کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5511309 1539850 2017 31 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Group II introns in wheat mitochondria have degenerate structural features and varied splicing pathways
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی زیست شیمی
پیش نمایش صفحه اول مقاله
Group II introns in wheat mitochondria have degenerate structural features and varied splicing pathways
چکیده انگلیسی
Mitochondrial introns in flowering plant genes are virtually all classified as members of the group II ribozyme family although certain structural features have degenerated to varying degrees over evolutionary time. We are interested in the impact that unconventional intron architecture might have on splicing biochemistry in vivo and we have focused in particular on intronic domains V and VI, which for self-splicing introns provide a key component of the catalytic core and the bulged branchpoint adenosine, respectively. Notably, the two transesterification steps in classical group II splicing are the same as for nuclear spliceosomal introns and release the intron as a lariat. Using RT-PCR and circularized RT-PCR, we had previously demonstrated that several wheat mitochondrial introns which lack a branchpoint adenosine have atypical splicing pathways, and we have now extended this analysis to the full set of wheat introns, namely six trans-splicing and sixteen cis-splicing ones. A number of introns are excised using non-lariat pathways and interestingly, we find that several introns which do have a conventional domain VI also use pathways that appear to exploit other internal or external nucleophiles, with the lariat form being relatively minor. Somewhat surprisingly, several introns with weakly-structured domain V/VI helices still exhibit classical lariat splicing, suggesting that accessory factors aid in restoring a splicing-competent conformation. Our observations illustrate that the loss of conventional group II features during evolution is correlated with altered splicing biochemistry in an intron-distinctive manner.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: The International Journal of Biochemistry & Cell Biology - Volume 91, Part B, October 2017, Pages 156-167
نویسندگان
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