Specific binding of heterogeneous ribonucleoprotein particle protein K to the human c-myc promoter, in vitro.
1993; Elsevier BV; Volume: 268; Issue: 24 Linguagem: Inglês
10.1016/s0021-9258(17)46837-2
ISSN1083-351X
AutoresMasato Takimoto, Takeshi Tomonaga, Michael J. Matunis, Mark Avigan, Henry C. Krutzsch, Gideon Dreyfuss, David Levens,
Tópico(s)Ubiquitin and proteasome pathways
ResumoIA homopurine/homopyrimidine-like sequence is found 100-150 base pairs upstream of the human c- myc promoter P1.This element, termed the CT-element, has been shown to augment expression from P1, and it serves as a positive transcriptional element when coupled to a heterologous promoter in vivo and in vitro.Synthetic oligonucleotides comprising this element were used to form DNA-protein complexes in electrophoretic mobility shift assays.By using conventional and affinity methods, 61-and 34-kDa proteins were shown to be associated with these complexes.Amino acid sequence analysis and immunological methods have identified these proteins as heterogeneous ribonucleoprotein particle (hnRNP) proteins K and A l .Surprisingly, hnRNP protein K binds to the pyrimidine-rich strand of the CT-element in a sequence-specific manner as well as to the double-stranded molecule.Cotransfection of vectors encoding hnRNP protein K in the sense or anti-sense orientations with reporter plasmids driven by wild-type or mutant CTelements demonstrates that hnRNP protein K augments gene expression in a cis-element-dependent manner.Taken together, these results suggest that hnRNP protein K may play a role in the transcriptional regulation of the human c-myc gene.The c-myc protooncogene product encodes a sequence-specific DNA-binding protein that plays a central role in the regulation of cell growth and differentiation (Blackwell et al.,
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