Cohesin’s STAG subunits have redundant and nonredundant roles for 3D chromatin organization and transcription control. Homo sapiens

The cohesin complex has a major role for genome stability, 3D chromatin organization as well as differentiation and development. In somatic cells the cohesin complex exist in different “flavors” distinguished by the presence of either the SA1 subunit or the SA2 subunit in the complex. It is known that the two subcomplexes have distinct roles for the “classic” sister chromatid cohesion function of cohesin. Also, different types of developmental defects are associated with the complexes, plus a predominant involvement of SA2 in different cancer types. However, throughout the genome both subcomplexes colocalize, raising the question how they are involved in the chromatin organization and transcriptional regulation function of the cohesin complex. We investigated this by Hi-C, ChIP-sequencing and RNA-sequencing of cells with intact cohesin or one or the other STAG subunit depleted by auxin-mediated protein degradation.