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Step‐wise and lineage‐specific diversification of plant RNA polymerase genes and origin of the largest plant‐specific subunits
Author(s) -
Wang Yaqiong,
Ma Hong
Publication year - 2015
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.13432
Subject(s) - biology , gene duplication , gene , genetics , lineage (genetic) , protein subunit , functional divergence , phylogenetic tree , rna polymerase , plant evolution , rna polymerase ii , evolutionary biology , rna , genome , gene family , gene expression , promoter
Summary Proteins often function as complexes, yet little is known about the evolution of dissimilar subunits of complexes. DNA ‐directed RNA polymerases ( RNAP s) are multisubunit complexes, with distinct eukaryotic types for different classes of transcripts. In addition to Pol I– III , common in eukaryotes, plants have Pol IV and V for epigenetic regulation. Some RNAP subunits are specific to one type, whereas other subunits are shared by multiple types. We have conducted extensive phylogenetic and sequence analyses, and have placed RNAP gene duplication events in land plant history, thereby reconstructing the subunit compositions of the novel RNAP s during land plant evolution. We found that Pol IV /V have experienced step‐wise duplication and diversification of various subunits, with increasingly distinctive subunit compositions. Also, lineage‐specific duplications have further increased RNAP complexity with distinct copies in different plant families and varying divergence for subunits of different RNAP s. Further, the largest subunits of Pol IV /V probably originated from a gene fusion in the ancestral land plants. We propose a framework of plant RNAP evolution, providing an excellent model for protein complex evolution.