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Regulation of transcriptional initiation in yeast mitochondria 总被引:3,自引:0,他引:3
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Robert G. Drager David C. Higgs Karen L. Kindle David B. Stern 《The Plant journal : for cell and molecular biology》1999,19(5):521-531
Molecular genetic studies have shown that determinants of chloroplast mRNA stability lie in both the 5' and 3' untranslated regions. While it is well-known that chloroplast mRNAs are unstable in the absence of certain nucleus-encoded factors, little is known of the decay mechanisms for chloroplast mRNA in wild-type cells. Here we used a poly(G)18 sequence, which impedes both 5'-->3' and 3'-->5' exoribonucleolytic RNA decay in vivo, to study the degradation pathway of petD mRNA in wild-type and mcd1 mutant chloroplasts of Chlamydomonas; the mcd1 mutant lacks a nucleus-encoded factor required for petD mRNA accumulation. Upon inserting poly(G) at positions -20, +25, +165 or +25/+165 relative to the mature petD 5' end, mRNAs accumulate with 5' ends corresponding to the poly(G) sequence, in addition to the normal RNA with its 5' end at +1. We interpret these results as evidence for continuous degradation of petD mRNA in wild-type cells by a 5'-->3' exoribonucleolytic activity. In the case of the -20 insertion, the accumulating RNA can be interpreted as a processing intermediate, suggesting that 5' end maturation may also involve this activity. When examined in the mcd1 mutant background, petD mRNAs with the poly(G) 5' ends, but not normal +1 ends, accumulated. However, no expression of SUIV, the petD gene product, was detected. Insertion of poly(G) at +165 in wild-type cells did not demonstrably affect SUIV accumulation, suggesting that ribosomal scanning does not occur upstream of this position. However, since neither poly(G) -20 nor +165 RNA could be translated in mcd1 cells, this raises the possibility that the MCD1 product is essential for translation. 相似文献
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Differential regulation of serum- and glucocorticoid-inducible kinase 1 (SGK1) splice variants based on alternative initiation of transcription. 总被引:1,自引:0,他引:1
Perikles Simon Michaela Schneck Tabea Hochstetter Evgenia Koutsouki Michel Mittelbronn Axel Merseburger Cora Weigert Andreas Niess Florian Lang 《Cellular physiology and biochemistry》2007,20(6):715-728