The 3′ untranslated region of human Cyclin-Dependent Kinase 5 Regulatory subunit 1 contains regulatory elements affecting transcript stability

Abstract

Background: CDK5R1 plays a central role in neuronal migration and differentiation during central nervous system development. CDK5R1 has been implicated in neurodegenerative disorders and proposed as a candidate gene for mental retardation. The remarkable size of CDK5R1 3′-untranslated region (3′-UTR) suggests a role in post-transcriptional regulation of CDK5R1 expression. Results: The bioinformatic study shows a high conservation degree in mammals and predicts several AU-Rich Elements (AREs). The insertion of CDK5R1 3′-UTR into luciferase 3′-UTR causes a decreased luciferase activity in four transfected cell lines. We identified 3′-UTR subregions which tend to reduce the reporter gene expression, sometimes in a cell line-dependent manner. In most cases the quantitative analysis of luciferase mRNA suggests that CDK5R1 3′-UTR affects mRNA stability. A region, leading to a very strong mRNA destabilization, showed a significantly low half-life, indicating an accelerated mRNA degradation. The 3′ end of the transcript, containing a class I ARE, specifically displays a stabilizing effect in neuroblastoma cell lines. We also observed the interaction of the stabilizing neuronal RNA-binding proteins ELAV with the CDK5R1 transcript in SH-SY5Y cells and identified three 3′-UTR sub-regions showing affinity for ELAV proteins. Conclusion: Our findings evince the presence of both destabilizing and stabilizing regulatory elements in CDK5R1 3′-UTR and support the hypothesis that CDK5R1 gene expression is post-transcriptionally controlled in neurons by ELAV-mediated mechanisms. This is the first evidence of the involvement of 3′-UTR in the modulation of CDK5R1 expression. The fine tuning of CDK5R1 expression by 3′-UTR may have a role in central nervous system development and functioning, with potential implications in neurodegenerative and cognitive disorders. © 2007 Moncini et al; licensee BioMed Central Ltd.