Chromosome dynamics and Nuclear Motors – Chromobility
Chromosomes and genes sit in non-random locations inside the nuclei of individual cells. This strict organisation of the genome is controlled by nuclear structures found at the nuclear periphery, throughout the nucleoplasm and internally within the nuclei. We have mapped the position of all human chromosomes in proliferating and quiescent human dermal fibroblasts and have found that in proliferating cells chromosomes are organised according to their gene density and in quiescent cells their size. This means that there is dramatic re-positioning of specific chromosomes upon cells changing their proliferative status. We have shown previously that this relocalisation is rapid, active and directional and requires nuclear myosin 1b, a nuclear motor protein (Mehta et al., 2010).
Thus, we postulate that nuclear motors are present that move whole chromosomes to new locations in the cell nuclei and even individual genes. We are currently investigating what the other proteins are involved in the motor complex and what is required of chromatin to be relocated.