title: B-myb is required for inner cell mass formation at an early stage of development.
abstract: The myb gene family has three members, c-myb, A-myb, and B-myb, which have distinct expression patterns. Analyses of c-myb and A-myb mutant mice have indicated that c-myb and A-myb are important for hematopoiesis and spermatogenesis, respectively. However, there has been no evidence for a role for B-myb in development. To examine the role of B-myb in development, we generated B-myb-deficient mice by gene targeting. Although the heterozygous mutants were healthy, the homozygous mutants died at an early stage of development, around E4. 5-E6.5. In vitro culture of blastocyst indicated that B-myb is required for inner cell mass formation. Consistent with the important role of B-myb in early embryonic development, only B-myb among myb family members was expressed in embryonic stem cells. These results indicate that each of the three members of the myb gene family plays a distinct role during development.
authors.affiliation: Laboratory of Molecular Genetics, RIKEN Tsukuba Life Sciences Center, 3-1-1 Koyadai, Tsukuba, Ibaraki 305-0074, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Tanaka
authors.forename: N P
authors.initials: NP
authors.lastname: Patestos
authors.forename: T
authors.initials: T
authors.lastname: Maekawa
authors.forename: S
authors.initials: S
authors.lastname: Ishii
mesh_terms: D000818:Animals; D001483:Base Sequence; D001755:Blastocyst / Q000166:cytology*; D018797:Cell Cycle Proteins; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D047108:Embryonic Development; D005260:Female; D008297:Male; D051379:Mice; D008817:Mice, Mutant Strains; D011247:Pregnancy; D015534:Trans-Activators / Q000235:genetics / Q000502:physiology*
chemical_list: D018797:Cell Cycle Proteins; D017931:DNA Primers; D004268:DNA-Binding Proteins; C499306:Mybl2 protein, mouse; D015534:Trans-Activators