Identification and characterization of the Myb-inducible promoter of the chicken adenosine receptor 2B gene.
Numerous studies have shown that the retroviral oncogene v-myb encodes a transcription factor (v-Myb) which interferes with the differentiation program of myelomonocytic cells. It is generally thought that v-Myb deregulates the expression of specific target genes and thereby causes transformation of these cells. By using an estrogen-inducible version of v-Myb we have previously identified the gene for the chicken A2B adenosine receptor (A2B-AR), a member of the seven-pass transmembrane receptor superfamily, as a bona fide target gene for v-Myb. The chicken A2B-AR gene is expressed in v-myb transformed myeloblasts as well as in c-myb expressing erythroblasts, offering the opportunity to study how Myb transcription factors activate a target gene in two different hematopoietic lineages. Here, we report the characterization of the promoter of the A2B-AR gene. We show that the A2B-AR promoter region contains an exceptionally large number of Myb binding sites, many of which contribute to the Myb-inducibility of the promoter. The same sites were required for promoter activity in myelomonocytic and erythroid cells. In contrast to the promoters of other Myb target genes the A2B-AR promoter was not activated synergistically by Myb and other lineage-specific transcription factors that have been identified as Myb cooperation partners before. Taken together, our data suggest that the activation of the A2B-AR promoter by Myb depends on the simultaneous binding of a large number of Myb molecules.
Kattmann
Dana
D
Institut für Biochemie, Westfälische-Wilhelms-Universität Münster, Wilhelm-Klemm-Str. 2, D-48149 Münster, Germany.
Klempnauer
Karl-Heinz
KH
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D022762:CCAAT-Enhancer-Binding Proteins / Q000378:metabolism; D002460:Cell Line; D002645:Chickens / Q000235:genetics*; D003001:Cloning, Molecular; D003370:Coturnix; D004247:DNA / Q000235:genetics / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D004912:Erythrocytes / Q000378:metabolism; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D020626:Oncogene Proteins v-myb / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018047:Receptors, Purinergic P1 / Q000235:genetics*; D020218:Response Elements / Q000235:genetics; D024363:Transcription Initiation Site; D015533:Transcriptional Activation
D022762:CCAAT-Enhancer-Binding Proteins; D020626:Oncogene Proteins v-myb; D012333:RNA, Messenger; D018047:Receptors, Purinergic P1; D004247:DNA