Bc. Donly et al., CHARACTERIZATION OF THE GENE FOR LEUCOMYOSUPPRESSIN AND ITS EXPRESSION IN THE BRAIN OF THE COCKROACH DIPLOPTERA-PUNCTATA, Insect biochemistry and molecular biology, 26(6), 1996, pp. 627-637
Using HPLC separation, radioimmunoassay, and subsequent bioassay, we h
ave detected the presence of an active peptide, which co-elutes with t
he insect myoinhibitory peptide leucomyosuppressin, in the brain of th
e cockroach Diploptera punctata, We have isolated a cDNA encoding the
precursor for this peptide from cDNA libraries representing D. punctat
a brain RNA, The cDNA sequence contains an open reading frame that upo
n translation would result in a prepropolypeptide of 96 amino acids. P
roteolytic cleavage of the predicted precursor could result in several
peptides, including a 10 amino acid C-terminal peptide that would, up
on modification of the NH2 and COOH-terminal amino acids, be identical
to the insect FLRFamide, leucomyosuppressin, No other RFamide product
s are predicted to be processed from the precursor, Southern blot anal
ysis indicates that the gene is present in the D. punctata genome in a
single copy, Northern blot analysis shows that the gene is predominan
tly expressed as a 3.8 kb mRNA in cockroach brain. Study of the expres
sion of the leucomyosuppressin gene in D. punctata brain, using in sit
u hybridization, indicates that expression occurs primarily in the par
s intercerebralis of the protocerebrum, a region showing abundant FMRF
amide-like immunoreactive neurosecretory cells, Immunohistochemistry a
nd HPLC coupled to radioimmunoassay indicates that leucomyosuppressin
represents a significant proportion of FMRFamide-related peptide produ
ction in the brain, However, HPLC analysis also indicates the presence
of significant levels of other related peptides, demonstrating the pr
esence of more than one FMRFamide-related gene in this insect. Crown c
opyright (C) 1996 Published by Elsevier Science Ltd.