ABSTRACT
A novel protein MGC5306 has been identified in yeast-two-hybrid analysis by screening a HeLa cDNA library with a truncated DNA polymerasebeta (polbetaDelta) as bait. The polbetaDelta is expressed in various types of cancers. Co-immunoprecipitation-Western blot analysis confirms not only its interaction with polbetaDelta but also with wild-type polbeta. Binding to polbeta indicates potential function of MGC5306 in repair pathway. Transfection of cells with MGC5306-GFP and Western blot analysis with anti-MGC5306 antibody reveal its nuclear localization. MGC5306 is expressed in human carcinomas and tumor cell lines but not in normal tissues, suggesting MGC5306 is most likely involved in carcinogenesis. An antigrowth activity and modulations of cell cycle events are identified in cells expressing siRNAMGC5306.
Subject(s)
DNA Polymerase beta/metabolism , Nuclear Proteins/metabolism , Amino Acid Sequence , Base Sequence , Cell Cycle , Cell Survival , Female , HeLa Cells , Humans , Molecular Sequence Data , Ovarian Neoplasms/chemistry , Phenotype , RNA, Small Interfering/pharmacology , Two-Hybrid System TechniquesABSTRACT
Dysregulation of the human transforming acidic coiled coil (TACC) genes is thought to be important in the development of multiple myeloma, breast and gastric cancer. However, even though these proteins have been implicated in the control of cell growth and differentiation, the mechanism by which they function still remains to be clarified. Using the yeast two-hybrid assay, we have now identified the histone acetyltransferase (HAT) hGCN5L2 as a TACC2-binding protein. GST pull-down analysis subsequently confirmed that all human TACC family members can bind in vitro to hGCN5L2. The authenticity of these interactions was validated by coimmunoprecipitation assays within the human embryonic kidney cell line HEK293, which identified the TACC2s isoform as a component consistently bound to several different members of HAT family. This raises the possibility that aberrant expression of one or more TACC proteins may affect gene regulation through their interaction with components of chromatin remodeling complexes, thus contributing to tumorigenesis.
