共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
3.
Sigal Cohen Michal Zmudjak Catherine Colas des Francs‐Small Sunita Malik Felix Shaya Ido Keren Eduard Belausov Yair Many Gregory G. Brown Ian Small Oren Ostersetzer‐Biran 《The Plant journal : for cell and molecular biology》2014,78(2):253-268
Group II introns are large catalytic RNAs that are found in bacteria and organellar genomes of lower eukaryotes, but are particularly prevalent within mitochondria in plants, where they are present in many critical genes. The excision of plant mitochondrial introns is essential for respiratory functions, and is facilitated in vivo by various protein cofactors. Typical group II introns are classified as mobile genetic elements, consisting of the self‐splicing ribozyme and its own intron‐encoded maturase protein. A hallmark of maturases is that they are intron‐specific, acting as cofactors that bind their intron‐containing pre‐RNAs to facilitate splicing. However, the degeneracy of the mitochondrial introns in plants and the absence of cognate intron‐encoded maturase open reading frames suggest that their splicing in vivo is assisted by ‘trans’‐acting protein factors. Interestingly, angiosperms harbor several nuclear‐encoded maturase‐related (nMat) genes that contain N‐terminal mitochondrial localization signals. Recently, we established the roles of two of these paralogs in Arabidopsis, nMAT1 and nMAT2, in the splicing of mitochondrial introns. Here we show that nMAT4 (At1g74350) is required for RNA processing and maturation of nad1 introns 1, 3 and 4 in Arabidopsis mitochondria. Seed germination, seedling establishment and development are strongly affected in homozygous nmat4 mutants, which also show modified respiration phenotypes that are tightly associated with complex I defects. 相似文献
4.
5.
6.
In this paper we investigate the relationships among intron density (number of introns per kilobase of coding sequence), gene
expression level, and strength of splicing signals in two species: Drosophila melanogaster and Caenorhabditis elegans. We report a negative correlation between intron density and gene expression levels, opposite to the effect previously observed
in human. An increase in splice site strength has been observed in long introns in D. melanogaster. We show this is also true of C. elegans. We also examine the relationship between intron density and splice site strength. There is an increase in splice site strength
as the intron structure becomes less dense. This could suggest that introns are not recognized in isolation but could function
in a cooperative manner to ensure proper splicing. This effect remains if we control for the effects of alternative splicing
on splice site strength.
Reviewing Editor: Dr. Nicolas Galtier 相似文献
7.
8.
The pentatricopeptide repeat protein EMPTY PERICARP8 is required for the splicing of three mitochondrial introns and seed development in maize
下载免费PDF全文
![点击此处可从《The Plant journal : for cell and molecular biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Feng Sun Xiaoyan Zhang Yun Shen Hongchun Wang Rui Liu Xiaomin Wang Dahai Gao Yan‐Zhuo Yang Yiwei Liu Bao‐Cai Tan 《The Plant journal : for cell and molecular biology》2018,95(5):919-932
9.
10.
11.
Recent studies have demonstrated that transposable elements in maize and Drosophila are spliced from pre-mRNA. These transposable element introns represent the first examples of recent addition of introns into nuclear genes. The eight reported examples of transposable element splicing include members of the maize Ac/Ds and Spm/dSpm and the Drosophila P and 412 element families. The details of the splicing of these transposable elements and their relevance to models of intron origin are discussed. 相似文献
12.
M.K. Tan 《Journal of molecular evolution》1997,44(6):637-645
Studies of the distribution of the three group I introns (intron A, intron T, and intron AT) in the 26S rDNA of Gaeumannomyces graminis had suggested that they were transferred to a common ancestor of G. graminis var. avenae and var. tritici after it had branched off from var. graminis. Intron AT and intron A exhibited vertical inheritance and coevolved in concert with their hosts. Intron loss could occur
after its acquisition. Loss of any one of the three introns could occur in var. tritici whereas only loss of intron T had been found in the majority of var. avenae isolates. The existence of isolates of var. tritici and var. avenae with three introns suggested that intron loss could be reversed by intron acquisition and that the whole process is a dynamic
one. This process of intron acquisition and intron loss reached different equilibrium points for different varieties and subgroups,
which explained the irregular distribution of these introns in G. graminis. Each of the three group I introns was more closely related to other intron sequences that share the same insertion point
in the 26S rDNA than to each other. These introns in distantly related organisms appeared to have a common ancestry. This
system had provided a good model for studies on both the lateral transfer and common ancestry of group I introns in the 26S
rRNA genes.
Received: 17 May 1996 / Accepted: 14 January 1997 相似文献
13.
14.
15.
