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Biochemical characterization, developmental expression, and induction of the immune protein scolexin from Manduca sexta
Author(s) -
Kyriakides T. R.,
McKillip J. L.,
Spence K. D.
Publication year - 1995
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/arch.940290305
Subject(s) - manduca sexta , biology , hemolymph , biochemistry , manduca , sialic acid , mannose , isoelectric point , isoelectric focusing , amino acid , microbiology and biotechnology , larva , botany , enzyme
The immune protein, scolexin, a bacteria‐induced, larva‐specific protein from Manduca sexta , was shown to exist in the hemolymph in two isoelectric forms designated herein as scolexin‐1 and scolexin‐2 (native M r ∼ 72 kd). These two charge isomers appeared to share the same amino acid composition. Scolexin is composed of two subunits (peptide M r ∼ 36 kd) that possess the same N‐terminus. Scolexin‐2 was subjected to glycosyl composition analysis, revealing the presence of galactose, glucose, mannose, xylose, and sialic acid residues. Hybridization of epidermal RNA with oligonucleotides deduced from the scolexin N‐terminal sequence showed a continuous decline in mRNA following day 0 of the 5th larval instar. By employing in vitro protein labelling, it was found that organ cultures of the epidermis from immune larvae showed a greater ability over that of naive epidermal cultures to synthesize scolexin; these data reflected the inducible response seen in the hemolymph, and confirm other data indicating that the epidermis is an important site of scolexin biosynthesis. © 1995 Wiley‐Liss, Inc.