Telomerase-mediated telomere maintenance counteracts the end replication problem due to the incomplete replication of the linear DNA ends by conventional DNA polymerases and in turn helps prevent chromosome instability ( 2). It is a specialized reverse transcriptase with an integral RNA component that extends the telomeric DNA by adding repetitive TG-rich sequence to the 3′ termini ( 1). Telomerase, a multi-subunit ribonucleoprotein (RNP) enzyme, is a key player for telomere maintenance and helps enable unlimited cell proliferation. The telomere is the nucleoprotein complex at the chromosome end and is essential for genome integrity and chromosome stability. brucei suggest that important conformational changes are a key component of T. Our observed differences in RNA (TR) folding at two distinct developmental stages of T. brucei exists in a conformationally preorganized stable structure. Also, TERT does not significantly affect the RNA folding in vivo, suggesting that the telomerase RNA in T. We discover that TR forms at least two different conformers with distinct folding topologies in the insect and mammalian developmental stages of T. For this purpose, we uniquely combined in-cell probing with targeted high-throughput RNA sequencing and mutational mapping under three conditions: in vivo (in WT and TERT −/− cells), in an immunopurified catalytically active telomerase RNP complex and ex vivo (deproteinized). TR template, template boundary element, template proximal helix and Helix IV (eCR4-CR5) domain. Here, using unicellular pathogen Trypanosoma brucei as a model, we reveal important regional folding information of the native telomerase RNA core domains, i.e. However, how telomerase RNA folding takes place in vivo has not been fully understood due to low abundance of the native RNP. The 5’-half of TR forms a highly conserved catalytic core comprising of the template region and adjacent domains necessary for telomere synthesis. Telomerase contains the reverse transcriptase protein, TERT and the template RNA, TR, as its core components. Telomerase is a unique ribonucleoprotein (RNP) reverse transcriptase that utilizes its cognate RNA molecule as a template for telomere DNA repeat synthesis.
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