Worm Breeder's Gazette 10(2): 84

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.

A lin-12 Homolog

John Yochem and Iva Greenwald

Figure 1

We have isolated clones from a genomic library of N2 that cross-
hybridize at reduced stringency with probes from the lin-12 gene.  We 
sent one of the genomic clones, which had been partially sequenced to 
confirm that it did indeed contain a lin-12 related gene, to Alan 
Coulson and John Sulston, who located the sequence on the physical map 
just to the right of lin-12 by fingerprinting.  The combination of map 
position and sequence data made us very suspicious that the cloned 
sequence might correspond to glp-1, a gene that, like lin-12, has been 
implicated in cell-cell interactions (Austin and Kimble, 1987; Priess 
et al., 1987).  We sent the clone to Judith Austin and Judith Kimble, 
who had at about the same time by Southern blot analysis found glp-1 
allele alterations associated with cosmids in the region, and they 
then provided convincing evidence that our new sequence does 
correspond to the glp-1 gene (see their article in this Newsletter).  
We also sent the clone to Andy Fire, who had been microinjecting 
cosmid DNA from the region in collaboration with Jim Priess (see his 
article in this Newsletter).
DNA sequencing of both genomic and cDNA clones reveals a predicted 
glp-1 product that is 50-60% identical with lin-12 over extensive 
regions.  Like lin-12, the new sequence contains both EGF-like and 
nonEGF-like cysteine repeats in the predicted extracellular part of 
the protein as well as another repeated motif (also found in cdc10, 
SWI6 and Notch ) in the presumed cytoplasmic portion .  For example, 
we compare in the Figure part of the sequence encoded within a 
restriction fragment identified by Austin and Kimble as containing glp-
1 allele alterations with part of the ORF A exon of lin-12 (an exon 
containing EGF-like repeats).  These and more extensive sequence data 
not shown here suggest that lin-12 and glp-1 evolved from a common 
ancestor by gene duplication.  Perhaps other developmentally important 
genes are members of this family.
[See Figure 

Figure 1