C-myb proto-oncogene: evidence for intermolecular recombination of coding sequences.
We have characterized a novel chicken c-myb exon whose sequences are specifically expressed in thymic cells. In situ hybridization experiments indicate that this thymus-specific coding exon is localized on a small chromosome, distinct from the large acrocentric chromosome 3 on which we recently mapped the bulk of 15 exons, common to the c-myb mRNA species expressed in hematopoietic cells of both B and T lineages. These observations indicate that intermolecular recombination is required for the tissue-specific expression of the c-myb proto-oncogene. We also show that these thymus-specific sequences are conserved in human DNA and lie on chromosome 17q25, whereas the human c-myb locus is localized on chromosome 6q22-23. Sequencing data obtained from genomic DNA and PCR analyses performed with c-myb mRNA species expressed in chicken thymic cells strongly suggest that a repeated decameric sequence plays a key role in the recombination process.
Vellard
M
M
Institut Curie, Centre Universitaire, Orsay, France.
Soret
J
J
Viegas-Pequignot
E
E
Galibert
F
F
Nguyen
V C
VC
Dutrillaux
B
B
Perbal
B
B
D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D002645:Chickens / Q000235:genetics*; D002874:Chromosome Mapping; D002886:Chromosomes, Human, Pair 17; D004330:Drosophila / Q000235:genetics; D005091:Exons; D006801:Humans; D006822:Hybrid Cells; D051379:Mice; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D020598:Proto-Oncogene Proteins c-myb; D012333:RNA, Messenger / Q000032:analysis; D011995:Recombination, Genetic; D012689:Sequence Homology, Nucleic Acid; D013950:Thymus Gland / Q000378:metabolism
C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D020598:Proto-Oncogene Proteins c-myb; D012333:RNA, Messenger