Search

Poaceae (the grasses) includes rice, maize, wheat, and other crops, and is the most economically important angiosperm family. Poaceae is also one of the largest plant families, consisting of over 11 000 species with a global distribution that contributes to diverse ecosystems. Poaceae species are classified into 12 subfamilies, with generally strong phylogenetic support for their monophyly. However, many relationships within subfamilies, among tribes and/or subtribes, remain uncertain. To better resolve the Poaceae phylogeny, we generated 342 transcriptomic and seven genomic datasets; these were combined with other genomic and transcriptomic datasets to provide sequences for 357 Poaceae species in 231 genera, representing 45 tribes and all 12 subfamilies. Over 1200 low-copy nuclear genes were retrieved from these datasets, with several subsets obtained using additional criteria, and used for coalescent analyses to reconstruct a Poaceae phylogeny. Our results strongly support the monophyly of 11 subfamilies; however, the subfamily Puelioideae was separated into two non-sister clades, one for each of the two previously defined tribes, supporting a hypothesis that places each tribe in a separate subfamily. Molecular clock analyses estimated the crown age of Poaceae to be ∼101 million years old. Ancestral character reconstruction of C 3 /C 4 photosynthesis supports the hypothesis of multiple independent origins of C 4 photosynthesis. These origins are further supported by phylogenetic analysis of the ppc gene family that encodes the phosphoenolpyruvate carboxylase, which suggests that members of three paralogous subclades (ppc - aL1a , ppc - aL1b , and ppc - B2) were recruited as functional C 4 ppc genes. This study provides valuable resources and a robust phylogenetic framework for evolutionary analyses of the grass family. The grass family is economically and ecologically important and contains thousands of species capable of C 4 photosynthesis, but uncertain relationships remain in its phylogeny. In this work, the authors use nuclear genes from >350 grasses to generate a highly supported phylogeny that provides a reference for estimating the origins of the family and its major subgroups. Statistical and molecular evolutionary analyses support multiple origins of C 4 photosynthesis in grasses. [ABSTRACT FROM AUTHOR]

PRMT5 is an essential arginine methyltransferase and a therapeutic target in MTAP-null cancers. PRMT5 uses adaptor proteins for substrate recruitment through a previously undefined mechanism. Here, we identify an evolutionarily conserved peptide sequence shared among the three known substrate adaptors (CLNS1A, RIOK1, and COPR5) and show that it is necessary and sufficient for interaction with PRMT5. We demonstrate that PRMT5 uses modular adaptor proteins containing a common binding motif for substrate recruitment, comparable with other enzyme classes such as kinases and E3 ligases. We structurally resolve the interface with PRMT5 and show via genetic perturbation that it is required for methylation of adaptor-recruited substrates including the spliceosome, histones, and ribosomal complexes. Furthermore, disruption of this site affects Sm spliceosome activity, leading to intron retention. Genetic disruption of the PRMT5-substrate adaptor interface impairs growth of MTAP-null tumor cells and is thus a site for development of therapeutic inhibitors of PRMT5., Competing Interests: Declaration of interests Materials related to this article are in a provisional patent application by the Broad Institute. W.R.S. is a board or scientific advisory board (SAB) member and holds equity in Peloton Therapeutics, Ideaya Biosciences, Civetta Therapeutics, and Bluebird bio; has consulted for Array, Astex, Dynamo Therapeutics, Ipsen, Merck Pharmaceuticals, PearlRiver Therapeutics, Sanofi, Scorpion Therapeutics, and Servier; and receives research funding from Pfizer Pharmaceuticals, Merck Pharmaceuticals, Ideaya Biosciences, and Deerfield Management. B.J.M. is an employee and equity holder of Tango Therapeutics. D. Porter is an employee and equity holder of Cedilla Therapeutics. A.J.A. has consulted for Oncorus Inc., Arrakis Therapeutics, and Merck & Company and has research funding from Mirati Therapeutics and Deerfield Management., (Copyright © 2021 Elsevier Inc. All rights reserved.)