Expression patterns of c-myb and of v-myb induced myeloid-1 (mim-1) gene during the development of the chick embryo.
The v-myb oncogene of the acute avian leukemia virus E26 encodes a transcription factor that directly regulates the promyelocyte-specific mim-1 gene (Ness, S.A., Marknell, A. and Graf, T. Cell, 59, 1115-1125). We have investigated the relationship between the c-myb proto-oncogene and the transcription of the mim-1 gene both in vitro and in vivo. We demonstrate that the c-myb protein can transactivate the transcription of mim-1 in a transient transfection assay. In the chick embryo, we confirm that mim-1 is specifically expressed during granulopoiesis and we show that the expression of c-myb and mim-1 are perfectly correlated in the granulocytic spleen and pancreas. However we suggest that mim-1 is efficiently transcribed in the absence of c-myb in the yolk sac and in the promyelocytes at the onset of the colonization of the bursa of Fabricius. On the other hand c-myb transcripts detected in the early hemopoietic progenitor cells, in lymphoid cells and in proliferative epithelia are never associated with mim-1 transcription. We conclude that the granulocyte-specific mim-1 gene is regulated by c-myb-dependent and c-myb-independent mechanisms depending upon the environment in which granulocytic precursor cells differentiate.
Quéva
C
C
INSERM U186/CNRS URA1160, Institut Pasteur, Lille, France.
Ness
S A
SA
Grässer
F A
FA
Graf
T
T
Vandenbunder
B
B
Stéhelin
D
D
D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D002642:Chick Embryo; D005796:Genes / Q000235:genetics*; D006098:Granulocytes / Q000502:physiology; D006133:Growth Substances / Q000235:genetics*; D006410:Hematopoiesis / Q000235:genetics*; D009132:Muscles / Q000196:embryology; D020626:Oncogene Proteins v-myb; D010179:Pancreas / Q000196:embryology / Q000502:physiology; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D020598:Proto-Oncogene Proteins c-myb; D015682:Retroviridae Proteins, Oncogenic / Q000235:genetics*; D013154:Spleen / Q000196:embryology / Q000502:physiology; D013950:Thymus Gland / Q000196:embryology / Q000502:physiology; D014158:Transcription, Genetic / Q000235:genetics*; D015533:Transcriptional Activation / Q000235:genetics*; D015017:Yolk Sac / Q000502:physiology
D006133:Growth Substances; D020626:Oncogene Proteins v-myb; D011518:Proto-Oncogene Proteins; D020598:Proto-Oncogene Proteins c-myb; D015682:Retroviridae Proteins, Oncogenic