Worm Breeder's Gazette 15(3): 30 (June 1, 1998)

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.

Sequence changes associated with useful lin-12 mutations

Chenhui Wen1, E. Jane Albert Hubbard1,2, Richard Ruiz1, Iva Greenwald1

1 Dept. of Biochemistry and HHMI, Columbia University College of Physicians and Surgeons, NY, NY 10032
2 Current address: Dept. of Biology, NYU, NY, NY 10003 

        lin-12(n941) is an EMS-induced lin-12 allele that our lab uses
as the canonical null allele for genetic studies.   This allele contains
an amber stop codon in the eighth EGF-like motif  (amino acid W400STOP).
This observation suggests that lin-12(n941) is a molecular null allele. 
lin-12(n941) causes a highly penetrant 2 AC defect and other cell fate
transformations as described in Greenwald et al. (1983).   Note that in
the presence of smg-1, the lin-12(n941) allele causes an embryonic
lethal phenotype, probably as a result of a dominant-negative effect of
the truncated extracellular domain (Hilary Wilkinson, personal
communication.)   

        lin-12(n302ar220) behaves like a null allele; it contains a
UV/TMP-induced lesion, ar220, a small deletion in the extracellular
domain that creates a frameshift mutation in the fourth EGF-like motif. 
We have not examined the effect of smg-1 on this allele.    

        lin-12(n676n930) is an EMS-induced hypomorphic allele that we
have used for many genetic studies in our lab.  This allele contains a
missense mutation in the second EGF-like repeat (amino acid C138Y).  
The genetic properties of this allele have been described in detail in
Sundaram and Greenwald (1993a).

        Sequence changes associated with lin-12(n302), lin-12(n676) and
most other lin-12(d) mutations were published in Greenwald and Seydoux
(1990).