Mapping of interaction domains of putative telomere‐binding proteins AtTRB1 and AtPOT1b from Arabidopsis thaliana

Abstract

We previously searched for interactions between plant telomere-binding proteins and found that AtTRB1, from the single-myb-histone (Smh) family, interacts with the Arabidopsis POT1-like-protein, AtPOT1b, involved in telomere capping. Here we identify domains responsible for that interaction. We also map domains in AtTRB1 responsible for interactions with other Smh-family-members. Our results show that the N-terminal OB-fold-domain of AtPOT1b mediates the interaction with AtTRB1. This domain is characteristic for POT1-proteins and is involved with binding the G-rich-strand of telomeric DNA. AtPOT1b also interacts with AtTRB2 and AtTRB3. The central histone-globular-domain of AtTRB1 is involved with binding to AtTRB2 and 3, as well as to AtPOT1b. AtTRB1-heterodimers with other Smh-family-members are more stable than AtTRB1-homodimers. Our results reveal interaction networks of plant telomeres.

Functional characterization of domains in AtTRB1, a putative telomere-binding protein in Arabidopsis thaliana

“…2 and 4b. Moreover, the H1/5 domain of AtTRB proteins was recently shown to interact with the OB-fold domain of the AtPOT1b telomeric protein (Prochazkova Schrumpfova et al, 2008) suggesting yet another mode of AtTRB recruitment to telomeres. Interestingly, our results do not show any important role of the coiled-coil domain of AtTRB1 in the interactions studied, although this domain was originally suggested as responsible for protein-protein interactions (Marian et al, 2003).…”

QTL Mapping and Candidate Gene Analysis of Telomere Length Control Factors in Maize (Zea maysL.)

“…Relatedly, mammalian TRF1 recruits POT1 to the telomeres, where it caps the 3′ end (Loayza and De Lange 2003). In plants, Arabidopsis SMH telomere-binding proteins have been shown by means of yeast two-hybrid assays to associate with plant homologs of POT1 (Kuchar and Fajkus 2004; Schrumpfova et al 2008). Furthermore, POT1 proteins from several plants bind single-stranded telomeric DNA in vitro (Shakirov et al 2009, 2010), whereas other members of the plant POT1 family, notably At POT1, appear instead to interact with the telomerase RNA (Cifuentes-Rojas et al 2011).…”

“…At least two families of plant-telomere double-strand DNA-binding proteins, RTBP1/TRFL and SMH, have been identified as having TRF-like single-myb DNA-binding domains (Yu et al 2000; Marian et al 2003). Some of these putative homologs of mammalian TRF proteins exhibit protein-protein interactions with other telomeric proteins (Kuchar and Fajkus 2004; Schrumpfova et al 2008). The CST complex, found in animals, yeast, and plants, functions to maintain telomeric integrity, structure, and uniform length (Miyake et al 2009; Surovtseva et al 2009).…”

Molecular inhibition of telomerase recruitment using designer peptides: anin silicoapproach

“…POT1a is associated with telomerase and is required for synthesis while POT1b and POT1c are involved in chromosome-end protection (Rossignol, Collier, Bush, Shaw, & Doonan, 2007). POT1b is a member of shelterin complex and a homolog of telomeric Goverhang binding proteins and is similar to mammalian shelterin complex (Kuchař & Fajkus, 2004) which has been reported to physically interact with telomere repeat binding AtTRB1, AtTRB2, and AtTRB3 (Jaiswal, 2014;Schrumpfová, Kuchar, Palecek, & Fajkus, 2008;Schrumpfová et al, 2014). Arabidopsis possesses approximately 20-30 nucleotides long G-overhang which is recognized by POT1 to act upon.…”