Combinatorial regulation of gene expression by uORFs and microRNAs in Drosophila

Gene expression is tightly controlled at multiple levels by different categories of cis-regulatory elements (CREs) and trans-acting factors (TAFs). Two different regulators might have additive or even synergistic effects, enabling robust repression or activation of target gene expression (i.e., the “fail-safe” regulation). Alternatively, two regulators might antagonistically regulate the same targets, which seems futile, but could stabilize gene expression. As a transcript could be regulated by multiple mechanisms, the combinatorial use of different categories of CREs and TAFs might be prevalent in modulating the function and fate of an mRNA.