HIGH-LEVELS OF PHOTOSYSTEM-I SUBUNIT-II (PSAD) MESSENGER-RNA RESULT IN THE ACCUMULATION OF THE PSAD POLYPEPTIDE ONLY IN THE PRESENCE OF LIGHT

Citation
O. Lotan et al., HIGH-LEVELS OF PHOTOSYSTEM-I SUBUNIT-II (PSAD) MESSENGER-RNA RESULT IN THE ACCUMULATION OF THE PSAD POLYPEPTIDE ONLY IN THE PRESENCE OF LIGHT, The Journal of biological chemistry, 268(22), 1993, pp. 16185-16189
Citations number
39
Categorie Soggetti
Biology
ISSN journal
00219258
Volume
268
Issue
22
Year of publication
1993
Pages
16185 - 16189
Database
ISI
SICI code
0021-9258(1993)268:22<16185:HOPS(M>2.0.ZU;2-B
Abstract
The light-regulated mRNA and polypeptide accumulation of the nuclear e ncoded subunit II (PsaD) of the photosystem I reaction center was stud ied during the greening of etiolated spinach seedlings. Upon exposure to continuous white light, the mRNA, detected at low levels in etiolat ed seedlings, accumulated in a specific pattern. In contrast, the PsaD subunit could not be detected in the etiolated seedlings; the polypep tide could first be detected in thylakoid membranes approximately 4 h after exposure to continuous light. A pulse of red light induced the e xpression of the PsaD mRNA, but the polypeptide could not be detected unless the seedlings were exposed to light. In the light (but not in t he dark), the PsaD mRNA was found associated with the polysomal fracti on. Taken together, the data suggest a dual regulatory mechanism in wh ich both the level of mRNA and the presence of light control the accum ulation of the PsaD polypeptide.