Project description:Long non-coding RNAs are important regulators of diverse biological prosesses. Here, we report on functional identification and characterization of a novel long intergenic noncoding RNA with MyoD-regulated and skeletal muscle-restricted expression that promotes the activation of the myogenic program, and is therefore termed Linc-RAM (Linc-RNA Activator of Myogenesis). Linc-RAM is transcribed from an intergenic region of myogenic cells and its expression is upregulated during myogenesis. Notably, in vivo functional studies show that Linc-RAM knockout mice display impaired muscle regeneration due to differentiation defect of satellite cells. Mechanistically, Linc-RAM regulates expression of myogenic genes by directly binding MyoD, which in turn promotes the assembly of the MyoD-Baf60c-Brg1 complex on the regulatory elements of target genes. Collectively, our findings reveal the functional role and molecular mechanism of a lineage-specific Linc-RAM as a regulatory lncRNA required for tissues-specific chromatin remodeling and gene expression.
Project description:mRNA cap addition occurs early during RNA pol II transcription, facilitating pre-mRNA processing and translation. We report that the mammalian mRNA cap methyltransferase, RNMT-RAM, promotes RNA pol II transcription, independently of mRNA capping and translation. In cells, sub-lethal suppression of RNMT-RAM reduces RNA pol II occupancy, net mRNA synthesis and pre-mRNA levels. Conversely, expression of RNMT-RAM increases transcription independently of cap methyltransferase activity. In isolated nuclei, recombinant RNMT-RAM stimulates transcriptional output; this requires the RAM RNA-binding domain. RNMT-RAM interacts with nascent transcripts along their entire length and with transcription associated factors including RNA pol II subunits, SPT4, SPT6 and PAFc. Suppression of RNMT-RAM inhibits transcriptional markers including histone H2B K120 ubiquitination, H3 K4 and K36 methylation, RNA pol II S5 and S2 phosphorylation and PAFc recruitment. These findings suggest that multiple interactions between RNMT-RAM, RNA pol II factors and RNA along the transcription unit stimulate transcription.
Project description:We investigated the role of RNMT and its cofactor RAM in T cells using conditional knockout mouse models. We demonstrate that RNMT and RAM have broadly overlapping roles in CD4 T cell activation.
