Scientists, for the first time, studied the inner workings of telomerase enzyme, according to a report published on July 11, 2018.
This study was conducted by the researchers at the University of California, Los Angeles. Researchers studied in detail about the structure of telomerase’s catalytic core and also, for the first time, reported that they have captured telomerase in the process of making DNA.
The main function of telomerase is to maintain the DNA in telomeres, the structures at the ends of human chromosomes. When the cells divide, if the telomerase is not active, the telomeres get shorter every time during the division. Therefore, the telomeres eventually become so short that the cells stop dividing or die. However, cells that have with abnormally active telomerase can continually rebuild their protective chromosomal caps and will not die. Over time, this is harmful, as DNA errors will start accumulating and damaging cells. Telomerase is especially active in cancer cells, which enables growth and spreading of cancer.
Single-celled microorganisms called tetrahymena thermophile were used by the researchers to conduct the study. Telomerase’s components are relatively well-known in Tetrahymena and telomerase and telomeres were first discovered in this organism. Telomerase contains a specialized ‘reverse transcriptase’ that has four major regions and several sub-regions. In this research, the scientists have revealed a large, previously unstudied sub-region called ‘TRAP’ in the enzyme’s reverse transcriptase.
Other reverse transcriptases can copy any arbitrary RNA sequence and form DNA from it, however, telomerase’s reverse transcriptase copies only a specific six-nucleotide RNA and does so many times to make a long chain of DNA. Cryo-electron microscopy technique was used by the researchers to see the enzyme in extraordinary detail, and used computational modeling to interpret their data.