Transcription of the chicken myb proto-oncogene starts within a CpG island.
The nucleotide sequence of an 8.2-kb DNA fragment from the 5' proximal part of the chicken myb proto-oncogene spanning 1761 nucleotides upstream and 6436 nucleotides downstream from a presumed c-myb initiation codon was determined. A 3.3-kb G + C-rich region found in this sequence had also other features characterizing CpG islands, i.e. no CpG underrepresentation and lack of CpG methylation. In haematopoietic tissues c-myb mRNA synthesis starts in two major regions of the CpG island, namely 98 to 108 and 143 to 145 nucleotides upstream from the c-myb initiation codon. These two regions are in or close to the 124-bp evolutionarily conserved element located in the middle part of the CpG island. No alternative splicing of the 5' end of c-myb mRNA suggested earlier (1,2) was observed. The c-myb promoter contains neither TATA nor CAAT box-like structures at the usual positions. Instead, numerous potential Sp1 factor binding sites were found both upstream and downstream from the transcription initiation sites. Moreover, consensus v-myb protein DNA-binding sites were revealed in the promoter region and in sequences downstream from it.
Dvorák
M
M
Institute of Molecular Genetics, Czechoslovak Academy of Sciences, Prague.
Urbánek
P
P
Bartůnĕk
P
P
Paces
V
V
Vlach
J
J
Pecenka
V
V
Arnold
L
L
Trávnicek
M
M
Ríman
J
J
D000818:Animals; D001483:Base Sequence; D002645:Chickens; D003001:Cloning, Molecular; D015226:Dinucleoside Phosphates / Q000032:analysis*; D004720:Endonucleases; D004912:Erythrocytes / Q000032:analysis; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D009928:Organ Specificity; D011401:Promoter Regions, Genetic; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D020598:Proto-Oncogene Proteins c-myb; D011519:Proto-Oncogenes; D012315:RNA Caps / Q000235:genetics; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D015719:Single-Strand Specific DNA and RNA Endonucleases; D013950:Thymus Gland / Q000032:analysis; D014158:Transcription, Genetic
D015226:Dinucleoside Phosphates; D004720:Endonucleases; D011518:Proto-Oncogene Proteins; D020598:Proto-Oncogene Proteins c-myb; D012315:RNA Caps; D015719:Single-Strand Specific DNA and RNA Endonucleases; C015772:CpG dinucleotide