ZNF451 is a Novel Binding Partner of the bHLH Transcription Factor E12
Abstract (Summary)E12 is a member of the class I basic helix-loop-helix (bHLH) proteins, which contains a basic DNA binding domain and a helix-loop-helix (HLH) protein interaction domain. E12 is a multifunctional transcription factor that is involved in a large variety of developmental processes. It plays an important role in embryonic patterning, cell fate determination, cell differentiation and proliferation. In human prostate cancer cells, E12 interacts with Id1 (DNA binding inhibitor 1), a dominant negative member of the HLH family of transcriptional regulators. This complex may alter transcriptional activity, promote malignancy and facilitate transition to androgen independence. Using the bHLH domain of E12 as bait in a yeast two hybrid screen of an LNCaP prostate cancer cell cDNA library, we identified an interaction between E12 and Zinc Finger Protein 451(ZNF451) and the interaction of E12 and ZNF451 is further verified by coimmunoprecipitation. While the DNA-binding properties of some zinc finger proteins have been explored in detail, the function of ZNF451 is currently unknown. Real time PCR detection showed expression of ZNF451 transcript in multiple human cancer cell lines, including HepG2 (human hepatocellular carcinoma cells) and MEG-01(human megakaryoblast cells). Furthermore, we found increased ZNF451 transcript level in LNCaP androgen independent prostate cancer sublines compared to parental androgen dependent LNCaP cells. Also, from the quantitative PCR analysis, ZNF451 transcript level shows testis specific in mouse tissues compared to that in human tissues. ZNF451 is comprised of 1,061 amino acids, and contains 11 C2H2-type zinc fingers and an ubiquitin interaction motif at C terminal. Immunostaining demonstrated that ZNF451 is localized to nucleus as tiny speckles. Upon co-expression with E12, ZNF451 accumulated and colocalized with E12 in nuclear and also supporting the interaction of E12 with ZNF451. These results demonstrate for the first time the interaction of E12 with ZNF451 and indicate a possible novel mechanism by which E12 is linked to the development of disease including cancer.
School Location:USA - Ohio
Source Type:Master's Thesis
Keywords:bhlh transcription factor zinc finger
Date of Publication:01/01/2008