Ido Keren Ayenachew Bezawork-Geleta Max Kolton Inbar Maayan Eduard Belausov Maggie Levy Anahit Mett David Gidoni Felix Shaya Oren Ostersetzer-Biran 《RNA (New York, N.Y.)》2009,15(12):2299-2311
Mitochondria (mt) in plants house about 20 group-II introns, which lie within protein-coding genes required in both organellar genome expression and respiration activities. While in nonplant systems the splicing of group-II introns is mediated by proteins encoded within the introns themselves (known as “maturases”), only a single maturase ORF (matR) has retained in the mitochondrial genomes in plants; however, its putative role(s) in the splicing of organellar introns is yet to be established. Clues to other proteins are scarce, but these are likely encoded within the nucleus as there are no obvious candidates among the remaining ORFs within the mtDNA. Intriguingly, higher plants genomes contain four maturase-related genes, which exist in the nucleus as self-standing ORFs, out of the context of their evolutionary-related group-II introns “hosts.” These are all predicted to reside within mitochondria and may therefore act “in-trans” in the splicing of organellar-encoded introns. Here, we analyzed the intracellular locations of the four nuclear-encoded maturases in Arabidopsis and established the roles of one of these genes, At5g46920 (AtnMat2), in the splicing of several mitochondrial introns, including the single intron within cox2, nad1 intron2, and nad7 intron2. 相似文献
16.
Simpson CG Jennings SN Clark GP Thow G Brown JW 《The Plant journal : for cell and molecular biology》2004,37(1):82-91
In potato invertase genes, the constitutively included, 9-nucleotide (nt)-long mini-exon requires a strong branchpoint and U-rich polypyrimidine tract for inclusion. The strength of these splicing signals was demonstrated by greatly enhanced splicing of a poorly spliced intron and by their ability to support splicing of an artificial mini-exon, following their introduction. Plant introns also require a second splicing signal, UA-rich intronic elements, for efficient intron splicing. Mutation of the branchpoint caused loss of mini-exon inclusion without loss of splicing enhancement, showing that the same U-rich sequence can function as either a polypyrimidine tract or a UA-rich intronic element. The distinction between the splicing signals depended on intron context (the presence or absence of an upstream, adjacent and functional branchpoint), and on the sequence context of the U-rich elements. Polypyrimidine tracts tolerated C residues while UA-rich intronic elements tolerated As. Thus, in plant introns, U-rich splicing elements can have dual roles as either a general plant U-rich splicing signal or a polypyrimidine tract. Finally, overexpression of two different U-rich binding proteins enhanced intron recognition significantly. These results highlight the importance of co-operation between splicing signals, the importance of other nucleotides within U-rich elements for optimal binding of competing splicing factors and effects on splicing efficiency of U-rich binding proteins. 相似文献
17.
18.
19.
Intron-specific stimulation of anaerobic gene expression and splicing efficiency in maize cells 总被引:6,自引:0,他引:6
U. Köhler R. Cerff R. Hehl M. Donath R. R. Mendel 《Molecular & general genetics : MGG》1996,251(2):252-258
Most of the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) genes characterized in plants and algae to date have one intron very close to the 5 end of the gene. To study the functional relevance of some of these introns for gene expression we have analysed the influence of three 5 introns on transient gene expression of the anaerobically inducible maizeGapC4 promoter in maize cells. Under aerobic conditions, reporter gene expression is increased in the presence of the first introns of theGapC4 andGapC1 genes, and the first intron of the nuclear encoded chloroplast-specificGapA1 gene. In contrast, theGapC4 intron increases anaerobic gene expression above the level obtained for the intronless construct, while anaerobic expression of constructs harboring theGapA1 andGapC1 introns was similar to the anaerobic expression level of the intronless construct. Splicing analysis revealed that theGapC4 intron is processed more efficiently under anaerobic conditions, while no change in splicing efficiency is observed for theGapC1 and theGapA1 introns when subjected to anaerobic conditions. These results suggest that an increase in splicing efficiency contributes to the anaerobic induction of the maizeGapC4 gene. 相似文献
20.
Base composition is not uniform across the genome of Drosophila melanogaster. Earlier analyses have suggested that there is variation in composition in D. melanogaster on both a large scale and a much smaller, within-gene, scale. Here we present analyses on 117 genes which have reliable intron/exon
boundaries and no known alternative splicing. We detect significant heterogeneity in G+C content among intron segments from
the same gene, as well as a significant positive correlation between the intron and the third codon position G+C content within
genes. Both of these observations appear to be due, in part, to an overall decline in intron and third codon position G+C
content along Drosophila genes with introns. However, there is also evidence of an increase in third codon position G+C content at the start of genes;
this is particularly evident in genes without introns. This is consistent with selection acting against preferred codons at
the start of genes.
Received: 24 February 1997 / Accepted: 10 November 1997 相似文献