Table 3.
Comparative overview of proteins associated with telomeric double strand DNA (dsDNA).
| Telomeric dsDNA Associated Proteins | |||||
|---|---|---|---|---|---|
| Human Telomeric dsDNA Associated Proteins | Protein Function and Direct Interactions | References | Arabidopsis Telomeric dsDNA Associated Proteins | Protein Function and Direct Interactions | References |
| TRF1 | Shelterin. Int.: telomeric dsDNA, TIN2, TANK1 and PINX1. Non-telomeric: binding to ITS and chromatin and satellite DNA and modulation of their chromatin structure. Control of a common fragile site containing ITS. |
[59,60,61,62] [162,182] |
TRB1, 2, 3 | Shelterin-like. Int.: telomeric dsDNA, TERT, POT1b, RuvBL1 and RuvBL2a. Non-telomeric functions - a recruitment subunit of protein complexes involved in epigenetic regulations. Binding to ITSs. |
[64,65,66]; Schorova et al., submitted [67,68,69,70,71] |
| TRF2 | Shelterin. Int.: telomeric dsDNA; TIN2, RAP1, NBS1, RAD50, Apollo, Ku70, PARP1, XPF-ERCC1, BLM, FEN1, POLB, ORC, RTEL1 and ATM. | [61,72,73,74,75,76,77,78,79,80,183,184,185,186,187] | TRP1 | Possible non-telomeric functions of telomerase. Int.: telomere dsDNA in vitro, TERT, ARM, Ku70, TRFL1 and TRFL9. | [66,69,81,82,83] |
| Non-telomeric function: transcriptional regulator. Binding to ITSs and satellite III. | [155,163] | TRFL2 | Possible non-telomeric functions of telomerase. Int.: telomere dsDNA in vitro, TERT and ARM. | [69,83] | |
| TRFL9 | Possible non-telomeric functions of telomerase. Int.: telomere dsDNA in vitro, TRP1 and POT1a. | [69,83] | |||
| TBP1, TRFL1, TRFL4 | Int.: telomere dsDNA in vitro. | [83,188] | |||
| HOT1 | Int.: telomeric dsDNA, active telomerase. | [93] | n.a. | ||
| Ku70/80 | The way of association with telomeric dsDNA is not fully elucidated. Int.: TRF2, RAP1, TR and TERT. | [95] | Ku70/80 | Role in telomere length regulation, may protect blunt-ended telomeres Int.: TRP1, TER2 and TER2s. | [82,96,97,98,99,101] |
The proteins depicted in grey are involved in telomere maintenance, however, their association with telomeric dsDNA has not been fully proven yet. Direct interaction partners (Int.) interacting with telomeric dsDNA-associated proteins and concerning their telomeric functions are enumerated. No sequence homologue has been identified yet (n.a.). Double-strand DNA (dsDNA); 5′ exonuclease Apollo (Apollo); Armadillo/β-catenin-like repeat-containing protein (ARM); Ataxia telangiectasia mutated kinase (ATM); ATP-dependent DNA helicase 2 subunit 1 and 2 (Ku70/80); Bloom syndrome protein (BLM); DNA polymerase beta (POLB); DNA repair protein RAD50 (RAD50); Excision repair cross-complementation 1 (ERCC1); Flap endonuclease 1 (FEN1); Homeobox telomere-binding protein 1 (HOT1); Interstitial telomeric sequences (ITSs); Nijmegen breakage syndrome protein 1 (NBS1); Origin recognition complex (ORC); Poly(ADP-Ribose); polymerase 1 (PARP1); Protection of telomeres 1b (POT1b); Regulator of telomere elongation helicase 1 (RTEL1); Repressor-activator protein 1 (RAP1); Telomerase RNA (TR); RuvB-like 1, 2a (RuvBL1, 2a); Tankyrase 1 (TANK1); Telomerase reverse transcriptase (TERT); Telomerase RNA subunit 2, 2s (TER2, TER2s); Telomere binding protein 1 (TBP1); Telomere repeat-binding factor 1, 2, 3 (TRB1, 2, 3); Telomere repeat-binding protein 1 (TRP1); Telomeric repeat binding Factor 1-like 1, 2, 4, 9 (TRFL1, 2, 4, 9); Telomeric repeat-binding factor 1 (TRF1); Telomeric repeat-binding factor 2 (TRF2); TRF1-interacting nuclear protein 2 (TIN2); TRF1-interacting protein 1 (PINX1); Xeroderma pigmentosum group F (XPF1).