title: Targeted disruption of c-myb in the chicken pre B-cell line DT40.
abstract: The c-myb proto-oncogene is highly expressed in a wide variety of immature hematopoietic cells and plays a key role in the development of the hematopoietic system. c-myb and its retroviral counterpart v-myb encode transcription factors which have been implicated in the regulation of certain target genes. Targeting of c-myb in mouse embryonic stem cells by homologous recombination has provided clear evidence that c-myb is necessary for the proper development of most myeloid lineages of the hematopoietic system as well as of T-lymphocytes. Here we have explored the function of c-myb in the B-lymphoid lineage. We have used the chicken DT40 cells, a pre B-cell line which shows extremely high efficiencies of homologous recombination, as a model system to disrupt c-myb. DT40 cells lacking a functional c-myb gene are viable and show only minor perturbations of their growth parameters, indicating that c-myb is not an essential gene in these cells. We have used the c-myb null DT40 cells to analyse the expression of genes which have been previously been identified as myb target genes. Neither c-myc nor bcl-2, two putative myb targets, showed altered expression in the cells lacking c-myb. However, expression of the Pdcd4 gene, a myb target gene originally identified in a myelomonocytic cell line expressing a conditional form of v-myb, was diminished in the absence of c-myb. The c-myb knock-out cells described here should provide a useful model system for the identification and characterization of c-myb target genes in B-lymphoid cells.
authors.affiliation: Institut für Biochemie, Westfälische-Wilhelms-Universität Münster, Wilhelm-Klemm-Str. 2, D-48143 Münster, Germany.
authors.forename: Hartmut
authors.initials: H
authors.lastname: Appl
authors.forename: Karl-Heinz
authors.initials: KH
authors.lastname: Klempnauer
mesh_terms: D000818:Animals; D017209:Apoptosis; D001402:B-Lymphocytes / Q000166:cytology / Q000378:metabolism*; D002453:Cell Cycle; D002460:Cell Line; D002645:Chickens / Q000235:genetics*; D005786:Gene Expression Regulation; D018390:Gene Targeting; D020570:Genes, myb; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000378:metabolism*; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics; D020598:Proto-Oncogene Proteins c-myb / Q000172:deficiency / Q000502:physiology*; D016601:RNA-Binding Proteins
chemical_list: D011506:Proteins; D020598:Proto-Oncogene Proteins c-myb; D016601:RNA-Binding Proteins