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Title: REDUCED CHLOROPLAST COVERAGE genes from Arabidopsis thaliana help to establish the size of the chloroplast compartment

Eukaryotic cells require mechanisms to establish the proportion of cellular volume devoted to particular organelles. These mechanisms are poorly understood. From a screen for plastid-to-nucleus signaling mutants in Arabidopsis thaliana, we cloned a mutant allele of a gene that encodes a protein of unknown function that is homologous to two other Arabidopsis genes of unknown function and Arabidopsis. In contrast to FRIENDLY, these three homologs of FRIENDLY are found only in photosynthetic organisms. Based on these data, we proposed that FRIENDLY expanded into a small gene family to help regulate the energy metabolism of cells that contain both mitochondria and chloroplasts. Indeed, we found that knocking out these genes caused a number of chloroplast phenotypes, including a reduction in the proportion of cellular volume devoted to chloroplasts to 50% of wild type. Thus, we refer to these genes as REDUCED CHLOROPLAST COVERAGE (REC). The size of the chloroplast compartment was reduced most in rec1 mutants. The REC1 protein accumulated in the cytosol and the nucleus. REC1 was excluded from the nucleus when plants were treated with amitrole, which inhibits cell expansion and chloroplast function. Finally, we conclude that REC1 is an extraplastidic protein that helps to establish the size ofmore » the chloroplast compartment, and that signals derived from cell expansion or chloroplasts may regulate REC1.« less
Authors:
 [1] ;  [1] ;  [2] ;  [3] ;  [4] ;  [1] ;  [1] ;  [1]
  1. Michigan State Univ., East Lansing, MI (United States)
  2. Michigan State Univ., East Lansing, MI (United States); Eidgenossische Technische Hochschule (ETH), Zurich (Switzerland)
  3. Michigan State Univ., East Lansing, MI (United States); Univ. of Pennsylvania, Philadelphia, PA (United States)
  4. Michigan State Univ., East Lansing, MI (United States); Wayne State Univ., Detroit, MI (United States)
Publication Date:
OSTI Identifier:
1237516
Grant/Contract Number:
FG02-91ER20021; FG02-06ER15808; NNX12AN71G; MCB-1121943; MCB1243792; IOB 0517841; IOS 1021755
Type:
Published Article
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 113; Journal Issue: 8; Journal ID: ISSN 0027-8424
Publisher:
National Academy of Sciences, Washington, DC (United States)
Research Org:
Michigan State Univ., East Lansing, MI (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; Arabidopsis; chlorophyll; chloroplast; chloroplast coverage; plastid signaling