共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
3.
4.
5.
H M Goodman J R Ecker C Dean 《Proceedings of the National Academy of Sciences of the United States of America》1995,92(24):10831-10835
Arabidopsis thaliana is a small flowering plant that is a member of the family cruciferae. It has many characteristics--diploid genetics, rapid growth cycle, relatively low repetitive DNA content, and small genome size--that recommend it as the model for a plant genome project. The current status of the genetic and physical maps, as well as efforts to sequence the genome, are presented. Examples are given of genes isolated by using map-based cloning. The importance of the Arabidopsis project for plant biology in general is discussed. 相似文献
6.
Alexandre Maréchal Jean-Sébastien Parent Félix Véronneau-Lafortune Alexandre Joyeux B. Franz Lang Normand Brisson 《Proceedings of the National Academy of Sciences of the United States of America》2009,106(34):14693-14698
Maintenance of genome stability is essential for the accurate propagation of genetic information and cell growth and survival. Organisms have therefore developed efficient strategies to prevent DNA lesions and rearrangements. Much of the information concerning these strategies has been obtained through the study of bacterial and nuclear genomes. Comparatively, little is known about how organelle genomes maintain a stable structure. Here, we report that the plastid-localized Whirly ssDNA-binding proteins are required for plastid genome stability in Arabidopsis. We show that a double KO of the genes AtWhy1 and AtWhy3 leads to the appearance of plants with variegated green/white/yellow leaves, symptomatic of nonfunctional chloroplasts. This variegation is maternally inherited, indicating defects in the plastid genome. Indeed, in all variegated lines examined, reorganized regions of plastid DNA are amplified as circular and/or head-tail concatemers. All amplified regions are delimited by short direct repeats of 10–18 bp, strongly suggesting that these regions result from illegitimate recombination between repeated sequences. This type of recombination occurs frequently in plants lacking both Whirlies, to a lesser extent in single KO plants and rarely in WT individuals. Maize mutants for the ZmWhy1 Whirly protein also show an increase in the frequency of illegitimate recombination. We propose a model where Whirlies contribute to plastid genome stability by protecting against illegitimate repeat-mediated recombination. 相似文献
7.
8.
9.
Mingguang Lei Honggui La Kun Lu Pengcheng Wang Daisuke Miki Zhizhong Ren Cheng-Guo Duan Xingang Wang Kai Tang Liang Zeng Lan Yang Heng Zhang Wenfeng Nie Pan Liu Jianping Zhou Renyi Liu Yingli Zhong Dong Liu Jian-Kang Zhu 《Proceedings of the National Academy of Sciences of the United States of America》2014,111(1):527-532
10.
Distribution of genes in the genome of Arabidopsis thaliana and its implications for the genome organization of plants 总被引:2,自引:0,他引:2 下载免费PDF全文
Abdelali Barakat Giorgio Matassi Giorgio Bernardi 《Proceedings of the National Academy of Sciences of the United States of America》1998,95(17):10044-10049
Previous work has shown that, in the large genomes of three Gramineae [rice, maize, and barley: 415, 2,500, and 5,300 megabases (Mb), respectively] most genes are clustered in long DNA segments (collectively called the “gene space”) that represent a small fraction (12–24%) of nuclear DNA, cover a very narrow (0.8–1.6%) GC range, and are separated by vast expanses of gene-empty sequences. In the present work, we have analyzed the small (ca. 120 Mb) nuclear genome of Arabidopsis thaliana and shown that its organization is drastically different from that of the genomes of Gramineae. Indeed, (i) genes are distributed over about 85% of the main band of DNA in CsCl and cover an 8% GC range; (ii) ORFs are fairly evenly distributed in long (>50 kb) sequences from GenBank that amount to about 10 Mb; and (iii) the GC levels of protein-coding sequences (and of their third codon positions) are correlated with the GC levels of their flanking sequences. The different pattern of gene distribution of Arabidopsis compared with Gramineae appears to be because the genomes of the latter comprise (i) many large gene-empty regions separating gene clusters and (ii) abundant transposons in the intergenic sequences of gene clusters. Both sequences are absent or very scarce in the Arabidopsis genome. These observations provide a comparative view of angiosperm genome organization. 相似文献
11.
