Telomerase Essential for Mouse Stem Cells

Telomerase Essential for Mouse Stem Cells

The Johns Hopkins Gazette reports on research done at the university with stem cells and telomeres. Telomeres are a string of redundant DNA that protect chromosomes; however, each time the cell divides, some of the telomere is cut off. Eventually the telomere becomes too short, and the cells stops dividing. Stem cells are able to continue their division because they manufacture a protein called telomerase, which keeps the telomeres long.

In the Johns Hopkins research, the researchers discovered that “some” telomerase is not enough. The telomeres shortened in mice that had only half the amount of telomerase, and normal mice whose parents had reduced telomerase also had early loss of stem cell reproduction despite their normal genetic make-up.

Further, adding telomerase to mice who had shortened telomeres did not cause the shorter telomeres to get longer; once a telomere is short, there is apparently no way for it to lengthen.

The article goes on to discuss the issue as related to the human disease dyskeratosis congenita, which causes early death because the stem cells in the bone marrow stop reproducing.