Epigenetic regulation of the micro RNA machinery

RÉ DELFINA A.; MANAVELLA PA

Foz do Iguaçu

Congreso; 11th International Congress of Plant Molecular Biology; 2015

Micro RNAs (miRNA) are 21 nucleotides molecules, essential for post-transcriptional gene regulation. These molecules are generated from a structured RNA precursor by DICER LIKE 1, HYPONASTIC LEAVES 1 and SERRATE and then incorporated into the RNA induced silencing complex (RISC) to specifically silence target genes? mRNAs.During the last years, new proteins have been identified and incorporated as part of the miRNA biosynthesis machinery. In our lab we have isolate novel mutants deficient in miRNA activity, from which important cofactors of the pathway, such as CPL1, RCF3 and the THO/TREX complex, have been discovered. Here we describe MIRNA-SILENCING SUPPRESSED 47 (mss47), a gene identified by our genetic screening that codifies a protein with a histone-methyltransferase domain. Small RNA blots and RT-qPCR showed that mss47 mutants present altered level of miRNAs and target-mRNAs. Analysis of the H3K27me3 profile in mss47 mutant plants revealed an altered histone methylation profile in several genes encoding miRNA-related factors. Measurements of the mRNA levels of these genes confirmed an abnormal expression in this mutant. According to these results, MSS47 regulates the expression of some crucial proteins in the miRNA pathway by epigenetic modification, what impacts in miRNA production and gene silencing.