着重从以下几个方面比较系统地论述了目前对植物光合基因 psb A 的研究进展:1.独具的功能;2.在叶绿体基因组中的定位及拷贝数;3.密码子使用特性;4.表达调控特点,包括转录、转录后、翻译、翻译后4个水平的调控特点以及光等因素对调控的介...着重从以下几个方面比较系统地论述了目前对植物光合基因 psb A 的研究进展:1.独具的功能;2.在叶绿体基因组中的定位及拷贝数;3.密码子使用特性;4.表达调控特点,包括转录、转录后、翻译、翻译后4个水平的调控特点以及光等因素对调控的介导;5.编码产物 D_1蛋白的光抑制现象,并对尚待深入研究的主要问题作了阐述. 光合基因:psb A;展开更多
The chloroplast psbA gene coding for Q_B of the photosystem Ⅱ reaction center in higher plants is an important light-regulated gene, and the promoter region controlling the efficiency of its expression is in the upst...The chloroplast psbA gene coding for Q_B of the photosystem Ⅱ reaction center in higher plants is an important light-regulated gene, and the promoter region controlling the efficiency of its expression is in the upstream region from the 5’-ending. The promoter structure of this gene resembles those E. coli, having a "-10" box and a "-35" box, but between these two boxes, a consensus sequence resembling eukaryotic "TATA" box has been found recently in some plants.展开更多
Oryza sativa L. ssp. japonica and indica exhibit different sensitivity to photoinhibition and they show different stability of their core proteins D1 in the chloroplast photosystem Ⅱ. Using in situ hybridization, psb...Oryza sativa L. ssp. japonica and indica exhibit different sensitivity to photoinhibition and they show different stability of their core proteins D1 in the chloroplast photosystem Ⅱ. Using in situ hybridization, psbA, the gene encoding D1 protein of O. sativa ssp. japonica cv. 9516, and that of O. sativa ssp. indica cv. Shanyou 63 was cloned. As revealed by homology comparison of their sequences, the sequences are identical in the regions of promoter and 5′-UTR; differences are found in individual bases in the coding region all of which, being in the third position of respective codons, however, do not affect the amino acids coded finally; a difference is noted in the length of the oligo-U sequence in the region of 3′-UTR. It is thus apparent that, rather than a result of any difference in the amino acid sequences, the differences in the sensitivity to photoinhibition of D1 proteins between japonica and indica rice may be related to the upstream factors that regulate expression of psbA or to differences of photoprotective mechanisms.展开更多
The 2.2 kb EcoRI fragment containing the chloroplast pshA gene from millet (Setaria italica) has been cloned and the nucleotide sequence of the 5’-noncoding region has been determined. The 5’-flanking region is foun...The 2.2 kb EcoRI fragment containing the chloroplast pshA gene from millet (Setaria italica) has been cloned and the nucleotide sequence of the 5’-noncoding region has been determined. The 5’-flanking region is found to contain prokaryote-like promoter structures: compared with prokaryotic promoters, the“-35”box (TTGACA) shows 100% homology while, in the ‘-10’box (TATACT), one different nucleotide is found. In addition, between these two boxes, there is a consensus sequence“TATATA”.just as in prokaryotic promoters. All these results indicate that millet psbA promoter has both prokaryotic and eukaryotic characteristies. The mRNA leader region of millet pshA gene is 87 bp, the same length as sorghum. However, an additional CTATTT sequence is found as compared with rice and an additional TTTT, as with wheat, barley and rye. So the differences between C3 and C4 plants may be universal in the family of Gramineae. Furthermore, computer analysis shows that a small stem-loop structure might be formed in pshA mRNA leader region in these six plants. The above-mentioned additional CTATTT sequence happens to be just located within the stem-loop structure, thus leading to different sizes of the stem-loops among these six species. It is likely that this small secondary structure may have some effect on the expression and regulation of the psbA gene.展开更多
To study the relationship between the structures of rice and sorghum psbA 3 UTR and gene expres-sional activity, six chimeric luc genes that encode luciferase under control of rice or sorghum psbA 5 UTR and 3’UTR or ...To study the relationship between the structures of rice and sorghum psbA 3 UTR and gene expres-sional activity, six chimeric luc genes that encode luciferase under control of rice or sorghum psbA 5 UTR and 3’UTR or only 5 UTR were constructed. The levels of LUC accumulation in E . coli and the transcript stability in soluble pro-tein extracts of rice, sorghum chloroplast and E. coli were examined respectively, and a detailed analysis about the function of these two 3’UTR has been carried out. Here the regulation effect of these 3’UTR are reported: ( i ) When having the same promoter, the chimeric genes with rice 3 UTR produce LUC much more than that with sorghum 3 UTR; ( ii ) elimination of 3 UTR results in the fluctuation of LUC accumulation no matter whether it is under control of rice or sorghum psbA 5’UTR; ( Hi ) rice psbA 3’UTR exhibits a greater effect on stabilizing tran-scripts; ( IV ) psbA 3’lR-RNAs are more stable in chloroplast protein extracts than in E. coli protein extracts.展开更多
基金This work was supported by the grant from the Chinese National High-Tech Project
文摘The chloroplast psbA gene coding for Q_B of the photosystem Ⅱ reaction center in higher plants is an important light-regulated gene, and the promoter region controlling the efficiency of its expression is in the upstream region from the 5’-ending. The promoter structure of this gene resembles those E. coli, having a "-10" box and a "-35" box, but between these two boxes, a consensus sequence resembling eukaryotic "TATA" box has been found recently in some plants.
