Thiol redox state regulates expression of psbA genes in Synechococcus sp. PCC 7942

摘要: Three psbA genes encode two different forms of the photosystem II reaction centre protein D1 in Synechococcus sp. PCC 7942. The psbAI gene encoding form I (D1:1) is mainly expressed under low growth light conditions while psbAII and psbAIII genes, (D1:2), are induced stress (e.g. high or temperature). In this paper we show that psbAII/III can be rapidly even by adding thiol reductant (DTTred) to cell culture, at a concentration does not affect photosynthetic activity. Similar induction was obtained illuminating cells with light. both instances down-regulation coincided up-regulation genes. DTTred-induced exchange transcript pools subsequently followed an D1:1 for D1:2 level. Thiol oxidants, iodosobenzoic acid diamide, reverted effects DTTred on expression. oxidants thiol-modifying agent N-ethylmaleimide also totally prevented high-light These data strongly suggest occurs mediated production reductants, whereas expression sustained more oxidizing prevail during steady-state cells.