Exon arrays from HeLa cells transfected with RBM4-specific siRNA

RBM4 is a RNA-binding protein (RBP) able to modulate splicing by promoting exon inclusion and shares an import pathway with other splicing factors in the nucleus. In earlier studies we found that RBM4 interacts and colocalizes with WT1, which has been implicated in 10–15% of Wilms’ tumours and more recently in leukemya, is considered to be a tumour suppressor. RBM4, a RBP whose splicing effect is inhibited by the +KTS isoform of the tumour-suppressor/activator WT1, exhibits altered expression in different tumours, and may be essential for proliferation. Moreover, RBM4 binds to a number of RNAs of genes involved in acute myeloid leukaemia and cell cycle control. These results suggest that RBM4 may be involved in alternative splicing, tumorigenesis and particularly leukaemogenesis. To determine the endogenous transcripts that are targeted by RBM4 at the genome-wide level, we decided to perform exon microarray studies. RBM4-specific siRNA has been used for knockdown of RBM4 in HeLa cells. RNA was extracted using a Qiagen RNA extraction kit from untransfected, mock and siRNA-transfected HeLa cells and quality of RNA for microarray analysis was checked using a Bioanalyzer 2100 (Agilent Technologies). Experiments were run in triplicates.