3d1d: Difference between revisions
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< | ==Hexagonal crystal structure of Tas3 C-terminal alpha motif== | ||
<StructureSection load='3d1d' size='340' side='right'caption='[[3d1d]], [[Resolution|resolution]] 2.60Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[3d1d]] is a 6 chain structure with sequence from [https://en.wikipedia.org/wiki/Schizosaccharomyces_pombe Schizosaccharomyces pombe]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3D1D OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3D1D FirstGlance]. <br> | |||
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.6Å</td></tr> | |||
-- | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=3d1d FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3d1d OCA], [https://pdbe.org/3d1d PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3d1d RCSB], [https://www.ebi.ac.uk/pdbsum/3d1d PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3d1d ProSAT]</span></td></tr> | ||
</table> | |||
== Function == | |||
[https://www.uniprot.org/uniprot/TAS3_SCHPO TAS3_SCHPO] Has a role in the RNA interference (RNAi) pathway which is important for heterochromatin formation and accurate chromosome segregation. A member of the RNA-induced transcriptional silencing (RITS) complex which is involved in the biosynthesis of dsRNA from primer siRNAs provided by the RNA-directed RNA polymerase (RDRC) complex.<ref>PMID:15607976</ref> <ref>PMID:14704433</ref> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
RNA interference (RNAi) plays a pivotal role in the formation of heterochromatin at the fission yeast centromeres. The RNA-induced transcriptional silencing (RITS) complex, composed of heterochromatic small interfering RNAs (siRNAs), the siRNA-binding protein Ago1, the chromodomain protein Chp1, and the Ago1/Chp1-interacting protein Tas3, provides a physical tether between the RNAi and heterochromatin assembly pathways. Here, we report the structural and functional characterization of a C-terminal Tas3 alpha-helical motif (TAM), which self-associates into a helical polymer and is required for cis spreading of RITS in centromeric DNA regions. Site-directed mutations of key residues within the hydrophobic monomer-monomer interface disrupt Tas3-TAM polymeric self-association in vitro and result in loss of gene silencing, spreading of RITS, and a dramatic reduction in centromeric siRNAs in vivo. These results demonstrate that, in addition to the chromodomain of Chp1 and siRNA-loaded Ago1, Tas3 self-association is required for RITS spreading and efficient heterochromatic gene silencing at centromeric repeat regions. | |||
An alpha motif at Tas3 C terminus mediates RITS cis spreading and promotes heterochromatic gene silencing.,Li H, Motamedi MR, Yip CK, Wang Z, Walz T, Patel DJ, Moazed D Mol Cell. 2009 Apr 24;34(2):155-67. PMID:19394293<ref>PMID:19394293</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
== | </div> | ||
<div class="pdbe-citations 3d1d" style="background-color:#fffaf0;"></div> | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
[[Category: Large Structures]] | |||
[[Category: Schizosaccharomyces pombe]] | [[Category: Schizosaccharomyces pombe]] | ||
[[Category: Li | [[Category: Li H]] | ||
[[Category: Patel | [[Category: Patel DJ]] | ||
Latest revision as of 15:37, 30 August 2023
Hexagonal crystal structure of Tas3 C-terminal alpha motifHexagonal crystal structure of Tas3 C-terminal alpha motif
Structural highlights
FunctionTAS3_SCHPO Has a role in the RNA interference (RNAi) pathway which is important for heterochromatin formation and accurate chromosome segregation. A member of the RNA-induced transcriptional silencing (RITS) complex which is involved in the biosynthesis of dsRNA from primer siRNAs provided by the RNA-directed RNA polymerase (RDRC) complex.[1] [2] Publication Abstract from PubMedRNA interference (RNAi) plays a pivotal role in the formation of heterochromatin at the fission yeast centromeres. The RNA-induced transcriptional silencing (RITS) complex, composed of heterochromatic small interfering RNAs (siRNAs), the siRNA-binding protein Ago1, the chromodomain protein Chp1, and the Ago1/Chp1-interacting protein Tas3, provides a physical tether between the RNAi and heterochromatin assembly pathways. Here, we report the structural and functional characterization of a C-terminal Tas3 alpha-helical motif (TAM), which self-associates into a helical polymer and is required for cis spreading of RITS in centromeric DNA regions. Site-directed mutations of key residues within the hydrophobic monomer-monomer interface disrupt Tas3-TAM polymeric self-association in vitro and result in loss of gene silencing, spreading of RITS, and a dramatic reduction in centromeric siRNAs in vivo. These results demonstrate that, in addition to the chromodomain of Chp1 and siRNA-loaded Ago1, Tas3 self-association is required for RITS spreading and efficient heterochromatic gene silencing at centromeric repeat regions. An alpha motif at Tas3 C terminus mediates RITS cis spreading and promotes heterochromatic gene silencing.,Li H, Motamedi MR, Yip CK, Wang Z, Walz T, Patel DJ, Moazed D Mol Cell. 2009 Apr 24;34(2):155-67. PMID:19394293[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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