Publication Date:
2016-12-01
Description:
Previous studies suggested that the aryl hydrocarbon receptor (AhR) contributes to mice reproduction and fertility. However, the mechanisms involved remain mostly unknown. Retrotransposon silencing by Piwi-interacting RNAs (piRNAs) is essential for germ cell maturation and, remarkably, AhR has been identified as a regulator of murine B1-SINE retrotransposons. Here, using littermate AhR +/+ and AhR −/− mice, we report that AhR regulates the general course of spermatogenesis and oogenesis by a mechanism likely to be associated with piRNA-associated proteins, piRNAs and retrotransposons. piRNA-associated proteins MVH and Miwi are upregulated in leptotene to pachytene spermatocytes with a more precocious timing in AhR −/− than in AhR +/+ testes. piRNAs and transcripts from B1-SINE , LINE-1 and IAP retrotransposons increased at these meiotic stages in AhR-null testes. Moreover, B1-SINE transcripts colocalize with MVH and Miwi in leptonema and pachynema spermatocytes. Unexpectedly, AhR −/− males have increased sperm counts, higher sperm functionality and enhanced fertility than AhR +/+ mice. In contrast, piRNA-associated proteins and B1-SINE and IAP -derived transcripts are reduced in adult AhR −/− ovaries. Accordingly, AhR-null female mice have lower numbers of follicles when compared with AhR +/+ mice. Thus, AhR deficiency differentially affects testis and ovary development possibly by a process involving piRNA-associated proteins, piRNAs and transposable elements.
Electronic ISSN:
2046-2441
Topics:
Biology
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