Intraplastidial trafficking of a phage-type RNA polymerase is mediated by a thylakoid RING-H2 protein

Jacinthe Azevedo; Florence Courtois; Mohamed-Ali Hakimi; Emilie Demarsy; Thierry Lagrange; Jean-Pierre Alcaraz; Pankaj Jaiswal; Laurence Maréchal-Drouard; Silva Lerbs-Mache

doi:10.1073/pnas.0800909105

Intraplastidial trafficking of a phage-type RNA polymerase is mediated by a thylakoid RING-H2 protein

Proc Natl Acad Sci U S A. 2008 Jul 1;105(26):9123-8. doi: 10.1073/pnas.0800909105. Epub 2008 Jun 20.

Authors

Jacinthe Azevedo¹, Florence Courtois, Mohamed-Ali Hakimi, Emilie Demarsy, Thierry Lagrange, Jean-Pierre Alcaraz, Pankaj Jaiswal, Laurence Maréchal-Drouard, Silva Lerbs-Mache

Affiliation

¹ Laboratoire Plastes et Differénciation Cellulaire, Université Joseph Fourier and Centre National de la Recherche Scientifique, B.P. 53, F-38041 Grenoble Cedex 9, France.

Abstract

The plastid genome of dicotyledonous plants is transcribed by three different RNA polymerases; an eubacterial-type enzyme, PEP; and two phage-type enzymes, RPOTp and RPOTmp. RPOTp plays an important role in chloroplast transcription, biogenesis, and mesophyll cell proliferation. RPOTmp fulfills a specific function in the transcription of the rrn operon in proplasts/amyloplasts during seed imbibition/germination and a more general function in chloroplasts during later developmental stages. In chloroplasts, RPOTmp is tightly associated with thylakoid membranes indicating that functional switching of RPOTmp is connected to thylakoid association. By using the yeast two-hybrid system, we have identified two proteins that interact with RPOTmp. The two proteins are very similar, both characterized by three N-terminal transmembrane domains and a C-terminal RING domain. We show that at least one of these proteins is an intrinsic thylakoid membrane protein that fixes RPOTmp on the stromal side of the thylakoid membrane, probably via the RING domain. A model is presented in which light by triggering the synthesis of the RING protein determines membrane association and functional switching of RPOTmp.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Amino Acid Sequence
Arabidopsis / enzymology*
Arabidopsis / genetics
Arabidopsis / radiation effects
Arabidopsis Proteins / chemistry
Arabidopsis Proteins / metabolism*
Bacteriophages / enzymology*
DNA-Binding Proteins
DNA-Directed RNA Polymerases / chemistry
DNA-Directed RNA Polymerases / metabolism*
Gene Expression Regulation, Plant / radiation effects
Gene Library
Intracellular Membranes / metabolism
Intracellular Membranes / radiation effects
Light
Molecular Sequence Data
Organ Specificity / radiation effects
Promoter Regions, Genetic / genetics
Protein Binding / radiation effects
Protein Transport / radiation effects
RNA, Messenger / genetics
RNA, Messenger / metabolism
RNA, Ribosomal, 16S / metabolism
Saccharomyces cerevisiae Proteins / metabolism
Thylakoids / enzymology*
Thylakoids / radiation effects
Transcription Factors / metabolism
Two-Hybrid System Techniques

Substances

Arabidopsis Proteins
DNA-Binding Proteins
GAL4 protein, S cerevisiae
RNA, Messenger
RNA, Ribosomal, 16S
Saccharomyces cerevisiae Proteins
Transcription Factors
DNA-Directed RNA Polymerases

Associated data

GENBANK/AJ400897
GENBANK/AJ400898
GENBANK/AM883105