Worm Breeder's Gazette 15(1): 50 (October 1, 1997)
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.
Department of Molecular Genetics, Albert Einstein College of Medicine, 1300 Morris Park Ave. Bronx, NY 10461
During male ray development, seam cells send inhibitory signals to their neighbors to inhibit ray production. For example, seam cell T sends a signal to its anterior neighbor V6 to inhibit production of rays 2 through 6. pal-1, which encodes a homolog of Drosophila caudal, acts in V6 autonomously to override this inhibitory signal . To identify the signal from seam cell T, as well as other components which can bypass this inhibitory signal to allow V6 to produce rays 2 through 6, we performed a screen for suppressors of pal-1(e2091). 19 alleles defining 15 genes were obtained from 4000 genomes screened. We are trying to clone four of them: sop-1(bx92, bx93, bx104, bx107), sop-2(bx91), sop-3(bx96), and sop-4(bx106). sop-1 is located on the X chromosome, about +1.18. In the strongest allele, bx92, 97% of sides have normal V6 rays in pal-1 mutant background. Besides suppressing pal-1, sop-1 also can partially suppress mab-5(e1239); the rays in mab-5; sop-1 mutant are dependent on egl-5 activity. No other obvious phenotype has been observed. Recently, we cloned sop-1. It encodes a 3520 amino acid protein which contains transmembrane domain(s). It shows significant similarity to one uncharacterized human gene. A sop-1-GFP reporter gene has been constructed. Preliminary data shows it is expressed in the head region and in several tail cells in both sexes. Surprisingly, it seems to be in nucleus. sop-2 is mapped on chromosome II, about -19.32. In sop-2, 7% of male sides have rays 2 and 3 transformed to rays 4, 5, and 6. This suggests possible misregulation of egl-5 in the V6 lineage (see Ferreira, Zhang and Emmons, this issue). In some males there are several rays as well as fan-like cuticlular structures in the central body region. In 30% of hermaphrodites, alae are discontinuous. Besides suppressing pal-1, sop-2 also can suppress lin-32 (e1926 and u282). The sop-2 mutant has other phenotypes, including affects on vulval development. To determine whether these pleiotropic effects are due to ectopic expression of Hox genes, we are studying the Hox gene expression pattern in sop-2 mutant (many thanks to QueeLim Chng and Dr. Cynthia Kenyon for mab-5-lacZ, mab-5-GFP, lin-39-lacZ and egl-5-lacZ reporter genes). sop-3 is mapped on chromosome I: both tDf3 and tDf4 delete sop-3. The effect of sop-3 mutation is very similar to sop-1, both have maternal effect and partially suppress mab-5(e1239). In sop-3, there is a low frequency of ray fusion, and ray 6 is sometimes missing. The cosmids from this region have been requested to do transformation rescue. sop-4 is also located on chromosome I. It is close to unc-11, and the deficiencies and duplications from this region are being tested. In sop-4; pal-1 mutant, 71% of sides have normal V6 rays. sop-4 alone has no obvious phenotype. pal-1 is required for mab-5 expression in V6 , so we are using mab-5-lacZ and mab-5-GFP reporter genes to study whether mab-5 is expressed in a pal-1 background in sop-1, sop-2, sop-3, and sop-4 mutant.  Waring, D. A. & Kenyon, C Nature 350, 712-715; Cell 60, 123-131.  Salser, S. J. & Kenyon, C Development 122, 1651-1661.