Worm Breeder's Gazette 13(1): 49 (October 1, 1993)

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.

Cloning of the lin-32 Gene

Connie Zhao and Scott W. Emmons

The gene lin-32 is required for the expression of the ray sublineage leading to the
generation of rays in the C. elegans male tail. lin-32 functions in specifying
neuroblast cell fate: loss-of-function mutations cause the transformation of ray
neuroblast cells into hypodermal cells. The strongest allele of lin-32 , u282 ,also affects
the generation of certain touch neurons. We are in the process of cloning the lin-32
gene. We have identified a 5kb genomic fragment that rescues both ray-loss and
touch-insensitivity of lin-32 mutations.
  lin-32 maps on the X-chromosome between dpy-3 and unc-2 .Until recently,
there were no physical markers available in that region. Therefore, in order to clone
the lin-32 gene, we identified a Tc1 -associatedRFLP, bxP5 ,between two strains of C.
elegans, Bristol and Bergerac. bxP5 is closely linked to lin-32 mapping between lin-32
and unc-2 in a three-factor cross. We cloned the flanking region of bxP5 and located it
on the cosmid C04C8 .Recently, Donna Albertson mapped unc-2 to the left of Y5E3 by in
situ hybridization (1). Assuming that there is a linear relationship between the
physical map and the genetic map in that region, this allowed us to place lin-32 into a
small region covered by four cosmids: ZC391 , AH9 , T10H10 ,and C04C8 . A
Subsequent transformation experiment showed that ZC391 rescued a lin-32 mutation.
By generating a series of deletions and subcloning, we identified a 5kb genomic
fragment that still rescued lin-32 .We are now in the process of characterizing cDNA
clones and sequencing the lin-32 gene.
 (1) D.G.Albertson (1993) Genetics 134:211-219