Telomerase was discovered as the enzyme deputed to telomeremaintenance. In human somatic cells, its activity is virtually absent, andcells stop proliferating when telomeres fall below a critical length. Incontrast, in the vast majority of tumors, telomerase is active and itsactivity is associated with telomere preservation and with the acquisitionof an unlimited proliferative potential. Despite this well known andconsolidated role of telomerase, a large body of evidence indicates that itcontributes to cellular physiology independently of telomere lengthmaintenance. Multiple roles of telomerase in cancer development havebeen highlighted, besides telomere lengthening, among which is geneexpression regulation. More recently, the telomerase catalytic subunit hasbeen shown to associate with an RNA molecule different from thetelomerase RNA, giving rise to a complex with functions unrelated totelomere metabolism. Besides telomerase, telomeric proteins play afundamental role in telomere maintenance. In particular, a six proteincomplex, named shelterin, is stably associated with telomeres and isessential for telomere metabolism. As well as for telomerase, additionalroles beyond telomeres have been found for telomeric proteins, inparticular for the TRF2 subunit of shelterin. In this review, we willdiscuss extra-telomeric functions of telomerase and TRF2 in differentbiological processes.
|Title of host publication||Telomerase: Composition, Functions and Clinical Implications|
|Publisher||Nova Science Publishers, Inc.|
|Number of pages||24|
|Publication status||Published - 2010|
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)