HIV-infected T cell FLICKR, NIAID HIV leads to AIDS primarily because the virus destroys essential immune cells called CD4 T cells, but precisely how these cells are killed has not been clear. Two papers published simultaneously today (December 19) in Nature and Science reveal the molecular mechanisms that cause the death of most CD4 T cells in lymphoid tissues, the main reservoir for such cells, during infection.
Transcription is carried out by an enzyme called RNA polymerase and a number of accessory proteins called transcription factors. Transcription factors can bind to specific DNA sequences called enhancer and promoter sequences in order to recruit RNA polymerase to an appropriate transcription site. Together, the transcription factors and RNA polymerase form a complex called the transcription initiation complex.
DNA Transcription. 1  RNA Polymerase Binds to DNA. 2  DNA is transcribed by an enzyme called RNA polymerase. 3  Specific nucleotide sequences tell RNA polymerase where to begin and where to end. 4  RNA polymerase attaches to the DNA at a specific area called the promoter region. 5  Elongation.