文摘Oryza sativa L. ssp. japonica and indica exhibit different sensitivity to photoinhibition and they show different stability of their core proteins D1 in the chloroplast photosystem Ⅱ. Using in situ hybridization, psbA, the gene encoding D1 protein of O. sativa ssp. japonica cv. 9516, and that of O. sativa ssp. indica cv. Shanyou 63 was cloned. As revealed by homology comparison of their sequences, the sequences are identical in the regions of promoter and 5′-UTR; differences are found in individual bases in the coding region all of which, being in the third position of respective codons, however, do not affect the amino acids coded finally; a difference is noted in the length of the oligo-U sequence in the region of 3′-UTR. It is thus apparent that, rather than a result of any difference in the amino acid sequences, the differences in the sensitivity to photoinhibition of D1 proteins between japonica and indica rice may be related to the upstream factors that regulate expression of psbA or to differences of photoprotective mechanisms.
文摘The 2.2 kb EcoRI fragment containing the chloroplast pshA gene from millet (Setaria italica) has been cloned and the nucleotide sequence of the 5’-noncoding region has been determined. The 5’-flanking region is found to contain prokaryote-like promoter structures: compared with prokaryotic promoters, the“-35”box (TTGACA) shows 100% homology while, in the ‘-10’box (TATACT), one different nucleotide is found. In addition, between these two boxes, there is a consensus sequence“TATATA”.just as in prokaryotic promoters. All these results indicate that millet psbA promoter has both prokaryotic and eukaryotic characteristies. The mRNA leader region of millet pshA gene is 87 bp, the same length as sorghum. However, an additional CTATTT sequence is found as compared with rice and an additional TTTT, as with wheat, barley and rye. So the differences between C3 and C4 plants may be universal in the family of Gramineae. Furthermore, computer analysis shows that a small stem-loop structure might be formed in pshA mRNA leader region in these six plants. The above-mentioned additional CTATTT sequence happens to be just located within the stem-loop structure, thus leading to different sizes of the stem-loops among these six species. It is likely that this small secondary structure may have some effect on the expression and regulation of the psbA gene.
基金Project supported by the Chinese National High-Tech Project.
文摘To study the relationship between the structures of rice and sorghum psbA 3 UTR and gene expres-sional activity, six chimeric luc genes that encode luciferase under control of rice or sorghum psbA 5 UTR and 3’UTR or only 5 UTR were constructed. The levels of LUC accumulation in E . coli and the transcript stability in soluble pro-tein extracts of rice, sorghum chloroplast and E. coli were examined respectively, and a detailed analysis about the function of these two 3’UTR has been carried out. Here the regulation effect of these 3’UTR are reported: ( i ) When having the same promoter, the chimeric genes with rice 3 UTR produce LUC much more than that with sorghum 3 UTR; ( ii ) elimination of 3 UTR results in the fluctuation of LUC accumulation no matter whether it is under control of rice or sorghum psbA 5’UTR; ( Hi ) rice psbA 3’UTR exhibits a greater effect on stabilizing tran-scripts; ( IV ) psbA 3’lR-RNAs are more stable in chloroplast protein extracts than in E. coli protein extracts.
