Mutations in the Caenorhabditis elegans
rol-3 gene affect gross morphology in a manner similar to those in known cuticle collagen genes such as
rol-6 and
sqt-1. Specifically, worms homozygous for recessive visible mutations in
rol-3 (
e754 or
e202) display left-hand twisted cuticles, musculature and ventral nerve cords. In contrast to
rol-6 and
sqt-1, the majority of mutations in
rol-3 are associated with a recessive lethal phenotype. We are attempting to correlate the genetic and physical maps within the
rol-3 region to aid in placing the
rol-3 gene on the physical map, and ultimately determine the molecular nature of
rol-3. Initially, PCR was employed to provide an anchor between the physical and genetic maps in the
rol-3 region. Subsequent to this, we have generated a number of cosmid containing transgenic animals and have used these in attempts to rescue mutations within essential genes throughout the region. To date we have rescued 12 genes in the
rol-3 region. In an attempt to establish the function of
rol-3 in development we have characterized recessive intergenic suppressers of the
rol-3(
s1040)ts mid-larval lethal phenotype. These suppresser mutations define two complementation groups,
srl-1(II) and
srl-2(III). We have demonstrated that
srl-2(III)'s recessive suppression of
rol-3 lethality is not allele specific. Three factor mapping of
srl-2 places it close but to the right of
sma-3, covered by sDp8 and within the deficiencies sDf127 and sDf135. PCR mapping was instrumental in anchoring the endpoints of some LGIII deficiencies to the physical map thus revealing a physical interval within which
srl-2 was likely to reside (see abstract by N. Franz et al.). Using a small set of the LGIII cosmid transgenic library known to constitute a minimally overlapping span of contiguous cosmid clones (see abstract by D. Janke et al.) we were able to show that
srl-2 likely resides within the overlap region of the cosmids B0361 and F56C9. This work was supported by a Medical Research Council studentship to WBB and grants from NSERC to DLB and CGAT to A. Rose and DLB.