INCREASED CHROMOKINESIN IMMUNOREACTIVITY IN RETINOBLASTOMA CELLS

chromokinesin is a developmentally down-regulated gene with specific e xpression in proliferating cells during embryonic chick development. I t encodes a DNA-binding motor protein localized along the chromosome a rm during mitosis, suggesting that the protein may be a component of t he long-observed, yet poorly understood 'ejection force' hypothesized to be involved in controlling the direction and speed of chromosome mo vement. We have isolated human chromokinesin; with affinity-purified a ntibodies we demonstrated immunocytochemically that Chromokinesin was present at a much higher level in cultured retinoblastoma cells than i n primary cultures of human dermal fibroblasts. The increase in immuno reactivity was particularly prominent in interphase cells, whereas in primary cultures of fibroblasts immunopositive cells were predominantl y M-phase cells. These observations imply a deregulation of chromokine sin in retinoblastoma cells. Data presented here may be useful in desi gning strategies to modulate chromosome movement and cell proliferatio n with either antisense oligonucleotides or specific antibodies, and h ence may set the stage for further investigations of the involvement o f chromosome motor molecules in mitosis under normal and pathological conditions. (C) 1997 Elsevier Science B.V.