The
lin-3 -
let-60 interval of the right arm of chromosome IV contains thirteen essential gene mutations and 22 overlapping sequenced cosmids. The Sanger Center has nearly finished sequencing the entire interval. Analysis of cosmid sequences shows over one hundred potential coding regions. Of the coding regions with proposed protein function, more than 50% have strong homology to human genes. Most notably, the putative genes include three phosphatases, four protein kinases, a kinesin, and a cluster of histones. C. elegans strains carrying sequenced cosmids (in extrachromosomal arrays) have been constructed (see abstract for D. Janke et al., this meeting) and will be used in rescue experiments involving the essential genes in this interval.
lin-3 and
let-60(ras), the two genes bracketing this interval, were previously placed on the physical map by others. One of the remaining eleven essential genes has been already positioned to a cosmid:
let-70(
ubc2) (in collaboration with Mei Zhen and Peter Candido). By the time of the meeting, we anticipate that several of the remaining mutations will have been positioned to cosmids. This work is being funded by a grant from the Medical Research Council to Ann Rose and David Baillie and by a grant from the Natural Sciences & Engineering Research Council to David Baillie.