Cytochrome f Translation in Chlamydomonas Chloroplast Is Autoregulated by its Carboxyl-Terminal DomainW⃞
AUTOR(ES)
Choquet, Yves
FONTE
American Society of Plant Biologists
RESUMO
The rate of synthesis of cytochrome f is decreased ∼10-fold when it does not assemble with the other subunits of the cytochrome b6f complex in Chlamydomonas reinhardtii chloroplasts. This assembly-mediated regulation of cytochrome f synthesis corresponds to a regulation of petA mRNA initiation of translation. Here, we demonstrate that cytochrome f translation is autoregulated by its C-terminal domain. Five cytochrome f residues conserved throughout all chloroplast genomes—residue Gln-297 in the transmembrane helix and a cluster of four amino acids, Lys-Gln-Phe-Glu, at positions 305 to 308, in the stromal extension—participate in the formation of a translation repressor motif. By contrast, positively charged residues in the stromal extension have little influence on the autoregulation process. These results do not favor a direct interaction between the repressor motif and the petA 5′ untranslated region but suggest the participation of a membrane-bound ternary effector.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=156378Documentos Relacionados
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