Furthermore, regulation of histone trimethylation or DNA methylation-hydroxymethylation by intravitreal administration of SuvH39H1-siRNA or Dnmt1-siRNA, soon after induction of diabetes, prevents increase in Rac1 gene transcripts, further supporting a close cross-talk between histone methylation and DNA methylation in regulating Rac1 transcription. The gene discussed is DNMT1; the disease is diabetes mellitus.