Hansenula polymorpha Tert: a telomerase catalytic subunit isolated in recombinant form with limited reverse transcriptase activity

Telomerase is a ribonucleoprotein, the main function of which is to synthesize telomeres, i.e. repetitive sequences which are localized at the ends of eukaryotic chromosomes. Telomerase maintains the stability of the genome in eukaryotic cells by replicating chromosomal ends. The structural and functional investigation of the telomerase complex is significantly restricted due to difficulties connected with the isolation of its main catalytic subunit in recombinant form. Herein, we describe a method developed for the isolation of the recombinant telomerase reverse transcriptase from thermotolerant yeast Hansenula polymorpha. A functional test performed for the isolated protein and the RNA/DNA duplex, simulating the interaction of telomerase RNA and telomere, reveals that the isolated catalytic subunit of telomerase possesses limited reverse transcriptase activity.