Proteins controlling sister-chromatid cohesion

Prior to the metaphase/anaphase transition of cell division the replicated copies of each chromosome, the sister chromatids, are attached to each other. We use the term ‘sister-chromatid cohesion’ to describe this physical association between the sister chromatids. Sister-chromatid cohesion is essential in mitosis to ensure that sister chromatids attach to microtubules from opposite spindle poles. Thus when segregation occurs, each daughter cell receives one copy of each chromosome.