Regulation of cyclin T1 and HIV-1 Replication by microRNAs in resting CD4+ T lymphocytes

J Virol. 2012 Mar;86(6):3244-52. doi: 10.1128/JVI.05065-11. Epub 2011 Dec 28.

Abstract

The replication of integrated human immunodeficiency virus type 1 (HIV-1) is dependent on the cellular cofactor cyclin T1, which binds the viral Tat protein and activates the RNA polymerase II transcription of the integrated provirus. The activation of resting CD4(+) T cells upregulates cyclin T1 protein levels independently of an increase in cyclin T1 mRNA levels, suggesting a translational repression of cyclin T1 in resting CD4(+) T cells. Hypothesizing that microRNAs (miRNAs) repress cyclin T1 translation in resting CD4(+) T cells and that this inhibition is lifted upon cell activation, we used microarray expression analysis to identify miRNAs miR-27b, miR-29b, miR-150, and miR-223 as being significantly downregulated upon CD4(+) T cell activation. The overexpression of these miRNAs decreased endogenous cyclin T1 protein levels, while treatment with the corresponding antagomiRs increased cyclin T1 protein levels. An miR-27b binding site within the cyclin T1 3' untranslated region (3'UTR) was identified and confirmed to be functional after the mutation of key resides abrogated the ability of miR-27b to decrease the expression of a luciferase reporter upstream of the cyclin T1 3'UTR. Ago2 immunoprecipitation revealed an association with cyclin T1 mRNA that was decreased following treatment with miR-27b and miR-29b antagomiRs. Cells overexpressing miR-27b showed decreased viral gene expression levels of the HIV-1 reporter virus and a decreased replication of strain NL4.3; a partial rescue of viral transcription could be seen following the transfection of cyclin T1. These results implicate miR-27b as a novel regulator of cyclin T1 protein levels and HIV-1 replication, while miR-29b, miR-223, and miR-150 may regulate cyclin T1 indirectly.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • CD4-Positive T-Lymphocytes / metabolism*
  • CD4-Positive T-Lymphocytes / virology
  • Cell Line
  • Cells, Cultured
  • Cyclin T / genetics*
  • Cyclin T / metabolism
  • Down-Regulation
  • HIV Infections / genetics*
  • HIV Infections / metabolism
  • HIV Infections / virology
  • HIV-1 / genetics
  • HIV-1 / physiology*
  • Humans
  • MicroRNAs / genetics
  • MicroRNAs / metabolism*
  • Protein Biosynthesis
  • Up-Regulation
  • Virus Replication*

Substances

  • Cyclin T
  • MicroRNAs