MicroRNA Mirn122a Reduces Expression of the Posttranscriptionally Regulated Germ Cell Transition Protein 2 (Tnp2) Messenger RNA (mRNA) by mRNA Cleavage1

Abstract

MicroRNAs play important roles in regulating development at both transcriptional and posttranscriptional levels. Here, we report 29 microRNAs from mouse testis that are differentially expressed as the prepubertal testis differentiates to the adult testis. Using computational analyses to identify potential microRNA target mRNAs, we identify several possible male germ cell target mRNAs. One highly conserved sequence in the 3'-untranslated region (UTR) of transition protein 2 (Tnp2) mRNA, a testis-specific and posttranscriptionally regulated mRNA in postmeiotic germ cells, is complementary to Mirn122a. Mirn122a is enriched in late-stage male germ cells and is predominantly on polysomes. Mirn122a, but not another noncomplementary microRNA, inhibits the activity of a luciferase reporter construct containing the 3'-UTR of Tnp2. Site-directed mutations of Mirn122a indicate that base pairing of the 5'-region of Mirn122a to its complementary site in the 3'-UTR of Tnp2 mRNA is essential for the downregulation of luciferase activity. Real-time reverse transcription-polymerase chain reaction and ribonuclease protection assays reveal that the Mirn122a-directed decrease of the Tnp2 reporter gene activity results from mRNA cleavage. We propose that specific microRNAs, such as Mirn122a, could be involved in the posttranscriptional regulation of mRNAs such as Tnp2 in the mammalian testis.

TBHP-induced oxidative stress alters microRNAs expression in mouse testis

“…MiR-122a is predominately expressed in adult stage male germ cells and it degrades the Transition Protein 2 (TNP2) transcript which is a testis-specific gene involved in chromatin remodeling during mouse spermatogenesis [58]. Over-expression of miR-122a could lead to mitotic arrest and apoptosis of spermatocytes [30] which is in agreement with the histopathology results of this study.…”

“…[ 58,30] incompletely arrested. Also, the treated testes showed progressive degeneration, as well as association between Sertoli and germ cells was disrupted (Fig.…”

Three dysregulated miRNAs control kallikrein 10 expression and cell proliferation in ovarian cancer

“…The KLK10 mRNA expression levels showed only slight decrease after miRNA transfection ( Figure 7B). Decreased mRNA expression after miRNA transfection has been reported earlier (Lim et al, 2005;Yu et al, 2005;Nishi et al, 2009;Pan et al, 2009;Qu et al, 2009;Arora et al, 2010), and may be due to partial degradation of the KLK10 transcript or other indirect effects. Figure 4 Effect of transfection of miR-224 and miR-516a on luciferase activity as measured with the pMIR -KLK10.…”

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“…miR-34c and miRNA34b are important players in the later steps of spermatogenesis in germ cells [233] and differentiation of male germ cells [183]. The role of miR-122a that regulates Tnp2, a testis-specific gene involved in chromatin remodeling during spermatogenesis cannot be underscored [184,185]. Additionally, miR-17-92 cluster functions in the regulation of apoptosis and E2F-1 transcription factor during normal spermatogenesis [186].…”