Terminal deoxyribonucleotide transferase

The problem of telomere shortening is solved by an enzyme that adds telomeric sequences to the ends of each chromosome. The enzyme is a protein and RNA complex called telomere terminal transferase, or telomerase. Because the sequence of the telomerase-associated RNA, as we will see, serves as the template for addition of deoxyribonucleotides to the ends of telomeres, the source of the enzyme and not the source of the telomeric DNA primer determines the sequence added. This was proved by transforming Tetrahy mena with a mutated form of the gene encoding the... 

F g. 6. In vitro generation of a chimeric plasmid containing foreign DNA. Sticky ends are created by the action of terminal transferase and an appropriate deoxyribonucleotide triphosphate. 

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