| Summary: | <p>Abstract</p> <p>Background</p> <p>The synthesis of microRNA (miRNA) is a multi-step process that requires the action of the ribonuclease Dicer1. Dicer1 is responsible for the final processing of miRNA and has been implicated in cellular processes such as proliferation, apoptosis, and differentiation. Mouse embryos lacking <it>Dicer1 </it>die in early embryogenesis. In this study, we investigated whether <it>Dicer1 </it>is required for development of adrenal, testis, and ovary in mouse embryos.</p> <p>Results</p> <p>To target <it>Dicer1 </it>deletion specifically in developing adrenals and gonads, we used Steroidogenic factor 1-cre (<it>Sf1/Cre</it>) line in which Cre recombinase is active in the progenitor cells of adrenals and gonads. Lack of <it>Dicer1 </it>in the SF1-positive cells did not affect formation and early differentiation of the adrenals and gonads. However, increasing numbers of apoptotic cells were first detected in the <it>Dicer1 </it>knockout adrenal cortex at 18.5 days post coitum (dpc), followed by apoptosis of somatic cells and germ cells in the testis at postnatal day 0. Affected adrenal and testes underwent complete degeneration 48 hrs after the onset of apoptosis. However, ovaries were not affected at least until postnatal day 5, when the animals died due to adrenal insufficiency.</p> <p>Conclusions</p> <p><it>Dicer1 </it>is dispensable for formation and differentiation of fetal tissues derived from the SF1-positive adrenogonadal primordium. <it>Dicer1 </it>is essential for maintaining cell survival in adrenal and testis; however, development of the ovary from fetal stages to postnatal day 5 does not require the presence of <it>Dicer1</it>. Our results reveal a tissue-specific requirement of <it>Dicer1 </it>and microRNAs. Future research is needed to understand how the tissue-specific role of <it>Dicer1 </it>is established.</p>
|
|---|
