Document Type


Publication Date


Publication Title

The Journal of Biological Chemistry


Both cDNA and genomic DNA sequences have been isolated which encode a proline-rich precursor protein of the sheath from microfilariae, the first stage larvae of the filarial nematode parasites Brugia pahangi andBrugia malayi. This 22-kDa protein is soluble only under reducing conditions and is extensively cross- linked by both disulfide and nonreducible bonds. Immunogold electron microscopy shows that the protein is localized exclusively in the sheath, a vestigial remnant of the eggshell, which is retained by and encloses the mature microfilaria. Analysis by Western blotting confirms that the protein is expressed only in microfilariae and adult female worms, although transcripts are detectable only in adult females. The deduced amino acid sequence contains a short N-terminal hydrophobic putative leader sequence, a central repetitive domain that contains 14 copies of a degenerate 5-amino acid repeat with the consensus sequence Met- Pro-Pro-Gln-Gly, and a C-terminal prolinerich do- main flanked by clusters of cysteine residues. These clusters can be aligned with cysteine residues implicated in cross-linking of a family of cuticular collagens originally identified in Caenorhabditiselegans but which extends to other nematodes.





First Page


Last Page



©1991 The American Society for Biochemistry and Molecular Biology, Inc


Archived as published.

Included in

Biology Commons



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.