SYNTHETIC OCTAPEPTIDE PYROGLU-ASP-ASP-SER-ASP-GLU-GLU-ASN CONTROLS DNA-TRANSCRIPTION IN-VITRO BY RNA POLYMERASE-II

The effect of the synthetic octapeptide pyroGLU-ASP-ASP-SER-ASP-GLU-GL U-ASN (phosphorylated by casein kinase II, CKII) on DNA transcription by RNA polymerase II has been studied. The peptide contains the acidic carboxy-terminus heptapeptide of the largest subunit of RNA polymeras e II, which has been demonstrated to be a phosphorylation site for CKI I. The aim of this work is to obtain some insights about the possible role of this domain in RNA polymerase II activity and DNA binding. Res ults demonstrated that the phosphorylated octapeptide causes strong in hibition of transcription of calf thymus DNA or pSVL SV40 plasmid DNA by RNA polymerase IL, when used at concentrations between 0.4-4 mug/ml .