MicroRNA-142 controls thymocyte proliferation.

T-cell development is a spatially and temporally regulated process, orchestrated by well-defined contributions of transcription factors and cytokines. Here, we identify the noncoding RNA miR-142 as an additional regulatory layer within murine thymocyte development and proliferation. MiR-142 deficiency impairs the expression of cell cycle-promoting genes in mature mouse thymocytes and early progenitors, accompanied with increased levels of cyclin-dependent kinase inhibitor 1B (Cdkn1b, also known as p27 ).