Worm Breeder's Gazette 12(1): 40 (September 1, 1991)

These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.

The C-terminus of unc-6

William Wadsworth[1], Naoaki Ishiit[2], Edward Hedgecock[1]

Figure 1

[1]Johns Hopkins University, Baltimore, MD
[2]Tokai University School of Medicine, Japan.

unc-6 is required for guiding cell and axon migrations along the body wall. Previously, it was reported that the N-terminus of the protein is homologous to domains VI, V-1, V-2, and V-3, of laminin subunits. However, as discussed at the last C. elegans meeting, it was suspected that unc-6 is not a C. elegans homolog of a laminin subunit. We also reported that the genomic sequence downstream from the domain V-3 coding region did not predict exons that could encode laminin sequences.

The complete sequence of unc-6 has now been confirmed by sequencing PCR amplified cDNAs (we thank A. Fire for poly-A/adaptor primers). As shown below, the C-terminus is encoded by 5 exons. An untranslated region of 520 bp contains a polyadenylation signal MTMA 16bp upstream from the poly-A tract.

The C-terminus of unc-6 contains 153 amino acids ( unc-6 = 591 amino acids) and forms a unique domain designated C. The region contains six cysteines which could either form disulfide bonds to stabilize a folded structure or bind it to other proteins. Database searches have not revealed any strong homologies between domain C and other proteins. There is no homology to laminin. A modest similarity, of uncertain significance, is seen to the C-terminus of complement components C3 , C4 ,and C5 .

[See Figure 1]

Figure 1