This domain is found at the C-terminal end of Telomerase reverse transcriptase (TERT), a ribonucleoprotein enzyme essential for the replication of chromosome termini in most eukaryotes. This entry represents the C-terminal extension (also known as th ...
This domain is found at the C-terminal end of Telomerase reverse transcriptase (TERT), a ribonucleoprotein enzyme essential for the replication of chromosome termini in most eukaryotes. This entry represents the C-terminal extension (also known as the thumb domain), which forms an all helical bundle. There are three conserved motifs in this domain involved in nucleic acid binding. In humans, single mutations localised within this portion of telomerase are associated with several bone marrow failure syndromes [1,2].
Reverse transcriptase (RNA-dependent DNA polymerase)
A reverse transcriptase gene is usually indicative of a mobile element such as a retrotransposon or retrovirus. Reverse transcriptases occur in a variety of mobile elements, including retrotransposons, retroviruses, group II introns, bacterial msDNAs ...
A reverse transcriptase gene is usually indicative of a mobile element such as a retrotransposon or retrovirus. Reverse transcriptases occur in a variety of mobile elements, including retrotransposons, retroviruses, group II introns, bacterial msDNAs, hepadnaviruses, and caulimoviruses.
Telomeres in most organisms are comprised of tandem simple sequence repeats [1]. The total length of telomeric repeat sequence at each chromosome end is determined in a balance of sequence loss and sequence addition [1]. One major influence on telome ...
Telomeres in most organisms are comprised of tandem simple sequence repeats [1]. The total length of telomeric repeat sequence at each chromosome end is determined in a balance of sequence loss and sequence addition [1]. One major influence on telomere length is the enzyme telomerase [1]. It is a reverse transcriptase that adds these simple sequence repeats to chromosome ends by copying a template sequence within the RNA component of the enzyme [1]. The RNA binding domain of telomerase - TRBD - is made up of twelve alpha helices and two short beta sheets [2]. How telomerase and associated regulatory factors physically interact and function with each other to maintain appropriate telomere length is poorly understood. It is known however that TRBD is involved in formation of the holoenzyme (which performs the telomere extension) in addition to recognition and binding of RNA [2].
TPP1 is a component of the telomerase holoenzyme, involved in telomere replication. It has been demonstrated that TPP1 dimerises and binds to DNA and RNA. Furthermore, TPP1 stimulates the dissociation of RNA/DNA hetero-duplexes [1,2]. Yeast telomera ...
TPP1 is a component of the telomerase holoenzyme, involved in telomere replication. It has been demonstrated that TPP1 dimerises and binds to DNA and RNA. Furthermore, TPP1 stimulates the dissociation of RNA/DNA hetero-duplexes [1,2]. Yeast telomerase protein TPP1 (Est3 in yeast) is a novel type of GTPase [3]. The key residues in Swiss:Q03096 are an Asp at residue 86 and the Arg at residue 110. The Asp is totally conserved in the family, whereas the Arg is not so well conserved. The N-terminal of TPP1 is likely to be the binding surface for TINF2, whereas the C-terminus probably binds to POT1, thereby tethering POT1 to the shelterin complex [4]. The complex bound to telomeric DNA increases the activity and processivity of the human telomerase core enzyme, thus helping to maintain the length of the telomeres [5,6]. This domain is conserved from fungi to mammals, hence family Telomere_Pot1 has been merged into the family [7]. The human shelterin complex includes six proteins: telomere repeat binding factor 1 (TRF1), TRF2, repressor/activator protein 1 (RAP1), TRF1-interacting nuclear protein 2 (TIN2), TIN2-interacting protein 1 (TPP1) and protection of telomeres 1 (POT1) [8].
