A RELATION BETWEEN ALTERNATIVE SPLICING CHOICES AND CHROMATIN STRUCTURE IN NEURONAL DIFFERENTIATION

ANA FISZBEIN; IGNACIO SCHOR; EZEQUIEL PETRILLO; ALBERTO R. KORNBLIHTT

Congreso; SAIB - XLVII Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2011

RNA polymerase II elongation rates modulate alternative splicing choices and affect the timing at which nascent pre-mRNA splice sites are presented to the spliceosome. This is relevant for regulation of endogenous alternative splicing events by dynamic changes in intragenic chromatin structure that could affect RNA processivity or elongation rate. Using the alternative exon 18 of the NCAM gene as a model, we have shown that neuronal differentiation triggers transcription-repressive intragenic histone modifications in the NCAM gene, correlating with an increase of its alternative exon 18 inclusion. This alternative exon inclusion determines the expression of the NCAM 180 isoform, typical of mature and stable synapses. We study this regulation using DMSO-induced differentiation of N2a cells, a murine neuronal cell line. Treatment of differentiated N2a cells with an inhibitor of DNA methylation or with a histone hyper-acetylating drug revert the effect of differentiation on the exon 18 inclusion. To extend the analysis to other alternative splicing events, we used available ChIP-seq data to search genes with correlated modulation of both histone marks and AS patterns during neuronal differentiation, and selected the Tcf7l2 and the fibronectin genes. This regulation represents an example of chromatin-dependent alternative splicing modulation associated with development.