but declines in males. This pattern of Mas-AST expression does not correlate well with the profile of JH biosynthesis in Pseudaletia, which increases during the first 5 days of adult life, suggesting additional or alternative functions for this peptide.
Jansons
I S
IS
Department of Biology, Queen's University, Kingston, ON, Canada.
Cusson
M
M
McNeil
J N
JN
Tobe
S S
SS
Bendena
W G
WG
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D018076:DNA, Complementary; D005260:Female; D015870:Gene Expression; D019476:Insect Proteins; D007605:Juvenile Hormones / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D008297:Male; D018402:Manduca / Q000378:metabolism; D008969:Molecular Sequence Data; D009036:Moths / Q000235:genetics*; D009479:Neuropeptides / Q000235:genetics; D010455:Peptides / Q000235:genetics*; D011498:Protein Precursors / Q000235:genetics; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives; D012333:RNA, Messenger
D018076:DNA, Complementary; D019476:Insect Proteins; D007605:Juvenile Hormones; D009479:Neuropeptides; D010455:Peptides; D011498:Protein Precursors; D012333:RNA, Messenger; C071432:allatostatin protein, Manduca sexta; D011761:Pyrrolidonecarboxylic Acid