Extra-ribosomal function(s) of the plastid ribosomal protein L4 in the expression of ribosomal components in spinach
Extra-ribosomal function(s) of the plastid ribosomal protein L4 in the expression of ribosomal components in spinach
复制标题
质体核糖体蛋白 L4 在菠菜核糖体成分表达中的核糖体外功能
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
S. Lerbs
中科院分区：
文献类型：
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作者：
Y. Trifa;S. Lerbs
我们之前已经鉴定了与菠菜核编码的质体核糖体蛋白L4对应的cDNA。L4蛋白属于核糖体蛋白组，其核糖体外功能已在原核生物中得到证实。一般来说，这些功能与核糖体成分的表达有关。为了分析质体L4蛋白是否也可能具有核糖体外功能，我们制备了质体L4蛋白作为硫氧还蛋白融合蛋白，并分析了其在原核（大肠杆菌）和质体系统中的作用。我们发现，通过稳定nusa依赖性反应中停滞的转录复合物，质体L4蛋白可以取代大肠杆菌L4蛋白，对大肠杆菌S10操纵子进行nusa依赖性的衰减控制。在质体中，L4蛋白抑制rrn操纵子的转录。因此，我们的研究结果表明，质体L4蛋白在核糖体成分的表达中具有核糖体外功能。
Abstract We have previously characterised the cDNA corresponding to the nucleus-encoded, plastid ribosomal protein L4 from spinach. The L4 protein belongs to the group of ribosomal proteins for which extra-ribosomal functions have been demonstrated in prokaryotes. In general, these functions are concerned with the expression of ribosomal components. In order to analyse whether the plastid L4 protein might also have (an) extra-ribosomal function(s) we have produced the plastid L4 protein as a thioredoxin fusion protein and analysed its role in both prokaryotic (E. coli) and plastid systems. We found that the plastid L4 protein can replace the E. coli L4 protein in the NusA-dependent attenuation control of the E. coli S10 operon by stabilising stalled transcription complexes in a NusA-dependent reaction. In plastids, the L4 protein inhibits transcription of the rrn operon. Our results thus suggest extra-ribosomal function(s) for the plastid L4 protein in the expression of ribosomal components.