Cec-1,a Soma-Specific Chromobox-Containing Gene inC. elegans

Abstract

The chromo 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 ofDrosophila.The specific function of the chromo domain is not yet understood, but it seems to be required for protein–protein interactions in chromatin-associated complexes. Here, we present a new chromobox-containing gene fromCaenorhabditis elegans(cec-1). It encodes a nuclear protein that is present in all somatic cells from the 50- to 80-cell stage on throughout development and in adult animals. Nocec-1protein was detected in the cells of early embryos, in germ cells, and in their precursor cells Z2 and Z3.cec-1mRNA, however, is already present in all the blastomeres of early embryos. Immunolocalization experiments revealed a homogeneous distribution of CEC-1 within interphase nuclei, while during mitosis CEC-1 seems to dissociate from the condensing chromosomes. The expression pattern of thecec-1gene suggests that it may represent a new regulatory gene inC. elegans.