Isolation of human cDNA clones ofmyb-related genes, A-myband B-myb

Abstract

cDNA clones of the myb-related genes A-myb and B-myb were obtained by screening human cDNA libraries. The predicted open reading frame of B-myb could encode a protein of 700 amino acid residues. Although the C-terminal end has not been cloned yet, an almost entire coding region of A-myb, which is 745 amino acid long, was determined. The A-myb and B-myb proteins are highly homologous with the myb protein in three regions. Domain I, which is 161 amino acid long, is well conserved in the myb gene family. The homology between human-myb and A-myb in domain I is 90% at the amino acid level. Domain II, which is about 85 amino acid long, is less well conserved. Although it is a short stretch, domain III is found in the C-terminal region. The mRNAs of A-myb and B-myb were 5.0 and 2.6 kb, respectively. The mRNA expression pattern of the myb gene family in various tumors is presented.

Physical interaction between CDK9 and B-Myb results in suppression of B-Myb gene autoregulation

“…B-Myb is a member of the Myb family that includes cMyb and A-Myb (Nomura et al, 1988). v-myb, the prototype member of the family, is the transforming gene of the E26 and AMV viruses that cause myeloblastosis in birds, and has been described as the truncated derivative of the cellular gene c-myb (Gonda and Bishop, 1983;Klempnauer et al, 1983).…”

“…Down regulation of c-myb levels correlates with induction of terminal di erentiation of hemopoietic cells (Ho man-Liebermann and Liebermann, 1991). Unlike the other members of the family, B-Myb expression is ubiquitous and strictly correlates with cell proliferation , being highest at the G1/S border of the cell cycle (Nomura et al, 1988;Reiss et al, 1991;Watson et al, 1993). Analysis of B-Myb mRNA levels in non-dividing tissues and in the whole mouse embryo con®rms that BMyb expression is linked to DNA synthesis (Sitsmann et al, 1996;Bouwmeester et al, 1992).…”

B-Myb function can be markedly enhanced by cyclin A-dependent kinase and protein truncation

“…B-Myb is a member of a small family of genes that includes two other known members, A-Myb and c-Myb (Nomura et al, 1988). Whereas A-Myb and c-Myb are expressed in restricted tissues, expression of B-Myb is ubiquitous in proliferating somatic cells (Nomura et al, 1988;Sitzmann et al, 1996).…”

“…Whereas A-Myb and c-Myb are expressed in restricted tissues, expression of B-Myb is ubiquitous in proliferating somatic cells (Nomura et al, 1988;Sitzmann et al, 1996). The Myb proteins are localised to the cell nucleus and bind a PyAACG/TG consensus DNA sequence (Biedenkapp et al, 1988), designated the Myb binding site (MBS).…”

Myb targeted therapeutics for the treatment of human malignancies

“…Myb is a member of a family of transcription factors composed of at least two other highly homologous genes designated A-myb and B-myb (Nomura et al, 1988). Located on chromosome 6q in humans, c-myb's predominant transcript encodes a *75 kDa nuclear binding protein (Myb) which recognizes the core consensus sequence 5'-PyAAC(G/Py)G-3' (Biedenkapp et al, 1988).…”