Telomerase: Difference between revisions

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== Introduction ==

The '''telomerase''' is a complex composed of a '''Telomerase RNA''' primer and protein ~~'''telomerase reverse transcriptase'''~~ that adds G-rich repeated DNA sequences to a 3' DNA strand in eukaryotic cells <ref name='complex'>DOI: 10.1146/annurev.bi.61.070192.000553</ref>. This ribonucleoprotein acts as a reverse transcriptase that creates a DNA sequence complementary to its RNA primer in its catalytic subunit, TERT <ref name='end'>DOI: 10.1002/anie.201002387</ref>. The sequences attached to the end of DNA is non-coding DNA that functions as protection from mutation and degradation. As DNA replications occurs, the polymerase that copies in the 5' to 3' direction, cannot copy the end of the lagging strand which leaves unpaired bases that may code for a specific gene <ref name='corey'>DOI 10.1016/j.chembiol.2009.12.001</ref>. Multiple unpaired ends can form hydrogen bonds or even swap genetic material. The telomerase fixes this issue and lengthens the strands, because the replication process slowly shortens the ends of chromosomes. This enzyme also plays a role in coordinating cell division. Complementary issues of aging and cancer describe the inactivation or over-activation of telomerase activity <ref name='corey'/>.

The '''telomerase''' is a complex composed of a '''Telomerase RNA''' primer and protein [[Telomerase Reverse Transcriptase]] that adds G-rich repeated DNA sequences to a 3' DNA strand in eukaryotic cells <ref name='complex'>DOI: 10.1146/annurev.bi.61.070192.000553</ref>. This ribonucleoprotein acts as a reverse transcriptase that creates a DNA sequence complementary to its RNA primer in its catalytic subunit, TERT <ref name='end'>DOI: 10.1002/anie.201002387</ref>. The sequences attached to the end of DNA is non-coding DNA that functions as protection from mutation and degradation. As DNA replications occurs, the polymerase that copies in the 5' to 3' direction, cannot copy the end of the lagging strand which leaves unpaired bases that may code for a specific gene <ref name='corey'>DOI 10.1016/j.chembiol.2009.12.001</ref>. Multiple unpaired ends can form hydrogen bonds or even swap genetic material. The telomerase fixes this issue and lengthens the strands, because the replication process slowly shortens the ends of chromosomes. This enzyme also plays a role in coordinating cell division. Complementary issues of aging and cancer describe the inactivation or over-activation of telomerase activity <ref name='corey'/>.

== History ==

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The reverse transcription process begins by the telomerase RNA binding to the 3' end of the overhanging DNA sequence. Once primed, the G-rich sequence (~6-8 nucleotides) polymerizes the end of the DNA. The RNA primer then translocates down the new DNA sequence and polymerizes again. This process repeats until the entire telomere is formed. After one side of the telomere is formed, the telomerase attaches the complementary nucleotide bases to complete the double-stranded telomere at the end of the DNA double helix.

==Telomerase 3D structures==

[[Telomerase 3D structures]]

