THE FIRST ISOLATED COLLAGEN GENE OF THE ROOT-KNOT NEMATODE MELOIDOGYNE-JAVANICA IS DEVELOPMENTALLY-REGULATED

The nematode's surface comprises a multilayered cuticle, which consist s mainly of collagen proteins. We identified, cloned and characterized the first cuticular collagen gene, Mjcol-3, of the plant-parasitic ne matode Meloidogyne javanica. The gene putatively encodes a 32.4-kDa co llagen protein, including a propeptide which possesses a subtilisin-li ke protease-cleavage site. Six introns were identified in the gene seq uence, with three slightly different acceptor-splicing sites. The basi c structure of the predicted MJCOL-3 protein sequence is highly simila r to that of the Caenorhabditis elegans DPY-7, with 65.9% identity bet ween the two amino acid sequences. Relative to DPY-7, the putative MJC OL-3 protein has a shorter carboxy-terminus. This non-conserved featur e may indicate different contributions of DPY-7 and MJCOL-3 collagens to the structure of the cuticle. Mjcol-3 is developmentally regulated: transcripts were found mainly in preparasitic developing eggs, less i n parasitic third-and fourth-stage juveniles and young females shortly after the fourth molt, and much less in females before egg-laying. (C ) 1997 Elsevier Science B.V.