Worm Breeder's Gazette 16(3): 21 (June 1, 2000)

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.

Possible perils pertaining to the lin-31 promoter and Pn.p cells

Meera Sundaram, Nathaniel R. Dudley

Dept. of Genetics, University of Pennsylvania School of Medicine, Philadelphia PA 19104

Studies of vulval development would be greatly aided by the availability of promoters that drive gene expression specifically in vulval precursor cells (VPCs). One not quite VPC-specific but still useful promoter is that of the lin-31 gene (Tan et al., 1998). P. Tan and S. Kim generously provided us with the PB255 version of the lin-31 promoter, which drives heterologous gene expression in Pn.p cells (including the VPCs) and a limited number of additional cells (mostly neurons). We have been using this promoter ("plin-31") to drive the vulval expression of various ksr-1 variants (*), and as a control, we have also analyzed a plin-31::GFP transgene. When injected into N2 at concentrations of 50-100 ng/µl, these transgenes donít have many obvious detrimental effects. However, we find that integrated arrays of our experimental and control transgenes sometimes cause a bar-1-like phenotype (Eisenmann et al., 1998) in which some VPCs never divide but rather adopt a "quaternary" or "fused" fate. The severity of this phenotype varies from line to line, but can be quite strong in some cases (e.g. one plin-31::KSR-1* line had 88% abnormal animals, n=36). Since we also see a weak bar-1 like phenotype in a control plin-31::GFP line (9% abnormal animals, n=22), we suspect that this phenotype could have less to do with ksr-1 than with high levels of lin-31 regulatory sequences (perhaps titrating out other factors such as BAR-1 or LIN-39). We advise other users to be cautious in interpreting similar defects caused by other plin-31 constructs.

 

Tan et al. (1998). Cell 93, 569-580.

Eisenmann et al. (1998). Development 125, 3667-3680.