miRNP:mRNA association in polyribosomes in a human neuronal cell line (original) (raw)

  1. PETER T. NELSON1,
  2. ARTEMIS G. HATZIGEORGIOU2,3,4, and
  3. ZISSIMOS MOURELATOS1
  4. 1Department of Pathology, 2Department of Genetics, and 3Center for Bioinformatics, School of Medicine, and 4Computer and Information Science, School of Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA

Abstract

MicroRNAs (miRNAs) are small regulatory RNAs that control gene expression by base-pairing with their mRNA targets. miRNAs assemble into ribonucleoprotein complexes termed miRNPs. Animal miRNAs recognize their mRNA targets via partial antisense complementarity and repress mRNA translation at a step after translation initiation. How animal miRNAs recognize their mRNA targets and how they control their translation is unknown. Here we describe that in a human neuronal cell line, the miRNP proteins eIF2C2 (a member of the Argonaute family of proteins), Gemin3, and Gemin4 along with miRNAs cosediment with polyribosomes. Furthermore, we describe a physical association between a let-7b (miRNA)-containing miRNP and its putative human mRNA target in polyribosome-containing fractions. These findings suggest that miRNP proteins may play important roles in target mRNA recognition and translational repression.

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