Background: G9a is the primary enzyme for mono- and dimethylation at Lys 9 of histone
H3 and forms predominantly the heteromeric complex as a G9a-GLP (G9a-like protein) that is a
functional histone lysine methltransferase in vivo. Mounting evidence suggests that G9a catalyzes
methylation of histone and nonhistone proteins, which plays a crucial role in diverse biological
processes and human diseases.
Methods: In this study, the current knowledge on biological functions of G9a and inhibitors were
Results: we review the current knowledge on biological functions of G9a, with particular emphasis
on regulating gene expression and cell processes, and involvement in human diseases. We outline a
perspective on various classes of G9a inhibitors to date from both articles and patents with an
emphasis on their discovery, activity and the current research status.
Conclusion: We highlight the key knowledge on potential biological functions and various human
diseases. We also reviewed the discovery and characterization of the reported G9a inhibitors. However,
we also propose the challenges and future opportunities in study of G9a. This review could
make a crucial contribution to the long journey to develop drug-like molecules targeting G9a.