Molecular cloning of the precursor cDNA for schistostatins, locust allatostatin-like peptides with myoinhibiting properties.
The cDNA encoding the precursor polypeptide for schistostatins, allatostatin-like peptides which have been shown to inhibit peristaltic movements of the lateral oviducts of Schistocerca gregaria, has been cloned and sequenced. Translation of this sequence reveals the presence of a pre-proschistostatin consisting of 283 amino acids. It contains ten different peptide sequences which are flanked by dibasic cleavage sites and C-terminal amidation signals. Eight of these peptides were identical to the schistostatins (or Scg-ASTs) that were previously purified from Schistocerca gregaria brain extracts. Two novel peptide sequences were discovered. One of these is the first AST-like peptide which has a C-terminal valine residue. Two peptides contain within their sequence an internal dibasic site which suggests a possible role for alternative processing and/or degradation. The schistostatin precursor differs from cockroach pre-proallatostatins in size, in sequence and in organization. It contains a lower number of peptides (10 versus 13 or 14) which are interrupted only once by an acidic spacer region (versus four in Diploptera punctata and Periplaneta americana). Northern analysis showed the presence of a 2.4 kb mRNA band in the locust central nervous system and midgut. This indicates that schistostatins, like other ASTs, are a good example of insect brain/gut peptides.
Laboratory for Developmental Physiology and Molecular Biology, K.U. Leuven, Belgium.
J
J
Vanden Broeck
D
D
Veelaert
W G
WG
Bendena
S S
SS
Tobe
A
A
De Loof
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D003001:Cloning, Molecular; D018076:DNA, Complementary; D006110:Grasshoppers; D008969:Molecular Sequence Data; D009119:Muscle Contraction / Q000187:drug effects*; D009479:Neuropeptides / Q000737:chemistry / Q000235:genetics* / Q000494:pharmacology; D010057:Oviducts / Q000187:drug effects / Q000502:physiology; D016133:Polymerase Chain Reaction; D011498:Protein Precursors / Q000737:chemistry / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism; D017385:Sequence Homology
D018076:DNA, Complementary; D009479:Neuropeptides; D011498:Protein Precursors; D012333:RNA, Messenger; C103956:schistostatin; C076523:allatostatin