BioProject

performed a genetic screen for microRNAs that are differentially expressed between LSK, LS−K+, erythroid and myeloid cells isolated from C57BL/6 and DBA/2 mice. More...

performed a genetic screen for microRNAs that are differentially expressed between LSK, LS−K+, erythroid and myeloid cells isolated from C57BL/6 and DBA/2 mice. This analysis identified 131 microRNAs that were differentially expressed between cell types and 15 that were differentially expressed between mouse strains. Of special interest was an evolutionary conserved miR-cluster located on chromosome 17 consisting of miR-99b, let-7e and miR-125a. All cluster members were most highly expressed in LSKs and down-regulated upon differentiation. In addition, these microRNAs were higher expressed in DBA/2 cells compared to C57BL/6 cells, and thus correlated with HSPC frequency. To functionally characterize these microRNAs, we overexpressed the entire miR-cluster 99b/let-7e/125a and miR-125a alone in BM cells from C57BL/6 mice. Overexpression of the miR-cluster or miR-125a dramatically increased day-35 CAFC activity and caused severe hematopoietic phenotypes upon transplantation. We showed that a single member of the miR-cluster, namely miR-125a, is responsible for the majority of the observed miR-cluster overexpression effects. Finally, we performed genome-wide gene expression arrays and identified candidate target genes through which miR-125a may modulate HSPC fate. Overall design: Microarray-based microRNA profiling study was peformed of four developmentally related hematopoietic cell types isolated from the BM of B6 and D2 mice. Total RNA isolated from purified LSK multilineage cells, committed LS−K+ cells, erythroid TER-119+ cells and myeloid Gr-1+ cells was hybridized to Agilent microRNA arrays. Triplicates were generated for each of the 8 conditions (4 cell types, 2 mouse strains). From the final anaysis one replicate for B6 LS-K+ cells was removed based on PCA, therefore B6 Prog group consist of only 2 biological replicates. Less...