DCL is a plant-specific protein required for plastid ribosomal RNA processing and embryo development

Plant Mol Biol. 2003 Nov;53(4):531-43. doi: 10.1023/B:PLAN.0000019061.79773.06.

Abstract

The defective chloroplast and leaf-mutable (dcl-m) mutation of tomato blocks chloroplast differentiation in leaf mesophyll cells and a signaling system that appears to be required for morphogenesis of palisade cells during leaf growth. To dissect the function of DCL, mutants with stable dcl alleles (dcl-s) were generated and examined for their phenotype. DCL/dcl-s plant produce dcl-s/dcl-s seeds with embryos arrested at the globular stage of development. The levels of several chloroplast- and nuclear-encoded proteins are strongly reduced in dcl-m mutant leaf sectors without significant changes in their corresponding mRNAs. The 4.5S rRNA fails to be processed efficiently, however, suggesting that DCL has a direct or indirect function in rRNA processing or correct ribosome assembly. Accordingly, chloroplasts in dcl-m sectors are impaired in polysome assembly, which can explain the reduced accumulation of chloroplast-encoded proteins. These results suggest that DCL is required for chloroplast rRNA processing, and emphasize the importance of plastid function during embryogenesis.

MeSH terms

  • Amino Acid Sequence
  • Cell Nucleus / genetics
  • Chloroplasts / metabolism
  • Lycopersicon esculentum / genetics*
  • Lycopersicon esculentum / growth & development
  • Lycopersicon esculentum / metabolism
  • Molecular Sequence Data
  • Mutation
  • Plant Proteins / genetics
  • Plant Proteins / metabolism*
  • Polyribosomes / metabolism
  • RNA, Chloroplast / metabolism*
  • RNA, Plant / genetics
  • RNA, Plant / metabolism
  • RNA, Ribosomal / metabolism*
  • Seeds / genetics
  • Seeds / growth & development*
  • Sequence Homology, Amino Acid
  • Time Factors
  • Transcription, Genetic / genetics

Substances

  • DCL protein, Lycopersicon esculentum
  • Plant Proteins
  • RNA, Chloroplast
  • RNA, Plant
  • RNA, Ribosomal