title: Def-2, -3, -6 and -8, novel mouse genes differentially expressed in the haemopoietic system.
abstract: To identify developmentally regulated genes during myeloid differentiation, a self-inactivating retroviral gene-trap vector carrying a beta-galactosidase-neomycin (SA/lacZ/neo) fusion gene was constructed and used to infect myeloid progenitor cells (FDCP-Mix A4). G418-resistant and beta-galactosidase positive cell lines (gene-trap integration [GTI] clones) were established and induced to differentiate in vitro into either macrophages or granulocytes. Expression of the trapped loci was monitored at a single-cell level by analysing the mature cell types for beta-galactosidase activity. All 37 GTI clones tested showed down-regulation either during granulocyte or both granulocytic and macrophage differentiation. The endogenous coding regions fused to the SA/lacZ/neo reporter gene were isolated from eight clones. Molecular analysis revealed that half of them represented novel mouse genes (def-2, -3, -6 and -8) which we confirmed to be differentially expressed in primary haemopoietic tissues. Database searches revealed no significant similarities for def-2 (associated with haemopoietic progenitors) and def-8 (expressed most strongly in peripheral leucocytes). Def-6, which is down-regulated upon the differentiation into myeloid as well as erythroid lineages, was found to be closely related but not identical with the recently described B-cell-specific switch recombinase SWAP-70. Def-3, which is down-regulated upon differentiation into granulocytes but expressed in progenitor cells and macrophages, defines a novel family of RNA binding proteins.
authors.affiliation: Max-Delbrück-Laboratory in the MPG, Cologne, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Hotfilder
authors.forename: S
authors.initials: S
authors.lastname: Baxendale
authors.forename: M A
authors.initials: MA
authors.lastname: Cross
authors.forename: F
authors.initials: F
authors.lastname: Sablitzky
mesh_terms: D000818:Animals; D005786:Gene Expression Regulation; D005822:Genetic Vectors; D006410:Hematopoiesis / Q000235:genetics*; D006413:Hematopoietic System / Q000166:cytology / Q000378:metabolism; D051379:Mice; D013234:Stem Cells / Q000166:cytology / Q000201:enzymology; D016662:Virus Integration; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D001616:beta-Galactosidase