Interaction Studies Between Truncated Hpv16/18 E7 Oncoprotein With Ctcf/Yb-1 Transcription Factors Complex
Loading...
Date
2016-05
Authors
A. Wahab, Fatin Athirah
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Human Papillomavirus (HPV) is the aetiology agent of cervical cancer where HPV16 and HPV18 are the high-risk group of HPV. Previous study had revealed the interaction between HPV16/18 E7 oncoprotein with CTCF/Yb-1 transcription factors complex. This interaction resulted in marked enhancement of c-myc expression that leads cell proliferation. By truncating HPV16 E7 and HPV18 E7 into smaller size, the exact location of interaction towards CTCF/Yb-1 can be known. This will clearly characterise the interaction biochemically and provide a better insight of the interaction. Series of truncated HPV16 E7 and HPV18 E7 had been produced by polymerase chain reaction (PCR) based on hydrophobicity analysis. The truncated HPV E7 products, CTCF-Zn domain and Yb-1 cold shock domain (CSD) had been cloned into pET16bSH3 vector and expressed in E. coli BL21 (DE3). The protein-protein interaction between truncated HPV16/18 E7 and CTCF/Yb-1complex had been analysed via Pull-down Assay. HPV16 E7 and HPV18 E7 full length had been used as control. The series of truncated HPV16 E7 and HPV18 E7 proteins were successfully expressed and purified. Pull-down assay displayed interaction between CTCF/Yb-1 and HPV16/18 E7 full length. However, the truncated domains of HPV16 E7 and HPV18 E7 did not form any binding with neither CTCF-Zn nor Yb-1 CSD. Firstly, the inability of truncated domain to interact with other protein might be due to false folding of the dimer protein. Mutation to a wild type protein might
remove the hydrophobic interaction and cause proteolytic degradation. Thus, the native structure becomes less stable. Secondly, it might be due to structure of E7 dimer protein. Truncation that lack of CR1/CR2 domain or C-terminal domain will abolishes zinc binding. In the absence of zinc, E7 cannot form dimer thus disrupting interaction with potential protein partner. Therefore, we concluded that HPV16 E7 and HPV18 E7 cannot be truncated based on hydrophobicity profile only due to protein folding and stability. The truncation of HPV16 E7 and HPV18 E7 that lack of N- or C-terminal might reduce the stability of the native protein thus disrupt the protein-protein interaction.
Description
Keywords
The interaction between HPV16/18 E7 oncoprotein , with CTCF/Yb-1 transcription factors complex.