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MicroRNA-449 and microRNA-34b/c function redundantly in murine testes by targeting E2F transcription factor-retinoblastoma protein (E2F-pRb) pathway.

MicroRNAs (miRNAs) mainly function as post-transcriptional regulators and are involved in a wide range of physiological and pathophysiological processes such as cell proliferation, differentiation, apoptosis, and tumorigenesis. Mouse testes express a large number of miRNAs. However, the physiological roles of these testicular miRNAs remain largely unknown. Using microarray and quantitative real time PCR assays, we identified that miRNAs of the microRNA-449 (miR-449) cluster were preferentially expressed in the mouse testis, and their levels were drastically up-regulated upon meiotic initiation during testicular development and in adult spermatogenesis. The expression pattern of the miR-449 cluster resembled that of microRNA-34b/c (miR-34b/c) during spermatogenesis. Further analyses identified that cAMP-responsive element modulator τ and SOX5, two transcription factors essential for regulating male germ cell gene expression, acted as the upstream transactivators to stimulate the expression of the miR-449 cluster in mouse testes. Despite its abundant expression in testicular germ cells, miR-449-null male mice developed normally and exhibited normal spermatogenesis and fertility. Our data further demonstrated that miR-449 shared a cohort of target genes that belong to the E2F transcription factor-retinoblastoma protein pathway with the miR-34 family, and levels of miR-34b/c were significantly up-regulated in miR-449-null testes. Taken together, our data suggest that the miR-449 cluster and miR-34b/c function redundantly in the regulation of male germ cell development in murine testes.

Pubmed ID: 22570483


  • Bao J
  • Li D
  • Wang L
  • Wu J
  • Hu Y
  • Wang Z
  • Chen Y
  • Cao X
  • Jiang C
  • Yan W
  • Xu C


The Journal of biological chemistry

Publication Data

June 22, 2012

Associated Grants

  • Agency: NICHD NIH HHS, Id: HD050281
  • Agency: NICHD NIH HHS, Id: HD060858

Mesh Terms

  • Animals
  • Cell Cycle
  • Cell Proliferation
  • E2F Transcription Factors
  • Gene Expression Regulation, Developmental
  • HEK293 Cells
  • HeLa Cells
  • Humans
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • MicroRNAs
  • RNA Processing, Post-Transcriptional
  • Retinoblastoma Protein
  • Spermatogenesis
  • Testis