TELOMERASE

Illustration of the vertebrate telomerase ribonucleoprotein complexed with its substrate, telomeric DNA (blue). Telomerase consists of a reverse transcriptase (TERT, red), RNA component (TR, green), and the dyskerin protein complex (blue). The TERT protein contains the essential telomerase N-terminal domain (TEN, pink), telomerase RNA-binding domain (TRBD, light red), the reverse transcriptase domain (RT, red), and the C-terminal extension (CTE, dark red). TR contains base-pairing region P1b that defines the template boundary, the template that encodes the telomeric DNA repeat sequence, the pseudoknot, conserved regions 4 and 5 (CR4/5) that include P6 and P6.1, and the 3'-proximal H/ACA stem-loops each bound by a dyskerin complex. The dyskerin complex is composed of dyskerin (light blue), Nop10 (sky blue), NHP2 (violet), and Gar1 (dark blue). The pseudoknot is believed to be bound by TEN while P6/P6.1 is bound by TRBD . Six proteins associate with telomeric DNA and form the shelterin..