</StructureSection>

~~==Telomerase 3D structures==~~

~~Updated on {{REVISIONDAY2}}-{{MONTHNAME|{{REVISIONMONTH}}}}-{{REVISIONYEAR}}~~

~~{{#tree:id=OrganizedByTopic|openlevels=0|~~

*Telomerase reverse transcriptase

**[[2b2a]] - TtTERT telomerase catalytic subunit (mutant) - ''Tetrahymena thermophila''

**[[2r4g]] - TtTERT telomerase catalytic subunit

**[[6d6v]] – TtTERT + telomerase-associated protein + TEB2 + RNA + DNA – Cryo EM

**[[5c9h]] - TtTERT catalytic subunit + DNA

**[[3du6]], [[3du5]] - TcTERT telomerase catalytic subunit - ''Tribolium castaneum''

**[[3kyl]] - TcTERT telomerase catalytic subunit + DNA

**[[4o26]] – TERT RNA-binding domain + RNA – rice fish

**[[4lmo]] - TERT telomerase RNA-binding domain – tiger puffer

**[[5lgf]] - TERT N-terminal - ''Ogataea polymorpha'' - NMR

**[[5ugw]] - hTERT thumb domain

**[[5cqg]] - TERT + inhibitor - red flour beetle

**[[5npt]] – TERT N-terminal – ''Ogataea polymorpha''

*Telomerase RNA

**[[2fey]] - TtTERC P2b hairpin – NMR

**[[5kmz]] - TtTERC pseudoknot – NMR

**[[2m21]] - TtTERC stem loop IV – NMR

**[[2m22]] - TtTERC helix II – NMR

**[[2mhi]] - TERC CR4/5 – medaka - NMR

**[[2m8k]] - TERC pseudoknot – ''Kluyveromyces lactis'' - NMR

**[[1q75]], [[2k96]] – hTERC P2b hairpin (mutant) – human – NMR

**[[2k95]], [[1na2]] - hTERC P2b hairpin – NMR

**[[2l3e]] - hTERC P2a P2b hairpin – NMR

**[[2qh2]] - hTERC CR7– NMR

**[[1ymo]] - hTERC stem loop IV – NMR

**[[1z31]] - hTERC Pj6 hairpin – NMR

**[[2kye]] - hTERC P6.1 hairpin – NMR

**[[2qh3]], [[2qh4]] - hTERC terminal hairpin loop – NMR

**[[5kqe]] - TERC P2b hairpin – ''Oryzias latipes'' - NMR

}}

== References ==

[[Category:Topic Page]]

