Exploration of DNA methylation in the chromatin of Triatoma infestans (Klug)

Sodium valproate (VPA) is an epidrug that inhibits histone deacetylases and favors histone acetylation and DNA demethylation, thereby inducing chromatin remodeling in several cell types. Although VPA induced heterochromatin decondensation in the hemipteran Triatoma infestans, this phenomenon was not favored by histone acetylation. Considering that DNA demethylation leading to chromatin unpacking is another consequence of VPA action in several organisms, we used immunofluorescence to investigate whether cytosine methylation was the target of VPA action that affected heterochromatin remodeling in T. infestans. In addition, Fourier transform infrared (FTIR) analysis was used to evaluate the participation of cytosine in T. infestans DNA. Immunofluorescence results indicated the absence of 5-methylcytosine signals in heterochromatin, but the presence of these signals in euchromatin, where demethylation was promoted by VPA. The FTIR spectra of T. infestans global DNA exhibited marks indicative of AT richness and a low representation of cytosine contribution. In conclusion, the chromatin remodeling event previously reported in the heterochromatin compartment of T. infestans in response to VPA, which was not due to histone acetylation, was also not due to DNA cytosine demethylation.