Hiding telomerase from chromatin

Telomerase helps cancerous cells survive by extending telomeres at the end of chromosomes. According to new results from Judy Wong, Leonard Kusdra, and Kathleen Collins (University of California, Berkeley, CA), cancer cells recruit additional telomerase by setting it free from its subnuclear storage depot.

Telomerase is activated upon association of two subunits, telomerase reverse transcriptase (TERT) and telomerase RNA, into a ribonucleoprotein (RNP) complex. Collins' group tracked the active form in normal and cancerous cells by expressing GFP-labeled TERT in limiting amounts that would assemble rapidly with the RNP. This technique revealed that telomerase differed mainly in its location. “A normal cell hides telomerase, by tying it to the nucleolus,” says Collins. In these cells, telomerase was concentrated in the nucleoplasm during S phase, when its activity is required to maintain chromosome ends. In...