Telomerase: Difference between revisions

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@@ Line 1: / Line 1: @@
 <StructureSection load='3kyl' size='350' side='right' caption='Telomerase: bound to telomeric DNA complex with Ca+2 ion (green) [[3kyl]]' scene=''>
 == Introduction ==
-The '''telomerase''' is a complex composed of a '''Telomerase RNA''' primer and protein '''telomerase reverse transcriptase''' that adds  G-rich repeated DNA sequences to a 3' DNA strand in eukaryotic cells <ref name='complex'>DOI: 10.1146/annurev.bi.61.070192.000553</ref>. This ribonucleoprotein acts as a reverse transcriptase that creates a DNA sequence complementary to its RNA primer in its catalytic subunit, TERT <ref name='end'>DOI: 10.1002/anie.201002387</ref>. The sequences attached to the end of DNA is non-coding DNA that functions as protection from mutation and degradation. As DNA replications occurs, the polymerase that copies in the 5' to 3' direction, cannot copy the end of the lagging strand which leaves unpaired bases that may code for a specific gene <ref name='corey'>DOI 10.1016/j.chembiol.2009.12.001</ref>. Multiple unpaired ends can form hydrogen bonds or even swap genetic material. The telomerase fixes this issue and lengthens the strands, because the replication process slowly shortens the ends of chromosomes. This enzyme also plays a role in coordinating cell division. Complementary issues of aging and cancer describe the inactivation or over-activation of telomerase activity <ref name='corey'/>.
+The '''telomerase''' is a complex composed of a '''Telomerase RNA''' primer and protein [[Telomerase Reverse Transcriptase]] that adds  G-rich repeated DNA sequences to a 3' DNA strand in eukaryotic cells <ref name='complex'>DOI: 10.1146/annurev.bi.61.070192.000553</ref>. This ribonucleoprotein acts as a reverse transcriptase that creates a DNA sequence complementary to its RNA primer in its catalytic subunit, TERT <ref name='end'>DOI: 10.1002/anie.201002387</ref>. The sequences attached to the end of DNA is non-coding DNA that functions as protection from mutation and degradation. As DNA replications occurs, the polymerase that copies in the 5' to 3' direction, cannot copy the end of the lagging strand which leaves unpaired bases that may code for a specific gene <ref name='corey'>DOI 10.1016/j.chembiol.2009.12.001</ref>. Multiple unpaired ends can form hydrogen bonds or even swap genetic material. The telomerase fixes this issue and lengthens the strands, because the replication process slowly shortens the ends of chromosomes. This enzyme also plays a role in coordinating cell division. Complementary issues of aging and cancer describe the inactivation or over-activation of telomerase activity <ref name='corey'/>.
 == History ==
@@ Line 27: / Line 27: @@
 The reverse transcription process begins by the telomerase RNA binding to the 3' end of the overhanging DNA sequence. Once primed, the G-rich sequence (~6-8 nucleotides) polymerizes the end of the DNA. The RNA primer then translocates down the new DNA sequence and polymerizes again. This process repeats until the entire telomere is formed. After one side of the telomere is formed, the telomerase attaches the complementary nucleotide bases to complete the double-stranded telomere at the end of the DNA double helix.
+==Telomerase 3D structures==
+[[Telomerase 3D structures]]
 </StructureSection>
-==Telomerase 3D structures==
-Updated on {{REVISIONDAY2}}-{{MONTHNAME|{{REVISIONMONTH}}}}-{{REVISIONYEAR}}
-{{#tree:id=OrganizedByTopic|openlevels=0|
-*Telomerase reverse transcriptase
-**[[2b2a]] - TtTERT telomerase catalytic subunit (mutant) - ''Tetrahymena thermophila''<br />
-**[[2r4g]] - TtTERT telomerase catalytic subunit<br />
-**[[6d6v]] – TtTERT + telomerase-associated protein + TEB2 + RNA + DNA – Cryo EM<br />
-**[[5c9h]] - TtTERT catalytic subunit + DNA<br />
-**[[3du6]], [[3du5]] - TcTERT telomerase catalytic subunit - ''Tribolium castaneum''<br />
-**[[3kyl]] - TcTERT telomerase catalytic subunit + DNA<br />
-**[[4o26]] – TERT RNA-binding domain + RNA – rice fish<br />
-**[[4lmo]] - TERT telomerase RNA-binding domain – tiger puffer<br />
-**[[5lgf]] - TERT N-terminal - ''Ogataea polymorpha'' - NMR<br />
-**[[5ugw]] - hTERT thumb domain<br />
-**[[5cqg]] - TERT + inhibitor - red flour beetle<br />
-**[[5npt]] – TERT N-terminal – ''Ogataea polymorpha''<br />
-*Telomerase RNA
-**[[2fey]] - TtTERC P2b hairpin – NMR<br />
-**[[5kmz]] - TtTERC pseudoknot – NMR<br />
-**[[2m21]] - TtTERC stem loop IV – NMR<br />
-**[[2m22]] - TtTERC helix II – NMR<br />
-**[[2mhi]] - TERC CR4/5 – medaka - NMR<br />
-**[[2m8k]] - TERC pseudoknot – ''Kluyveromyces lactis'' - NMR<br />
-**[[1q75]], [[2k96]] – hTERC P2b hairpin (mutant) – human – NMR<br />
-**[[2k95]], [[1na2]] - hTERC P2b hairpin – NMR<br />
-**[[2l3e]] - hTERC P2a P2b hairpin – NMR<br />
-**[[2qh2]] - hTERC CR7– NMR<br />
-**[[1ymo]] - hTERC stem loop IV – NMR<br />
-**[[1z31]] - hTERC Pj6 hairpin – NMR<br />
-**[[2kye]] - hTERC P6.1 hairpin – NMR<br />
-**[[2qh3]], [[2qh4]] - hTERC terminal hairpin loop – NMR<br />
-**[[5kqe]] - TERC P2b hairpin – ''Oryzias latipes'' - NMR<br />
-}}
 == References ==
 <references/>
 [[Category:Topic Page]]