Single-stranded DNA repeat synthesis by telomerase.

The eukaryotic ribonucleoprotein reverse transcriptase (RT) telomerase uses a template within its integral RNA subunit to extend chromosome ends by synthesis of single-stranded telomeric repeats. Telomerase is adapted to its unique cellular role by an ability to release product DNA in single-stranded form, regenerating free template from the product-template hybrid. Furthermore, by retaining a template-independent grip on the single-stranded product, telomerase can catalyze processive repeat synthesis. These specialized nucleic acid handling properties are dependent on the protein and RNA domain network within an active RNP. RNP domain architecture and mechanisms for single-stranded DNA handling have been a focus of recent studies highlighted here.