hnRNP A2B1: Lysates

RNA polymerase II transcripts in the nucleus are in complex with several different proteins called heterogeneous nuclear ribonucleoproteins (hnRNPs). These proteins act in biological activities such as transcription, pre-mRNA processing, cytoplasmic mRNA ranslation, and turnover.2. hnRNPs can be isolated either by immunoprecipitation or by sucrose gradient fractionation of cell extracts. Isolated hnRNPs consist of protein groups named A to U and many of these protein groups consist of more than one isoform.3 The major steadystate proteins of the isolated hnRNP complex are the A1, A2, B1, B2, C1, and C2 with a range of molecular weights (34-43 kDa).3 hnRNP-A2/B1 proteins are located in the nucleus of most tissues cells; however, the hnRNP-A2 protein is found also in the cytoplasm of skin and esophagus cells. In rat brain, hnRNP-A2/B1 proteins are found in neurons in the cerebral cortices, hippocampal formation, olfactory regions, caudate-putamin, and the supraoptic ucleus of the hypothalamus.4 Expression of hnRNP-A2/B1 proteins was found also in lung development and its over expression correlated with lung cancer.5