title: Inactivation of a single copy of Crebbp selectively alters pre-mRNA processing in mouse hematopoietic stem cells.
abstract: Global expression analysis of fetal liver hematopoietic stem cells (FL HSCs) revealed the presence of unspliced pre-mRNA for a number of genes in normal FL HSCs. In a subset of these genes, Crebbp+/- FL HSCs had less unprocessed pre-mRNA without a corresponding reduction in total mRNA levels. Among the genes thus identified were the key regulators of HSC function Itga4, Msi2 and Tcf4. A similar but much weaker effect was apparent in Ep300+/- FL HSCs, indicating that, in this context as in others, the two paralogs are not interchangeable. As a group, the down-regulated intronic probe sets could discriminate adult HSCs from more mature cell types, suggesting that the underlying mechanism is regulated with differentiation stage and is active in both fetal and adult hematopoiesis. Consistent with increased myelopoiesis in Crebbp hemizygous mice, targeted reduction of CREBBP abundance by shRNA in the multipotent EML cell line triggered spontaneous myeloid differentiation in the absence of the normally required inductive signals. In addition, differences in protein levels between phenotypically distinct EML subpopulations were better predicted by taking into account not only the total mRNA signal but also the amount of unspliced message present. CREBBP thus appears to selectively influence the timing and degree of pre-mRNA processing of genes essential for HSC regulation and thereby has the potential to alter subsequent cell fate decisions in HSCs.
authors: Department of Pediatric Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts, United States of America.
authors: Madeleine E
authors: ME
authors: Lemieux
authors: Ziming
authors: Z
authors: Cheng
authors: Qing
authors: Q
authors: Zhou
authors: Ruth
authors: R
authors: White
authors: John
authors: J
authors: Cornell
authors: Andrew L
authors: AL
authors: Kung
authors: Vivienne I
authors: VI
authors: Rebel
mesh_terms: D000818:Animals; D015153:Blotting, Western; D050882:CREB-Binding Protein / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D005260:Female; D006412:Hematopoietic Stem Cells / Q000378:metabolism*; D008297:Male; D051379:Mice; D020411:Oligonucleotide Array Sequence Analysis; D012322:RNA Precursors / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D012322:RNA Precursors; D034741:RNA, Small Interfering; D050882:CREB-Binding Protein; C494364:Crebbp protein, mouse