Solving the Riddle of the Evolution of Shine-Dalgarno Based Translation in Chloroplasts. (10th September 2019)

• Record Type: Journal Article
• Authors: Weiner, Iddo; Shahar, Noam; Marco, Pini; Yacoby, Iftach; Tuller, Tamir
• Is Part Of: Molecular biology and evolution. Volume 36:Number 12(2019)
• Page Start: 2854
• Page End: 2860
• Publication Date: 2019-09-10
• Subjects: chloroplast evolution -- Shine–Dalgarno -- mRNA translation -- Chlamydomonas reinhardtii; Molecular biology -- Periodicals; Molecular evolution -- Periodicals; Evolution, Molecular -- Periodicals; Molecular Biology -- Periodicals; 572.8
• DOI: 10.1093/molbev/msz210
• Languages: English
• ISSNs: 0737-4038

Abstract

Abstract: Chloroplasts originated from an ancient cyanobacterium and still harbor a bacterial-like genome. However, the centrality of Shine–Dalgarno ribosome binding, which predominantly regulates proteobacterial translation initiation, is significantly decreased in chloroplasts. As plastid ribosomal RNA anti-Shine–Dalgarno elements are similar to their bacterial counterparts, these sites alone cannot explain this decline. By computational simulation we show that upstream point mutations modulate the local structure of ribosomal RNA in chloroplasts, creating significantly tighter structures around the anti-Shine–Dalgarno locus, which in-turn reduce the probability of ribosome binding. To validate our model, we expressed two reporter genes (mCherry, hydrogenase) harboring a Shine–Dalgarno motif in the Chlamydomonas reinhardtii chloroplast. Coexpressing them with a 16S ribosomal RNA, modified according to our model, significantly enhances mCherry and hydrogenase expression compared with coexpression with an endogenous 16S gene.