The Human Rbbp10 And Bima3 The Cloning And Functional Study

Cell proliferation and apoptosis are essential for development and tissue homeostasis. The imbalance between proliferation and apoptosis has been linked to a number of diseases. RB and bcl-2 protein family play a critical role in the biological balance. By scannimg human cDNA library for either RB binding domain or BH3 domain contained novel gene, a novel RB binding gene RBBP10 and two novel isoforms of bim were isolated.RBBP10 encodes a 182 residues putative protein and expresses ubiquitously in many human tissues in a quite low level, and the expression is high in tumor tissues. Yeast two hybridization revealed RBBP10 can bind RB, Prx 1 and a novel human gene—yrdC. Over expression of Prx 1 results in reduction of S phase cells (control: 38.23±1.98%; Prx 1+: 30.95±1.63%). Anti-senses over-expression of RBBP10 or yrdC results in reduction of S phase cells (RBBP10-: 30.67±1.42%; yrdC-: 33.53±1.00%). IHC with RBBP10 specific antibody revealed RBBP10 expressed in breast cancer cell dome. The results suggest RBBP10 might be a potential marker of tumor diagnosis.bim α3 encodes 79 residues protein contained a BH3 domain. EGFP-bimα3 fused protein gained the same subcellular location as 3 classical bim isoforms in HEK 293 cell. Overexpression of bim α3 results in cell apoptosis similar to bim α2 (bim α2: 30.14±2.66%; bim α3: 32.05±6042). Use artificial Kozak consensus sequence, we revealed bimβ5 uses a novel translated initial ATG and encodes 36 residues with a BH3 domain. A synthesis cDNA—bimβ6 encodes 28 reisdues with BH3 core sequence was built. Over-expression of bimβ5 or bim beta 6 results in cell apoptosis (bimβ5: 28.17%; bimβ6: 28.13%). The results revealed BH3 domain is both enough and necessary for mitchondrial location and apoptotic activity of bim, and the amino acids just before BH3 domain might enhance the apoptotic activity of bim. The expression pattern of bim isoforms is specific from different tissues and different differentiation state. Such an expression pattern might be a meaningful marker for determining the tissue differentiation.Over-expression of bim L results in HEK293 cell apoptosis, while AD293 cells do not apoptosis anymore. A SSH between AD293 and HEK293 presents adherin protein such as parvin and actin, anti-apoptosis protein such as PMSA3 and BTF were up-regulated in AD293. The results suggest the changed adherin and apoptosis protein expression are responsible for the different apoptosis state response to bim.