CEC-1, A SOMA-SPECIFIC CHROMOBOX-CONTAINING GENE IN C-ELEGANS

The chrome domain is a phylogenetically conserved sequence motif which was identified as a region of homology between the repressor protein Pc and the heterochromatin constitutive protein HP1 of Drosophila. The specific function of the chromo domain is not yet understood, but it seems to be required for protein-protein interactions in chromatin-ass ociated complexes. Here, we present a new chromobox-containing gene fr om Caenorhabditis elegans (cec-1). It encodes a nuclear protein that i s present in all somatic cells from the 50- to 80-cell stage on throug hout development and in adult animals. No cec-1 protein was detected i n the cells of early embryos, in germ cells, and in their precursor ce lls Z2 and Z3. cec-1 mRNA, however, is already present in all the blas tomeres of early embryos. Immunolocalization experiments revealed a ho mogeneous distribution of CEC-1 within interphase nuclei, while during mitosis CEC-1 seems to dissociate from the condensing chromosomes. Th e expression pattern of the cec-1 gene suggests that it may represent a new regulatory gene in C. elegans. (C) 1996 Academic Press, Inc.