What are telomerases which plays a role in DNA replication?
Telomerase is a RNA dependent DNA polymerase that is expressed in stem cells and most cancer cells, but not in somatic cells. Using an RNA template, telomerase adds GT-rich hexanucleotide repeat sequences ranging from a few hundred (yeast) to several thousand (humans) nucleotides in length to the ends of linear DNA molecules to restore their telomeres to full length. Must know: Telomeres are composed of long strings of GT-rich hexanucleotide repeats that cap the ends of eukaryotic chromosomes. The telomeres at the ends of eukaryotic chromosomes progressively shoen with each cycle of replication. Ref: Kennelly P.J. (2011). Chapter 54. The Biochemistry of Aging. In D.A. Bender, K.M. Botham, P.A. Weil, P.J. Kennelly, R.K. Murray, V.W. Rodwell (Eds), Harper's Illustrated Biochemistry, 29e.
DNA dependent DNA polymerase
RNA dependent DNA polymerase
DNA dependent RNA polymerase
RNA dependent RNA polymerase