In this new study, researchers identified a new CRL type E3 ligase ( which they termed CRL7SMU1) that has an essential role in chromatid cohesion maintenance. SMU1, DDB1, CUL7 and RNF40 were identified as main components of this new complex. SMU1 by acting as a substrate recognition module, binds to H2B and mediates monoubiquitination at K120 site through CRL7SMU1 E3 ligase complex. Depletion of CRL7SMU1leads to loss of H2B ubiquitination at SMC1a locus and thus subsequently compromised SMC1a expression in cells.The results from their study show an important role of CRL7SMU1 E3 ligase in promoting H2B ubiquitination for maintenance of sister chromatid cohesion during mitosis. The well-cited Bioruptor Pico was essential to shear chromatin to optimal lengths in this study.
