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Functional Evolution in Orthologous Cell-encoded RNA-dependent RNA Polymerases
| Content Provider | Scilit |
|---|---|
| Author | Qian, Xinlei Hamid, Fursham M. Sahili, Abbas El Darwis, Dina Amallia Wong, Yee Hwa Bhushan, Shashi Makeyev, Eugene V. Lescar, Julien |
| Copyright Year | 2016 |
| Description | Journal: Journal of Biological Chemistry Many eukaryotic organisms encode more than one RNA-dependent RNA polymerase (RdRP) that probably emerged as a result of gene duplication. Such RdRP paralogs often participate in distinct RNA silencing pathways and show characteristic repertoires of enzymatic activities in vitro. However, to what extent members of individual paralogous groups can undergo functional changes during speciation remains an open question. We show that orthologs of QDE-1, an RdRP component of the quelling pathway in Neurospora crassa, have rapidly diverged in evolution at the amino acid sequence level. Analyses of purified QDE-1 polymerases from N. crassa $(QDE-1^{Ncr}$) and related fungi, Thielavia terrestris $(QDE-1^{Tte}$) and Myceliophthora thermophila $(QDE-1^{Mth}$), show that all three enzymes can synthesize RNA, but the precise modes of their action differ considerably. Unlike their $QDE-1^{Ncr}$ counterpart favoring processive RNA synthesis, $QDE-1^{Tte}$ and $QDE-1^{Mth}$ produce predominantly short RNA copies via primer-independent initiation. Surprisingly, a 3.19 Å resolution crystal structure of $QDE-1^{Tte}$ reveals a quasisymmetric dimer similar to $QDE-1^{Ncr}$. Further electron microscopy analyses confirm that $QDE-1^{Tte}$ occurs as a dimer in solution and retains this status upon interaction with a template. We conclude that divergence of orthologous RdRPs can result in functional innovation while retaining overall protein fold and quaternary structure. |
| Related Links | http://www.jbc.org/content/291/17/9295.full.pdf https://core.ac.uk/reader/45323673 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4861493/pdf http://www.jbc.org/article/S0021925820411263/pdf |
| Ending Page | 9309 |
| Page Count | 15 |
| Starting Page | 9295 |
| ISSN | 00219258 |
| e-ISSN | 1083351X |
| DOI | 10.1074/jbc.m115.685933 |
| Journal | Journal of Biological Chemistry |
| Issue Number | 17 |
| Volume Number | 291 |
| Language | English |
| Publisher | Elsevier BV |
| Publisher Date | 2016-04-01 |
| Access Restriction | Open |
| Subject Keyword | Journal: Journal of Biological Chemistry Cell Biology Electron Microscopy (em) Protein Evolution Rna Interference (rnai) Rna Polymerase X-ray Crystallography Rna-dependent Rna Polymerase |
| Content Type | Text |
| Resource Type | Article |
| Subject | Cell Biology Biochemistry Molecular Biology |
