Telomerase And Alternative Lengthening Of Telomeres Coexist In The Regenerating Zebrafish Caudal Fins
Our bodies are made of cells, and inside each cell are chromosomes that carry our genetic information. At the very ends of these chromosomes are special protective caps called telomeres. Think of them like the plastic tips on shoelaces, preventing the shoelaces from fraying. Every time a cell divides, these telomeres get a little shorter, which is a natural part of aging.
To counteract this shortening, cells have an enzyme called telomerase, which helps to rebuild and maintain telomere length. However, some cells, especially those undergoing rapid division, can also use an “Alternative Lengthening of Telomeres” (ALT) pathway, which is like a backup system that repairs and lengthens telomeres without needing the telomerase enzyme.
New research looking at how zebrafish regenerate their fins has shed light on these fascinating processes. Scientists found that during fin regrowth, which involves a lot of cell division, zebrafish utilize both telomerase and the ALT pathway to keep their telomeres in good shape. This is crucial for the continuous high rate of cell proliferation needed for regeneration. Interestingly, even in zebrafish that were engineered to lack telomerase, their fins could still regenerate effectively because the ALT pathway stepped in to maintain telomere length. This shows that these two mechanisms can work together or independently to ensure that chromosomes remain protected during periods of intense tissue repair and growth.