Elucidation of the differential gene expression during differentiation of HSC and progenitors could have far reaching implications for ex vivo manipulation of HSC, clinical BM transplantation and gene therapy of hématologie disorders. Using (a) differential screening and subtraction of full-length cDNA libraries prepared from purified mouse Lin Sea-1 (containing HSC) and LurSca-l' (lacking HSC) bone marrow cells, and (b) cDNA clone arraying and expression screening, we have identified a number of novel candidate genes. Here we report cloning and characterization of two novel genes with differential expression in HSC and progenitors. LS215 is a novel highly conserved gene in mouse and humans, that encodes a 267 aa protein of unknown function and with no visible domains. It is expressed in mouse embryo, brain, lymph node, thymus, and spleen. During embryonic blood cell development LS215 is not expressed in mouse fetal liver HSC (Sca-lcfAA4.1 Lin cells), but is highly expressed in progenitor cell population (AA4.1 'cells). During adult hematopoiesis, LS215 is expressed at low to moderate level in bone marrow HSC (Rh-123Sca-c-faLin- and Lin'Sca-T) and progenitor cell populations (Lin'Sca1 ), with upregulated expression throughout lymphoid cell development and downregulated expression in myeloid cell types. LS372 is a novel highly conserved ring finger gene present in Drosophila, zebrafish, Xenopus, mouse and humans. It is expressed in mouse embryo, brain, kidney, muscle and thymus. During embryonic hematopoiesis LS372 is abundantly transcribed in mouse fetal liver HSC (Sca-re-farAA4.1Lin cells), but is not expressed in progenitor cells (AA4.1 ). In adult mice expression of LS372 is upregulated as mouse bone marrow HSC (LinSca-1+ and Rh-123lowSca-rc-ttLin+) differentiate into progenitors (LinSca-1-) and lymphoid and myeloid cell types. The fact that LS215 and LS372 both show differential expression in mouse fetal and adult HSC and progenitors suggests that these genes may play an important role in HSC/progenitor cell lineage commitment and differentiation. The expression of human LS215 and LS372 genes in human HSC and progenitors is being analyzed. Using ES cell clones in which alleles for LS215 and LS372 genes were inactivated by splice acceptor gene trap vector pGT1.8TMβgeo (Dr. Skarnes, UC Berkeley), we are generating knockout mice to study their role in blood cell development and differentiation.
|Original language||English (US)|
|Issue number||11 PART I|
|State||Published - Dec 1 2000|
ASJC Scopus subject areas
- Cell Biology