Worm Breeder's Gazette 12(2): 41 (January 1, 1992)

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.

Molecular Cloning of unc-101

Junho Lee, Paul Sternberg

Figure 1

HHMI, Division of Biology, Caltech, Pasadena, CA 91125

The mutations of unc-101 confer pleiotropic phenotypes, including uncoordination, suppression of the vulval defect of lin-2 , lin-7 , lin-10 and weak let-23 alleles such as sy1 ,subviability, a male spicule defect, a FITC staining defect (E. Hedgecock) and a defecation defect (J. Thomas).

We characterized some phenotypes of the putative null allele ( sy216 )of unc-101 . sy216 ,which was induced by trimethyl psoralen, is homozygous lethal. Animals of the genotype unc-101 ( sy216 )/ unc-101 ( sy108 )are less viable than animals bearing sy108 in trans to any visible allele. Therefore, we believe that lethality is the null phenotype of unc-101 . sy216 / sy108 heterozygotes suppress let-23 ( sy1 )as efficiently as but not more than sy108 / sy108 homozygotes. This indicates that the suppression of let-23 ( sy1 )is also a null phenotype of unc-101 .

We have cloned the unc-101 gene. We isolated two Tc1 polymorphisms (TCUNC101A and TCUNC101 E)by inverse PCR of recombinants from unc-75 ( n950 ) ced-1 ( n1506 )+ unc-59 ( e261 )/ ++ unc-101 ( sy108 )+ heterozygous congenic strain (provided by S. Glass). TCUNC101 Ahybridized to a YAC which overlaps the TCCED1 YAC. TCUNC101 Ewas assigned to three overlapping YACs that are about 600 kb away from TCUNC101 A. TCUNC101 Ewas genetically mapped by southern hybridization or single worm PCR and found to be inseparable from unc-101 marker in 74 recombinants. Therefore, this polymorphism is very close to unc-101 (within + 0.5 m.u. with 95 % confidence). We tested the cosmids around TCUNC101 Epolymorphism for their ability to rescue the Unc phenotype of unc-101 ( sy108 ).Injection of W05A3 ,but not T27F6 rescued the Unc phenotype. We have narrowed the rescuing capability to a 7.3 kb subclone. This 7.3 kb subclone also rescues at least two other unc-101 phenotypes, the FITC staining defect and suppression of let-23 ( sy1 ).We have obtained a cDNA clone and the determination of sequence is underway.

[See Figure 1]

Figure 1