Project description:The microRNAs known as miR-34 family suppress the expression of a suit of proteins involved in oncogenesis and pluripotency, including c-Myc. Their expression is frequently down regulated in cancers; however the regulation of their expression is not well understood. Through genome-wide miRNA profiling and mechanistic analysis, we identified an important role of SUMOylation in miR-34b/c expression, regulating the expression of c-Myc and all other tested miR-34 targets.
Project description:The microRNAs known as miR-34 family suppress the expression of a suit of proteins involved in oncogenesis and pluripotency, including c-Myc. Their expression is frequently down regulated in cancers; however the regulation of their expression is not well understood. Through genome-wide miRNA profiling and mechanistic analysis, we identified an important role of SUMOylation in miR-34b/c expression, regulating the expression of c-Myc and all other tested miR-34 targets.
Project description:The aim of this small RNA Seq is to determine if the sequence reads observed for hsa-miR-34b-5p and hsa-miR-449c-5p represent library artifacts or sequencing artifacts
Project description:The miR-34 family of microRNAs consisting of miR-34a, miR-34b and miR-34c are tumour suppressors. The annotated human miR-34b-5p has one additional base at the 5’ end of the common miR-34 family seed sequence, compared to miR-34a-5p and miR-34c-5p. This extra base results in a shift of the seed sequence, which would affect the target gene repertoire and have functional consequences. During our studies of miR-34 functions, we investigated the precise sequence of mature miR-34b-5p in human cells by deep sequencing. We found that a miR-34b-5p without the extra base was the predominant form in both non-malignant and malignant cells derived from several human tissues, indicating that the miR-34b annotation is misleading. We evaluated the functional implications of the seed shift, by comparing the effect of mimics representing the alternative miR-34b-5p sequences in MDA-MB-231 cells. In contrast to the annotated miR-34b, the endogenously expressed miR-34b displayed tumour suppressive characteristics in vitro similarly to miR-34c. These data demonstrate the importance of determining the precise sequence of a mature microRNA before exploring miRNA functions.
