Knock-out of the Mg protoporphyrin IX methyltransferase gene in Arabidopsis: Effects on chloroplast development and on chloroplast-to-nucleus signaling. - Archive ouverte HAL Access content directly
Journal Articles Journal of Biological Chemistry Year : 2007

Knock-out of the Mg protoporphyrin IX methyltransferase gene in Arabidopsis: Effects on chloroplast development and on chloroplast-to-nucleus signaling.

Abstract

Protoporphyrin IX is the last common intermediate between the haem and chlorophyll biosynthesis pathways. The addition of Mg directs this molecule toward chlorophyll biosynthesis. The first step downstream from the branchpoint is catalyzed by the Mg chelatase and is a highly regulated process. The corresponding product, Mg protoporphyrin IX, has been proposed to play an important role as a signaling molecule implicated in plastid-to-nucleus communication. In order to get more information on the chlorophyll biosynthesis pathway and on Mg protoporphyrin IX derivative functions, we have identified an Mg protoporphyrin IX methyltransferase (CHLM) knock-out mutant in Arabidopsis in which the mutation induces a blockage downstream from Mg protoporphyrin IX and an accumulation of this chlorophyll biosynthesis intermediate. Our results demonstrate that the CHLM gene is essential for the formation of chlorophyll and subsequently for the formation of photosystems I and II and cyt b6f complexes. Analysis of gene expression in the chlm mutant provides an independent indication that Mg protoporphyrin IX is a negative effector of nuclear photosynthetic gene expression, as previously reported. Moreover, it suggests the possible implication of Mg protoporphyrin IX methylester, the product of CHLM, in chloroplast-to-nucleus signaling. Finally, post-transcriptional up-regulation of the level of the CHLH subunit of the Mg chelatase has been detected in the chlm mutant and most likely corresponds to specific accumulation of this protein inside plastids. This result suggests that the CHLH subunit might play an important regulatory role when the chlorophyll biosynthetic pathway is disrupted at this particular step.
Fichier principal
Vignette du fichier
pontier_et_al_pour_HAL.pdf (869.23 Ko) Télécharger le fichier
Origin : Files produced by the author(s)
Loading...

Dates and versions

hal-00125007 , version 1 (22-01-2007)

Licence

Copyright

Identifiers

Cite

Dominique Pontier, Catherine Albrieux, Jacques Joyard, Thierry Lagrange, Maryse Block. Knock-out of the Mg protoporphyrin IX methyltransferase gene in Arabidopsis: Effects on chloroplast development and on chloroplast-to-nucleus signaling.. Journal of Biological Chemistry, 2007, 282 (4), pp.2297-2304. ⟨10.1074/jbc.M610286200⟩. ⟨hal-00125007⟩
1388 View
343 Download

Altmetric

Share

Gmail Facebook X LinkedIn More