A conserved inverted repeat from rice plastome functions as an intrinsic transcription terminator
- 23 Downloads
Results from a previous rice transcription mapping and the GeSTer algorithm analysis used in this in-vestigation for rice plastid genome suggest that an inverted repeat, IRsl8, in 3′ region of the plastid rps18 gene may serve as a transcription terminator. The in vitro transcription assay showed that the transcript ending at the IRsl8 was not proc-essed by ribonucleases but terminated intrinsically in an rNTP substrate-dependent manner as demonstrated for the first time in plant gene regulation. For the poly-T tract (TTCTTTTTT) 3′-proximal to the IRsl8, the C base conver-sion to T resulting in a perfect 9 Ts can dramatically increase termination efficiency, which is a common feature of bacte-rial intrinsic termination. This study is the first case to indi-cate that a conserved inverted repeat with a poly-T tract from higher plant chloroplast contributes to transcription termination of the translation-associated rps18 gene in a manner with the intrinsic termination, probably resulting from a heritage of endosymbiosis.
Keywordsintrinsic transcription termination inverted repeatkw]rice chloroplast rps18
Unable to display preview. Download preview PDF.
- 7.Drager, R. G., Zeidler, M., Simpson, C. L. et al., A chloroplast transcript lacking the 3′ inverted repeat is degraded by 3′− >5′ exo-ribonuclease activity, RNA, 1996, 2(7): 652–663.Google Scholar
- 11.Chen, L. J., Quantifying termination of transcription by spinach chloroplast RNA polymerase using supercoiled templates contain-ing tandem copies of the thra terminator, Bot. Bull. Acad. Sin., 1995, 36: 95–100.Google Scholar
- 13.Gruissem, W., Zurawski, G., Analysis of promoter regions for the spinach chloroplast rbcL, atpB and psbA genes, EMBO J., 1985, 4: 3375–3383.Google Scholar