GFP tagging of budding yeast chromosomes reveals that protein–protein interactions can mediate sister chromatid cohesion

摘要: Abstract Background Precise control of sister chromatid separation is essential for the accurate transmission genetic information. Sister chromatids must remain linked to each other from time DNA replication until onset chromosome segregation, when linkage be promptly dissolved. Recent studies suggest that machinery responsible destruction mitotic cyclins also degrades proteins play a role in maintaining linkage, and this regulated by spindle-assembly checkpoint. Studies on these problems budding yeast are hampered inability resolve its chromosomes light or electron microscopy. Results We have developed novel method visualizing specific sequences fixed living cells. A tandem array 256 copies Lac operator integrated at desired site genome detected binding green fluorescent protein (GFP)–Lac repressor fusion expressed HIS3 promoter. Using method, we show segregation precedes cyclin B. In mad bub cells, which lack checkpoint, can occur absence microtubules. The expression tetramerizing form GFP–Lac repressor, bind operators two different molecules, hold together under conditions they would normally separate. Conclusions conclude microtubule-dependent forces, complexes molecules capable holding together.