CENTROMERIC PROTEIN-B NULL MICE ARE VIABLE WITH NO APPARENT ABNORMALITIES

The centromere protein B (CENP-B) is a centromeric DNA/binding protein . It recognizes a 17-bp sequence motif called the CENP-B box, which is found in the centromeric region of most chromosomes. It binds DNA thr ough its amino terminus and dimerizes through its carboxy terminus. CE NP-B protein has been proposed to perform a vital role in organizing c hromatin structures at centromeres. However, other evidence does not a gree with this view. For example, CENP-B is found at inactive centrome res on stable dicentric chromosomes, and also mitotically stable chrom osomes lacking a-satellite DNA have been reported. To address the biol ogical function of CENP-B,we generated mouse null mutants of CENP-B by homologous recombination. Mice lacking CENP-B were viable and fertile , indicating that mice without CENP-B undergo normal somatic and germl ine development. Thus, both mitosis and meiosis are able to proceed no rmally in the absence of CENP-B. (C) 1998 Academic Press.