Rb Antibody / Retinoblastoma

Rb restricts the cell's ability to replicate DNA by preventing its progression from the G1 (first gap phase) to S (synthesis phase) phase of the cell division cycle. Rb binds and inhibits transcription factors of the E2F family, which are composed of dimers of an E2F protein and a dimerization partner (DP) protein. The transcription activating complexes of E2 promoter-binding–protein-dimerization partners (E2F-DP) can push a cell into S phase. As long as E2F-DP is inactivated, the cell remains stalled in the G1 phase. When Rb is bound to E2F, the complex acts as a growth suppressor and prevents progression through the cell cycle. The Rb-E2F/DP complex also attracts a histone deacetylase (HDAC) protein to the chromatin, reducing transcription of S phase promoting factors, further suppressing DNA synthesis.[Wiki] mAb 1F8 ecognizes a 105kDa phosphoprotein, identified as retinoblastoma (Rb) gene product. It shows no cross reaction with p107 or p130. It specifically stains the nuclei of BT-20 cells and primary human foreskin fibroblast (HFF) cells. It does not stain the Rb-negative BT549 cells. It reacts with the hyperphosphorylated as well as the un (under) phosphorylated form of the Rb protein.