Worm Breeder's Gazette 10(3): 39
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.
unc-6 was identified and cloned by Tc1 insertions in the first and third exons (Fig. 1). The first five exons encode a protein 44% identical to N-terminal domains VI and V of mouse laminin B2 (Sasaki and Yamada, JBC 262, 17111, 1987). As this is comparable to the similarity between mouse and insect laminin B2 chains (D. Montal and C. Goodman, pers. comm.), we have tentatively concluded that unc-6 encodes the nematode laminin B2 chain (1988 East Coast Meeting Abstracts). We thank A. Otsuka for performing the database search. Laminin B2 is specifically required for guiding circumferential (= dorsal/ventral) cell and axon migrations on the body wall. It acts in concert with the unc-5 and unc-40 products which may be cellular laminin receptors or laminin-associated matrix molecules. We speculate that laminin B1, and perhaps laminin A, are required for guiding longitudinal (= anterior/posterior) migrations on the body wall. We have sequenced 336 nucleotides upstream of the initiator ATG and have not found a TATAA box. There is a repeated TAT sequence about - 100 nt from the ATG start (Fig. 2). We have identified four repeated motifs in the upstream region: type 1 = TTtGCCTCT, type 2 = ttTGCATRc, type 3 = CCgcntTCCAC, and type 4 = GTCwATTTCC. The tandem type 2 repeats match 14/18 bp of the tandem sph motifs of the sv40 enhancer. [See Figure 1 & 2]