Heterochromatin protein 1 (HP1) proteins do not drive pericentromeric cohesin enrichment in human cells.
Sister chromatid cohesion mediated by cohesin is essential for accurate chromosome segregation. Classical studies suggest that heterochromatin promotes cohesion, but whether this happens through regulation of cohesin remains to be determined. Heterochromatin protein 1 (HP1) is a major component of heterochromatin. In fission yeast, the HP1 homologue Swi6 interacts with cohesin and is required for proper targeting and/or stabilization of cohesin at the centromeric region. To test whether this pathway is conserved in human cells, we have examined the behavior of cohesin in cells in which the levels of HP1 alpha, beta or gamma (the three HP1 proteins present in mammalian organisms) have been reduced by siRNA. We have also studied the consequences of treating human cells with drugs that change the histone modification profile of heterochromatin and thereby affect HP1 localization. Our results show no evidence for a requirement of HP1 proteins for either loading of bulk cohesin onto chromatin in interphase or retention of cohesin at pericentric heterochromatin in mitosis. However, depletion of HP1gamma leads to defects in mitotic progression.
Chromosome Dynamics Group, Molecular Oncology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain.
Angel
A
Serrano
Miriam
M
Rodríguez-Corsino
Ana
A
Losada
D018797:Cell Cycle Proteins / Q000378:metabolism*; D002503:Centromere; D000090266:Chromobox Protein Homolog 5; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D005455:Fluorescent Antibody Technique; D055785:Gene Knockdown Techniques; D006367:HeLa Cells; D006801:Humans; D047468:Immunoprecipitation; D011485:Protein Binding; D034741:RNA, Small Interfering; D000097722:Cohesins
D018797:Cell Cycle Proteins; D000090266:Chromobox Protein Homolog 5; D002868:Chromosomal Proteins, Non-Histone; D034741:RNA, Small Interfering; D000097722:Cohesins