title: Arrest of spermatogenesis and defective breast development in mice lacking A-myb.
abstract: The Myb gene family currently consists of three members, named A-, B- and c-myb. These genes encode nuclear proteins that bind DNA in a sequence-specific manner and function as regulators of transcription. In adult male mice, A-myb is expressed predominantly in male germ cells. In female mice, A-myb is expressed in breast ductal epithelium, mainly during pregnancy-induced ductal branching and alveolar development. We report here that mice homozygous for a germline mutation in A-myb develop to term but show defects in growth after birth and male infertility due to a block in spermatogenesis. Morphological examination of the testes of A-myb-/- males revealed that the germ cells enter meiotic prophase and arrest at pachytene. In adult homozygous null A-myb female mice, the breast epithelial compartment showed underdevelopment of breast tissue following pregnancy and the female mice were unable to nurse their newborn pups. These results demonstrate that A-myb plays a critical role in spermatogenesis and mammary gland development.
authors.affiliation: Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA.
authors.forename: A
authors.initials: A
authors.lastname: Toscani
authors.forename: R V
authors.initials: RV
authors.lastname: Mettus
authors.forename: R
authors.initials: R
authors.lastname: Coupland
authors.forename: H
authors.initials: H
authors.lastname: Simpkins
authors.forename: J
authors.initials: J
authors.lastname: Litvin
authors.forename: J
authors.initials: J
authors.lastname: Orth
authors.forename: K S
authors.initials: KS
authors.lastname: Hatton
authors.forename: E P
authors.initials: EP
authors.lastname: Reddy
mesh_terms: D000818:Animals; D005260:Female; D015870:Gene Expression; D018390:Gene Targeting; D018095:Germ-Line Mutation; D007248:Infertility, Male / Q000235:genetics; D008297:Male; D008321:Mammary Glands, Animal / Q000033:anatomy & histology / Q000196:embryology / Q000254:growth & development / Q000502:physiology*; D008540:Meiosis; D051379:Mice; D008969:Molecular Sequence Data; D011247:Pregnancy; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000502:physiology*; D020598:Proto-Oncogene Proteins c-myb; D013091:Spermatogenesis / Q000235:genetics / Q000502:physiology*; D013234:Stem Cells; D013737:Testis / Q000033:anatomy & histology / Q000196:embryology / Q000254:growth & development / Q000502:physiology*; D015534:Trans-Activators / Q000235:genetics / Q000502:physiology*
chemical_list: C490283:Mybl1 protein, mouse; D011518:Proto-Oncogene Proteins; D020598:Proto-Oncogene Proteins c-myb; D015534:Trans-Activators