Biochemical and Biophysical Research Communications
Transcription of dbpA, a Y box binding protein, is positively regulated by E2F1: implications in hepatocarcinogenesis
Section snippets
Materials and methods
Plasmid construction. The firefly luciferase expression vector was made by insertion of the synthesized DNA corresponding to the dbpA promoter region into pGL3-Basic vector (Promega). The DNAs were synthesized so that they contained the MluI and BglII recognition site at each end after annealing. They were digested with MluI and BglII, and ligated to the MluI–BglII digested pGL3-Basic vector. The synthetic DNAs covering −17 to +106 relative to the transcription start point (123 mer), −4 to +106
Decreased transcriptional activity of dbpA promoter region without the sequences resembling E2F binding site
As shown in Fig. 1, the sequence 5′-TTTGGGGC-3′ (−8 to −1) resembling the E2F binding element 5′-TTT(G/C)GCGC-3′ exists in the dbpA promoter region. In order to examine whether this sequence is important for the transcriptional activity of this promoter, we prepared reporter vectors containing this region with successive deletions, shown in Fig. 2A, and assayed their luciferase activity. Luciferase activity was highest with the vector containing the (−17 to +106) region, in which the 8-base
Discussion
The frequency of human HCC is dependent on the severity and duration of chronic inflammation of the liver, regardless of its etiology. We previously reported that dbpA, a member of the Y box binding protein family, could accelerate inflammation-induced hepatocarcinogenesis [8]. The finding of enhanced expression of dbpA in human HCC [8] and in regenerating mouse liver (Fig. 4) suggested that dbpA is a proliferation-associated protein, like YB-1, the prototype member of the same family [3], [4],
References (34)
- et al.
Gene regulation by Y-box proteins: coupling control of transcription and translation
Trends Cell. Biol.
(1998) - et al.
Single-step method of RNA isolation by acid guanidinium thiocyanate–phenol–chloroform extraction
Anal. Biochem.
(1987) - et al.
Cell cycle deregulation in liver lesions of rats with and without genetic predisposition to hepatocarcinogenesis
Hepatology
(2002) - et al.
TFDP1, CUL4A, and CDC16 identified as targets for amplification at 13q34 in hepatocellular carcinomas
Hepatology
(2002) - et al.
Emerging roles for E2F: beyond the G1/S transition and DNA replication
Cancer Cell
(2003) - et al.
Key roles for E2F1 in signaling p53-dependent apoptosis and in cell division within developing tumors
Mol. Cell
(1998) - et al.
Two human genes isolated by a novel method encode DNA-binding proteins containing a common region of homology
Gene
(1988) Structural and functional properties of the evolutionarily ancient Y-box family of nucleic acid binding proteins
Bioessays
(1994)- et al.
Nuclear localization and increased levels of transcription factor YB-1 in primary human breast cancers are associated with intrinsic MDR1 gene expression
Nat. Med.
(1997) - et al.
Nuclear expression of the Y-box binding protein, YB-1, as a novel marker of disease progression in non-small cell lung cancer
Clin. Cancer Res.
(2001)