title: The chicken A-myb protein is a transcriptional activator.
abstract: c-myb encodes a trans-activator that is essential for the proliferation of most hematopoietic precursor cells but lacks a major role in non-hematopoietic cells. The recent identification of two myb-related genes (A-myb and B-myb) in several vertebrate species has raised the possibility that these genes perform c-myb like functions in non-hematopoietic cells. Here, we report the isolation and preliminary characterization of the chicken A-myb gene. Like other members of the myb family, the A-myb protein contains an N-terminally located repeat domain that is highly homologous to the DNA-binding domain of the c-myb protein. Unlike c-myb, A-myb is expressed in fibroblasts, suggesting that it functions in non-hematopoietic cells. We demonstrate that A-myb transactivates myb-responsive reporter genes. Furthermore, when stably expressed in a chicken macrophage cell line. A-myb causes activation of several myb-inducible endogenous genes. These findings show that A-myb encodes a transactivating member of the myb family whose functional properties resemble those of the c-myb and v-myb proteins. Thus, our results support the idea that A-myb is a functional equivalent of c-myb.
authors.affiliation: Hans-Spemann-Laboratory, Max-Planck-Institute for Immunobiology, Freiburg, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Foos
authors.forename: S
authors.initials: S
authors.lastname: Grimm
authors.forename: K H
authors.initials: KH
authors.lastname: Klempnauer
mesh_terms: D000123:Acetyltransferases; D000595:Amino Acid Sequence; D000818:Animals; D030161:Avian Proteins; D001483:Base Sequence; D002460:Cell Line; D002645:Chickens; D008969:Molecular Sequence Data; D009113:Muramidase / Q000235:genetics; D009857:Oncogenes; D010641:Phenotype; D011506:Proteins / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology*; D020598:Proto-Oncogene Proteins c-myb; D015534:Trans-Activators / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology*
chemical_list: C490284:A-MYB protein, chicken; D030161:Avian Proteins; D011506:Proteins; D011518:Proto-Oncogene Proteins; D020598:Proto-Oncogene Proteins c-myb; D015534:Trans-Activators; D000123:Acetyltransferases; C077509:mim-1 protein, Gallus gallus; D009113:Muramidase