Abstract: Provided herein are compositions and methods for real-time identification and isolation of base-edited cell populations. Also provided herein are methods for producing enriched isogenic lines of genetically modified cells, including base-edited human pluripotent stem cells. In particular, provided herein are methods utilizing transient expression of reporter proteins, the detectable signal of which is altered following base editing. Using the transient reporter with a base editor permits enrichment of isogenic populations of base-edited cells.

Abstract: Compositions and methods relating to synthetic modification of histone-binding proteins. Some histone-binding fusion-protein compositions include a modified polycomb chromodomain (PCD) motif, for example two tandem copies of the H3K27me3-binding PCD at the N-terminus separated by a linker. Some methods relate to multivalent engagement of one or more histone proteins or to tuning the activity of a synthetic histone-binding transcriptional regulator, for example by contacting the one or more histone proteins with a histone-binding fusion-protein composition having a modified PCD motif.