The human synMuv-like protein LIN-9 is required for transcription of G2/M genes and for entry into mitosis

Abstract

Regulated gene expression is critical for the proper timing of cell cycle transitions. Here we report that human LIN‐9 has an important function in transcriptional regulation of G2/M genes. Depletion of LIN‐9 by RNAi in human fibroblasts strongly impairs proliferation and delays progression from G2 to M. We identify a cluster of G2/M genes as direct targets of LIN‐9. Activation of these genes is linked to an association between LIN‐9 and B‐MYB. Chromatin immunoprecipitation assays revealed binding of both LIN‐9 and B‐MYB to the promoters of G2/M regulated genes. Depletion of B‐MYB recapitulated the biological outcome of LIN‐9 knockdown, including impaired proliferation and reduced expression of G2/M genes. These data suggest a critical role for human LIN‐9, together with B‐MYB, in the activation of genes that are essential for progression into mitosis.