Dynamics of protein binding to telomeres in living cells: implications for telomere structure and function.
Telomeric proteins have an essential role in the regulation of the length of the telomeric DNA tract and in protection against end-to-end chromosome fusion. Telomere organization and how individual proteins are involved in different telomere functions in living cells is largely unknown. By using green fluorescent protein tagging and photobleaching, we investigated in vivo interactions of human telomeric DNA-binding proteins with telomeric DNA. Our results show that telomeric proteins interact with telomeres in a complex dynamic fashion: TRF2, which has a dual role in chromosome end protection and telomere length homeostasis, resides at telomeres in two distinct pools. One fraction ( approximately 73%) has binding dynamics similar to TRF1 (residence time of approximately 44 s). Interestingly, the other fraction of TRF2 binds with similar dynamics as the putative end-protecting factor hPOT1 (residence time of approximately 11 min). Our data support a dynamic model of telomeres in which chromosome end-protection and telomere length homeostasis are governed by differential binding of telomeric proteins to telomeric DNA.
Mattern
Karin A
KA
Department of Hematology, Erasmus MC, 3000DR Rotterdam, The Netherlands.
Swiggers
Susan J J
SJ
Nigg
Alex L
AL
Löwenberg
Bob
B
Houtsmuller
Adriaan B
AB
Zijlmans
J Mark J M
JM
D049452:Green Fluorescent Proteins; D006367:HeLa Cells; D006801:Humans; D007700:Kinetics; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D000089804:Shelterin Complex; D016615:Telomere / Q000235:genetics* / Q000378:metabolism*; D034501:Telomere-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D035321:Telomeric Repeat Binding Protein 1 / Q000235:genetics / Q000378:metabolism; D035341:Telomeric Repeat Binding Protein 2 / Q000235:genetics / Q000378:metabolism
D008164:Luminescent Proteins; C440849:POT1 protein, human; D011993:Recombinant Fusion Proteins; D000089804:Shelterin Complex; D034501:Telomere-Binding Proteins; D035321:Telomeric Repeat Binding Protein 1; D035341:Telomeric Repeat Binding Protein 2; D049452:Green Fluorescent Proteins