Evidence for two vitellogenin-related genes in Leucophaea maderae: The protein primary structure and its processing
Article first published online: 13 NOV 2007
Copyright © 2007 Wiley-Liss, Inc.
Archives of Insect Biochemistry and Physiology
Volume 66, Issue 4, pages 190–203, December 2007
How to Cite
Tufail, M., Bembenek, J., Elgendy, A. M. and Takeda, M. (2007), Evidence for two vitellogenin-related genes in Leucophaea maderae: The protein primary structure and its processing. Arch. Insect Biochem. Physiol., 66: 190–203. doi: 10.1002/arch.20212
- Issue published online: 13 NOV 2007
- Article first published online: 13 NOV 2007
- Manuscript Accepted: 25 MAY 2007
- Manuscript Received: 15 MAR 2007
- Japan Society for the Promotion of Science (JSPS) Post Doctoral Fellowship for Foreign Researchers. Grant Number: P03114
- Leucophaea maderae;
We previously reported a cDNA for vitellogenin (Vg) from the cockroach, Leucophaea maderae (Lm). In the present study, we identified another cDNA encoding a second Vg (Vg2) having stretches of amino acid sequences different from the first one, Vg1, reported earlier. The complete nucleotide sequence of Vg2 consisted of 5,915 bp, which encoded a primary protein of 1,911 residues including a 16-residue putative signal peptide. The regions different in both Vg precursors (Pro-Vg1 and pro-Vg2) were four in number, and two, relatively longer, existed at the carboxy terminal. The presence of two Vg-related cDNAs was confirmed by sequencing of RT-PCR products generated using primers designed based on the common sequences flanking the regions different in amino acid sequences. Both forms were transcribed since they could be amplified on mRNA from fat bodies of different individual females. Southern blot analysis of digested genomic DNA revealed the existence of two Vg-related genes in L. maderae indicating that each Vg cDNA originated from a separate gene. Also, the immunoblot analysis using antibodies generated against peptides unique to both Vg1 and Vg2 probed the same antigen in the same individual, suggesting LmVg to be a product coded by two different Vg precursors. Both Vg primary products showed 96% similarity at an amino acid level. Compared to other insect Vgs, Vg2 showed a slightly higher (1–2%) similarity than Vg1. We previously reported, based on amino-terminal sequence analysis, that L. maderae pro-Vg was cleaved into four subunit polypeptides (112-, 100-, 92-, and 55-kD), which were deposited in the egg as four respective vitellin (Vn) polypeptides. We show now based on immunoblot analysis that the 112-kD polypeptide is further cleaved, near the C-terminus, to an 87-kD polypeptide before it is secreted into the hemolymph. Both the L. maderae Vgs were compared with each other and with other insect Vgs and the processing pattern is discussed. Arch. Insect Biochem. Physiol. 66:190–203, 2007. © 2007 Wiley-Liss, Inc.