Abstract
Project Title: Translational Control of Human Interleukin-3 Mediated by its 3’-Untranslated Region
Authors: Daisy D. Colón-López, Marimar Hernández-Pérez, José A. González-Feliciano and Carlos I. González Ph.D.
University: University of Puerto Rico – Río Piedras
Department: Department of Biology
Category: Molecular Biology
Abstract:
Human interleukin-3 (IL-3) is a cytokine that stimulates the growth and differentiation of early lymphoid stem cells and has been implicated in cancer. IL-3 is a member of a class of transiently expressed mRNAs that harbor Adenosine/Uridine-Rich Elements (ARE) in their 3’-UTRs. The 3’-UTRs of many cytokines play a role in post-transcriptional control by altering mRNA stability and/or translation. The regulatory effects of 3’UTR’s are often mediated by the interaction of specific cis-acting elements with trans-acting factors. To understand how the ARE sequences from the 3′-UTR of the hIL-3 are involved in controlling translation, we conducted a site-directed mutagenesis analysis of the four AREs clusters recently identified in the hIL-3 3’UTR. Firefly luciferase reporter chimeras harboring specific ARE mutations were constructed and transfected into HeLa cells. Dual luciferase assays and quantitative Real Time-PCR were used to measure protein and mRNA levels, respectively. The results from this analysis demonstrate that mutations in the hIL-3 nonamer sequences, ARE2 and ARE3, affect the translational efficiency of the luciferase reporter chimeras. Our data further suggest an important role for these AREs in the translational control of hIL-3. Ongoing studies in the laboratory are focused on the identification and characterization of the trans-acting factors that interact with the ARE2 and ARE3 sequences in hIL-3 3’-UTR. Together, these studies can potentially provide powerful tools for regulating IL-3 gene expression and preventing certain types of cancer.
This work was supported by grants from the National Institutes of Health to C.I.G. (GM008102-3052, KO1 HL-04355-05, U54 CA96297-03, P20 RR 016174). M.H. is supported by the RISE Program (UPR-MSC). D.D.C.L. was supported by PRLS-AMP and is currently supported by the RISE Program (2 R25 GM061151) and BioMinds.
