Dual functions of the nucleus-encoded factor TDA1 in trapping and translation activation of atpA transcripts in Chlamydomonas reinhardtii chloroplasts.
Plant J
; 67(6): 1055-66, 2011 Sep.
Article
en En
| MEDLINE
| ID: mdl-21623973
ABSTRACT
After endosymbiosis, organelles lost most of their initial genome. Moreover, expression of the few remaining genes became tightly controlled by the nucleus through trans-acting protein factors that are required for post-transcriptional expression (maturation/stability or translation) of a single (or a few) specific organelle target mRNA(s). Here, we characterize the nucleus-encoded TDA1 factor, which is specifically required for translation of the chloroplast atpA transcript that encodes subunit α of ATP synthase in Chlamydomonas reinhardtii. The sequence of TDA1 contains eight copies of a degenerate 38-residue motif, that we named octotrico peptide repeat (OPR), which has been previously described in a few other trans-acting factors targeted to the C. reinhardtii chloroplast. Interestingly, a proportion of the untranslated atpA transcripts are sequestered into high-density, non-polysomic, ribonucleoprotein complexes. Our results suggest that TDA1 has a dual function (i) trapping a subset of untranslated atpA transcripts into non-polysomic complexes, and (ii) translational activation of these transcripts. We discuss these results in light of our previous observation that only a proportion of atpA transcripts are translated at any given time in the chloroplast of C. reinhardtii.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Proteínas de Plantas
/
Cloroplastos
/
Chlamydomonas reinhardtii
/
ATPasas de Translocación de Protón de Cloroplastos
Idioma:
En
Revista:
Plant J
Asunto de la revista:
BIOLOGIA MOLECULAR
/
BOTANICA
Año:
2011
Tipo del documento:
Article
País de afiliación:
Francia