Journal of Cell Science 116, e904 (2003)
Copyright © 2003 The Company of Biologists Limited
Telomerase weighs anchor
Telomeres are replicated by the enzyme telomerase, a ribonucleoprotein that
adds telomeric repeats to the 3' ends of chromosomes. The biochemistry
of this reaction has been established, but how the end-replication machinery
is organized in vivo and what the roles of telomerase-associated proteins such
as p43 are remain obscure. Hans Lipps and co-workers have therefore
investigated this in Euplote, a spirotrichous ciliate whose
macronucleus has numerous telomeres (see
p. 1757). They demonstrate
that telomerase and p43 form complexes that are anchored to the nuclear matrix
by p43. Electroelution experiments indicate that the telomerase and p43 remain
associated with the nuclear matrix whereas the telomeric sequences themselves
are released during replication. Using RNAi for the first time in a
spirotrich, the authors go on to demonstrate that removal of p43 or telomerase
not only prevents the proteins from associating with the nuclear matrix but
also produces nuclear defects likely to be caused by defective DNA
replication. They suggest that binding of telomerase induces a structural
change in p43 that allows it to anchor the p43-telomerase complex on the
nuclear matrix, where the enzymatic complex must reside to function
efficiently.
Related articles in JCS:
- The telomerase-associated protein p43 is involved in anchoring telomerase in the nucleus
- Matthias Möllenbeck, Jan Postberg, Katrin Paeschke, Michael Rossbach, Franziska Jönsson, and Hans J. Lipps
JCS 2003 116: 1757-1761.
[Abstract]
[Full Text]
