In living systems, the relative amounts of any protein are controlled at many levels. For example, amounts are affected by protein degradation, regulation of the translational rates of polypeptide synthesis (translational regulation), and control of the rates of mRNA synthesis (transcriptional regulation). Transcriptional regulation involves modulation of the rate-limiting enzyme RNA polymerase. DSIF (DRB sensitivity-inducing factor) is a heterodimeric transcription elongation protein. It is composed of a large subunit of 160 kDa and a small subunit of 14 kDa. These large and the small subunits are homologs of the yeast gene products Stp5 and Stp4, respectively. Spt4 and 5 are transcription factors which are critically important for the activity of RNA polymerase. In conjunction with DRB, DSIF attenuates RNA polymerase II elongation steps. However, in limiting amounts of ribonucleotides, DSIF, by itself, stimulates the elongation rate of RNA polymerase II. Thus, the identification of a human regulator for transcriptional elongation will greatly enhance our understanding of this critical step in mammalian gene expression.
This antibody is routinely tested by western blot analysis. Other applications were tested at BD Biosciences Pharmingen during antibody development only or reported in the literature.