Locus-specific paramutation in Zea mays is maintained by a PICKLE-like chromodomain helicase DNA-binding 3 protein controlling development and male gametophyte function

PLoS Genet. 2020 Dec 15;16(12):e1009243. doi: 10.1371/journal.pgen.1009243. eCollection 2020 Dec.

Abstract

Paramutations represent directed and meiotically-heritable changes in gene regulation leading to apparent violations of Mendelian inheritance. Although the mechanism and evolutionary importance of paramutation behaviors remain largely unknown, genetic screens in maize (Zea mays) identify five components affecting 24 nucleotide RNA biogenesis as required to maintain repression of a paramutant purple plant1 (pl1) allele. Currently, the RNA polymerase IV largest subunit represents the only component also specifying proper development. Here we identify a chromodomain helicase DNA-binding 3 (CHD3) protein orthologous to Arabidopsis (Arabidopsis thaliana) PICKLE as another component maintaining both pl1 paramutation and normal somatic development but without affecting overall small RNA biogenesis. In addition, genetic tests show this protein contributes to proper male gametophyte function. The similar mutant phenotypes documented in Arabidopsis and maize implicate some evolutionarily-conserved gene regulation while developmental defects associated with the two paramutation mutants are largely distinct. Our results show that a CHD3 protein responsible for normal plant ontogeny and sperm transmission also helps maintain meiotically-heritable epigenetic regulatory variation for specific alleles. This finding implicates an intersection of RNA polymerase IV function and nucleosome positioning in the paramutation process.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Alleles
  • Arabidopsis Proteins / genetics
  • Chromatin Assembly and Disassembly / genetics*
  • DNA Helicases / genetics
  • DNA Helicases / metabolism*
  • DNA-Directed RNA Polymerases / genetics
  • DNA-Directed RNA Polymerases / metabolism
  • Epigenesis, Genetic
  • Gene Expression Regulation, Plant
  • Genotype
  • Mutation
  • Phenotype
  • Phylogeny
  • Plant Proteins / genetics
  • Plant Proteins / metabolism*
  • Pollen / genetics
  • Pollen / metabolism*
  • RNA, Plant / genetics
  • RNA, Small Untranslated / genetics
  • RNA, Small Untranslated / metabolism
  • Zea mays / genetics*
  • Zea mays / growth & development
  • Zea mays / metabolism

Substances

  • Arabidopsis Proteins
  • Plant Proteins
  • RNA, Plant
  • RNA, Small Untranslated
  • DNA-Directed RNA Polymerases
  • AT2G25170 protein, Arabidopsis
  • DNA Helicases