C/EBPb and Egr-1 coordinately regulate Chka expression during RA-induced neuronal differentiation.

DOMIZI, PABLO Y BANCHIO C

Mendoza

Congreso; SAIB; 2012

Neuritogenesis is a dynamic process, involving the generation and extension of long protrusions called neurites. This process is critically dependent on membrane biosynthesis. Phosphatidylcholine (PC) is the most abundant phospholipid in eukaryotic cells. During retinoic acid (RA) induced differentiation of neuroblastoma cells, the augmented PC synthesis is supported by the sequential expression of two enzymes of the Kennedy pathway: choline kinase (CK) and CDP:phosphocholine cytydilyltransferase alpha (CCTa). We are interested in delineating describing dilucidating identifying the mechanism by which RA induces the expression of Chka gene. Using promoter reporter assay, electromobility gel shift assay, analysis of point mutations and overexpression of different transcription factors we demonstrated that the region between -953 and -901 bp of Ckha promoter is essential for RA induction. This region contains  C/EBP and Egr binding sites which are implicated in Chka transcriptional induction. We demonstrated that C/EBPb overexpression promote Chka expression and stimulates neuronal differentiation even in the absence of RA, and we also observed that Egr is necessary for Chka response to RA. In summary, these results suggest that Chka regulation by RA is a complex mechanism in which the transcription factors C/EBPb and Egr participate together to induce expression of Chka.