We have undertaken a molecular analysis of three genes to better understand the basic processes of nuclear migration in the context of cellular migrations during development. Mutations in two of these genes,
unc-84 and
unc-83 , block the nuclear migrations of hypodermal P cells, which normally migrate from a lateral position to the ventral cord, and of
hyp7 precursor cells, which normally elongate circumferentially across the dorsal midline (2, 3). Mutations in
unc-84 and
anc-1 disrupt the proper anchorage of hypodermal nuclei (1, 2).
unc-84 has been cloned and encodes for a novel protein with a predicted trans-membrane domain and a C-terminal domain with high similarity to the S. pombe spindle pole body component Sad1. An UNC-84:GFP protein is detected at the nuclear envelope (3). To confirm this finding, we are in the process of raising antibodies against UNC-84. We have further mapped
unc-83 on chromosome V and have obtained single cosmid rescue of the
hyp7 nuclear migration defect with the cosmid W01A11. We are currently attempting to rescue
unc-83 with subclones of W01A11. Finally, we are in the process of cloning
anc-1 . It has been linked to the physical map to the right of
unc-11 (which is within cosmid C32E8) and to the left of hDf7 (which has a left breakpoint in cosmid C24G7). We are currently injecting cosmids in this region. 1. Hedgecock, E. M., and J. N. Thomson. 1982. Cell . 30:321-330. 2. Malone, C. J., W. D. Fixsen, H. R. Horvitz, and M. Han. 1999. Submitted to Development . 3. Sulston, J., and H. R. Horvitz. 1981. Dev. Biol. 82:41-55.