TY - JOUR
T1 - Association of Purα and E2F-1 suppresses transcriptional activity of E2F-1
AU - Darbinian, Nune
AU - Gallia, Gary L.
AU - Kundu, Mondira
AU - Shcherbik, Natalia
AU - Tretiakova, Anna
AU - Giordano, Antonio
AU - Khalili, Kamel
N1 - Funding Information:
We wish to thank all past and present members of the Center for NeuroVirology and NeuroOncology for sharing of ideas and reagents. We also thank Cynthia Schriver for editorial assistance. This work was made possible by grants awarded by NIH to K Khalili.
PY - 1999/11/4
Y1 - 1999/11/4
N2 - Protein-protein interaction can play an important role in the control of several biological events including gene transcription, replication and cell proliferation. E2F-1 is a DNA-binding transcription factor which, upon interaction with its target DNA sequence, induces expression of several S phase specific genes allowing progression of the cell cycle. Evidently, the activity of this protein is modulated by its cellular partner, pRb, which in the hypophosphorylated form, binds to E2F-1 and inactivates its transcriptional ability. In this study, we have demonstrated that expression of a sequence-specific single-stranded DNA binding protein, Purα, in cells decreases the ability of E2F-1 to exert its transcriptional activity upon the responsive promoter derived from DHFR. Results from band shift experiments revealed that while Purα does not recognize the double-stranded DNA fragment containing the E2F-1 binding site, it has the ability to inhibit E2F-1 interaction with its target DNA sequence. Results from GST pull-down assays and the combined immunoprecipitation/Western blot analysis of nuclear extracts revealed a direct association of E2F-1 with Purα in the absence of the DNA molecule containing the E2F-1 binding site. The association of Purα with E2F-1 may increase the stability of E2F-1, as a higher level of E2F-1 was detected in cells coexpressing Purα and E2F-1. The importance of these observations with respect to the role of Purα in the control of cell cycle progression is discussed.
AB - Protein-protein interaction can play an important role in the control of several biological events including gene transcription, replication and cell proliferation. E2F-1 is a DNA-binding transcription factor which, upon interaction with its target DNA sequence, induces expression of several S phase specific genes allowing progression of the cell cycle. Evidently, the activity of this protein is modulated by its cellular partner, pRb, which in the hypophosphorylated form, binds to E2F-1 and inactivates its transcriptional ability. In this study, we have demonstrated that expression of a sequence-specific single-stranded DNA binding protein, Purα, in cells decreases the ability of E2F-1 to exert its transcriptional activity upon the responsive promoter derived from DHFR. Results from band shift experiments revealed that while Purα does not recognize the double-stranded DNA fragment containing the E2F-1 binding site, it has the ability to inhibit E2F-1 interaction with its target DNA sequence. Results from GST pull-down assays and the combined immunoprecipitation/Western blot analysis of nuclear extracts revealed a direct association of E2F-1 with Purα in the absence of the DNA molecule containing the E2F-1 binding site. The association of Purα with E2F-1 may increase the stability of E2F-1, as a higher level of E2F-1 was detected in cells coexpressing Purα and E2F-1. The importance of these observations with respect to the role of Purα in the control of cell cycle progression is discussed.
KW - E2F-1
KW - Protein-protein interaction
KW - Purα
KW - Single-stranded DNA binding protein
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U2 - 10.1038/sj.onc.1203011
DO - 10.1038/sj.onc.1203011
M3 - Article
C2 - 10597240
AN - SCOPUS:0033523883
SN - 0950-9232
VL - 18
SP - 6398
EP - 6402
JO - Oncogene
JF - Oncogene
IS - 46
ER -