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Accumulation of D1 polypeptide in tobacco plastids is regulated via the untranslated region of the psbA mRNA.
Author(s) -
Staub J.M.,
Maliga P.
Publication year - 1993
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1993.tb05692.x
Subject(s) - biology , plastid , messenger rna , untranslated region , gene , nicotiana tabacum , microbiology and biotechnology , au rich element , gene expression , translational efficiency , chimeric gene , translation (biology) , etiolation , chloroplast , genetics , biochemistry , enzyme
The plastid psbA mRNA is present in all tissues, while the encoded 32 kDa D1 protein of photosystem II accumulates tissue‐specifically and in response to light. To study the regulation of D1 accumulation, a chimeric uidA gene encoding beta‐glucuronidase (GUS) under control of the psbA 5′‐ and 3′‐regulatory regions (224 and 393 bp, respectively), was integrated into the tobacco plastid genome. A high level of GUS accumulation in leaves and the lack of GUS in roots, with uidA mRNA present in both tissues, indicated tissue‐specific accumulation of the chimeric gene product. Light‐regulated accumulation of GUS in seedlings was shown. (i) Light‐induced accumulation (100‐fold) of GUS in etiolated cotyledons was accompanied by only a modest increase in mRNA levels. (ii) Inhibition of GUS synthesis was observed in cotyledons when light‐grown seedlings were transferred to the dark, with no reduction in mRNA levels. Tissue‐specific and light‐regulated accumulation of GUS indicates that D1 accumulation is controlled via cis‐acting regulatory elements in the untranslated region of the psbA mRNA. We propose that in tobacco, control of translation initiation is the primary mechanism regulating D1 protein accumulation.