K. Miura et al., CLONING OF MESSENGER-RNA SEQUENCES FOR 2 ANTIBACTERIAL PEPTIDES IN A HEMIPTERAN INSECT, RIPTORTUS-CLAVATUS, Zoological science, 13(1), 1996, pp. 111-117
Escherichia coil injection rapidly induced bactericidal activity in th
e hemolymph of a hemipteran insect, Riptortus clavatus. This activity
reached its maximum at 9 hr after injection and thereafter declined sl
owly. Two types of cDNA clones involved in this response were isolated
by differential screening. The predominant type encoded for an open r
eading frame of 678 amino acids, which consisted of fourteen tandem re
peats. Each repeat was rich in charged residues and had a proline-rich
region which had striking sequence similarities to proline-rich antib
acterial peptides from other insect species, indicating these clones e
ncode a multipeptide precursor of antibacterial peptides. The other ty
pe encoded for a glycine-rich peptide similar to a known antibacterial
peptide as well. Northern blot analyses revealed rapid induction of m
RNAs corresponding to these clones after the injection. To our knowled
ge, this is the first report on the mRNA sequences of antibacterial pe
ptides of hemimetabolous insects, and the second report on the occurre
nce of multipeptide precursor structure in insect antibacterial peptid
es.