RNA intererence is a one of the major mechanisms of post-transcriptional regulation of protein expression in eukaryotes. This mechanism is using small non-coding RNAs (miRNAs) to destabilize specific mRNAs and to suppress protein synthesis. Many miRNAs genes are expressed in T cells during development in a thymus. However the function of RNAi in T cell development remains unclear. To investigate the role of RNAi during thymic development we generated conditional knockout of the enzyme Dicer in the mouse, which is critical for miRNA generation. We observed a dramatic reduction in the number of thymocytes in Dicer-deficient mice and we determined that the reason is a block of progression from DN to DP stage during thymocyte development. Importantly, we found an alteration in the balance between pro- and anti-apoptotic factors in RNAi deficient DP thymocytes. We also observed that RNAi-deficient thymocytes are rapidly undergoing apoptosis. Most importantly, we have also identified the precise gene whose expression is downregulated by microRNAs to permit survival of developing T cells in the thymus.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Investigator-Initiated Intramural Research Projects (ZIA)
Project #
1ZIABC011114-06
Application #
8763352
Study Section
Project Start
Project End
Budget Start
Budget End
Support Year
6
Fiscal Year
2013
Total Cost
$244,735
Indirect Cost
Name
National Cancer Institute Division of Basic Sciences
Department
Type
DUNS #
City
State
Country
Zip Code
Tai, Xuguang; Singer, Alfred (2014) Basis of Treg development in the thymus. Cell Cycle 13:501-2