Related Experiment Video
Updated: Aug 17, 2026

Telomere Length and Telomerase Activity; A Yin and Yang of Cell Senescence
Published on: May 22, 2013
Barley telomeres shorten during differentiation but grow in callus culture
A Kilian1, C Stiff, A Kleinhofs
1Department of Crop & Soil Sciences, Washington State University, Pullman WA 99164-6420, USA.
Abstract:
Eukaryotic chromosomes terminate with long stretches of short, guanine-rich repeats. These repeats are added de novo by a specialized enzyme, telomerase. In humans telomeres shorten during differentiation, presumably due to the absence of telomerase activity in somatic cells. This phenomenon forms the basis for several models of telomere role in cellular senescence. Barley (Hordeum vulgare L.) telomeres consist of thousands of TTTAGGG repeats, closely resembling other higher eukaryotes. In vivo differentiation and aging resulted in reduction of terminal restriction fragment length paralleled by a decrease of telomere repeat number. Dedifferentiation in callus culture resulted in an increase of the terminal restriction fragment length and in the number of telomere repeats. Long-term callus cultures had very long telomeres. Absolute telomere lengths were genotype dependent, but the relative changes due to differentiation, dedifferentiation, and long-term callus culture were consistent among genotypes. A model is presented to describe the potential role of the telomere length in regulation of a cell's mitotic activity and senescence.
Related Concept Videos
Replication in Eukaryotes
Meristems and Plant Growth
Telomeres and Telomerase
Replicative Cell Senescence
Replication in Eukaryotes
Many Proteins Orchestrate Replication at the Origin
Eukaryotic replication follows many of the same...
Maintenance of the ES Cell State

