MicroRNA and glucocorticoid signaling
The absolute protein level of hormone receptors is a crucial determinant for cellular responsiveness towards hormone exposure. In that respect, it is important to note that, by recent progress in gene expression profiling techniques, a novel class of small non-coding RNAs has been discovered. These non-coding transcripts of approximately 21 nucleotides are called microRNAs (miRNAs) that downregulate protein levels in a cell by translational repression. Given the increasing and varied number of functions attributed to miRNAs, it is plausible to hypothesize that miRNAs regulate levels of proteins involved in glucocorticoid feedback mechanisms, in particular because miRNAs preferentially target transcription factors. In the lecture, I will highlight the role of miRNAs in endocrine signalling and present experimental evidence that protein levels of the glucocorticoid receptor are under control of cell-type specific microRNAs.