Identification of additional telomerase component of the yeast H. polymorpha is a step towards understanding the complex at the atomic level

59 Telomerase is a ribonucleoprotein complex whose function is to synthesize telomeres—repeated sequences at the ends of linear chromosomes. The absence of telomerase activity in the cell causes grad ual shortening of telomeres, with the onset of senes cence after reaching the critical length. In addition to the catalytic subunit and telomerase RNA, additional components are required for the functioning of this enzyme in vivo in the yeast S. cerevisiae cells, namely, Est1 and Est3. To date, structural data for these com ponents are absent due to the instability of the pro teins.