ISOLATION OF HUMAN NUMA PROTEIN

NuMA is a protein involved in maintenance of nuclear structure and in the assembly of the mitotic spindle. Expression of amino-terminal dele tion mutants results in a phenotype identical to that caused by a temp erature-sensitive defect of RCC1 (regulator of chromosome condensation ). Here we describe the isolation of NuMA protein from HeLa cells unde r mild conditions as a prerequisite to study its interactions with ele ments of the RCC1-Ran regulatory pathway. In an overlay assay, NuMA di d not bind Ran.[gamma-P-32]GTP. Thus it is clearly different from Ran. GTP binding proteins of similar M(1).