H1° mRNA-containing complexes in rat brain cells. In: Proceedings of the Abstracts

Post-transcriptional regulation of gene expression depends on RNA-binding proteins (RBPs), which are able to regulate translation, stability and subcellular localization of mRNAs [1]. RNA-protein complexes start to be built up since transcription; some proteins remain then bound to the transcript, while others behave as only transient components. In the developing nervous system of mammals, the postnatal production of the histone variants H1° and H3.3 is mainly regulated at the post-transcriptional level. Synthesis and incorporation into chromatin of the two histone proteins has been suggested to be involved in the epigenetic regulation of gene expression, both in normal brain development and brain cancer. We previously identified a set of proteins which interact with mRNAs encoding H1° and H3.3 mRNA [2-5]. Recently, we demonstrated that these proteins are probably part of a ribonucleoprotein particle which contains both unspecific and specific RBPs [6]. Here we confirm, by affinity chromatography, the presence of Hsc70 chaperone in the complex and, in addition, we report that the complex is present not only in the nuclear extracts, as previously shown, but also in a membrane-containing cytoplasmic pellet, obtained by centrifugation at 105.000 x g (P105). In parallel, we demonstrated that sumoylated PIPPin, already found in neurons, is present also in the nuclei of cultured astrocytes. Finally, we found that two of the hnRNPs previously found in the complexes show a differential expression and localization during rat brain maturation. [1] Di Liegro CM et al. 2014, Int J Mol Med 33:747-62. [2] Scaturro M et al. 1998, J Biol Chem 273:22788-91. [3] Nastasi T et al. 1999, J Biol Chem 274:24087-93. [4] Sala A et al. 2007, Int J Mol Med 19:501-9. [5] Saladino P et al. 2012, Int J Mol Med 29:141-5 [6] Di Liegro CM et al. 2013, Neuroscience 229:71-6.