Regulation of transcription is an interface between cell growth and HIV stimulated gene expression

The transcription of chromosomal DNA into messenger RNA (mRNA) is a central process of eukaryotic gene expression. Shortly after initiation, transcription is paused by inhibition of the positive transcription elongation factor P-TEFb. This arrest acts as a control step before productive elongation of mature mRNA molecules takes place. P-TEFb is regulated by the protein Hexim1 and the small nuclear RNA 7SK. Scientists from MPI of Molecular Physiology in Dortmund have analysed the interaction between P-TEFb and its regulatory factors on a molecular level and shown, how the HIV Tat protein relieves this arrest to stimulate gene expression and production of viral proteins.