Genome organization in dicots: genome duplication in Arabidopsis and synteny between soybean and Arabidopsis 总被引:6,自引:0,他引:6 下载免费PDF全文
Grant D Cregan P Shoemaker RC 《Proceedings of the National Academy of Sciences of the United States of America》2000,97(8):4168-4173
Synteny between soybean and Arabidopsis was studied by using conceptual translations of DNA sequences from loci that map to soybean linkage groups A2, J, and L. Synteny was found between these linkage groups and all four of the Arabidopsis chromosomes, where GenBank contained enough sequence for synteny to be identified confidently. Soybean linkage group A2 (soyA2) and Arabidopsis chromosome I showed significant synteny over almost their entire lengths, with only 2-3 chromosomal rearrangements required to bring the maps into substantial agreement. Smaller blocks of synteny were identified between soyA2 and Arabidopsis chromosomes IV and V (near the RPP5 and RPP8 genes) and between soyA2 and Arabidopsis chromosomes I and V (near the PhyA and PhyC genes). These subchromosomal syntenic regions were themselves homeologous, suggesting that Arabidopsis has undergone a number of segmental duplications or possibly a complete genome duplication during its evolution. Homologies between the homeologous soybean linkage groups J and L and Arabidopsis chromosomes II and IV also revealed evidence of segmental duplication in Arabidopsis. Further support for this hypothesis was provided by the observation of very close linkage in Arabidopsis of homologs of soybean Vsp27 and Bng181 (three locations) and purple acid phosphatase-like sequences and homologs of soybean A256 (five locations). Simulations show that the synteny and duplications we report are unlikely to have arisen by chance during our analysis of the homology reports. 相似文献
12.
Flores M Morales L Gonzaga-Jauregui C Domínguez-Vidaña R Zepeda C Yañez O Gutiérrez M Lemus T Valle D Avila MC Blanco D Medina-Ruiz S Meza K Ayala E García D Bustos P González V Girard L Tusie-Luna T Dávila G Palacios R 《Proceedings of the National Academy of Sciences of the United States of America》2007,104(15):6099-6106
Several lines of evidence suggest that reiterated sequences in the human genome are targets for nonallelic homologous recombination (NAHR), which facilitates genomic rearrangements. We have used a PCR-based approach to identify breakpoint regions of rearranged structures in the human genome. In particular, we have identified intrachromosomal identical repeats that are located in reverse orientation, which may lead to chromosomal inversions. A bioinformatic workflow pathway to select appropriate regions for analysis was developed. Three such regions overlapping with known human genes, located on chromosomes 3, 15, and 19, were analyzed. The relative proportion of wild-type to rearranged structures was determined in DNA samples from blood obtained from different, unrelated individuals. The results obtained indicate that recurrent genomic rearrangements occur at relatively high frequency in somatic cells. Interestingly, the rearrangements studied were significantly more abundant in adults than in newborn individuals, suggesting that such DNA rearrangements might start to appear during embryogenesis or fetal life and continue to accumulate after birth. The relevance of our results in regard to human genomic variation is discussed. 相似文献
13.
14.
Manolis Kellis Barbara Wold Michael P. Snyder Bradley E. Bernstein Anshul Kundaje Georgi K. Marinov Lucas D. Ward Ewan Birney Gregory E. Crawford Job Dekker Ian Dunham Laura L. Elnitski Peggy J. Farnham Elise A. Feingold Mark Gerstein Morgan C. Giddings David M. Gilbert Thomas R. Gingeras Eric D. Green Roderic Guigo Tim Hubbard Jim Kent Jason D. Lieb Richard M. Myers Michael J. Pazin Bing Ren John A. Stamatoyannopoulos Zhiping Weng Kevin P. White Ross C. Hardison 《Proceedings of the National Academy of Sciences of the United States of America》2014,111(17):6131-6138
15.
Beaujean N Taylor JE McGarry M Gardner JO Wilmut I Loi P Ptak G Galli C Lazzari G Bird A Young LE Meehan RR 《Proceedings of the National Academy of Sciences of the United States of America》2004,101(20):7636-7640
In contrast to mice, in sheep no genome-wide demethylation of the paternal genome occurs within the first postfertilization cell cycle. This difference could be due either to an absence of a sheep demethylase activity that is present in mouse ooplasm or to an increased protection of methylated cytosine residues in sheep sperm. Here, we use interspecies intracytoplasmic sperm injection to demonstrate that sheep sperm DNA can be demethylated in mouse oocytes. Surprisingly, mouse sperm can also be demethylated to a limited extent in sheep oocytes. Our results suggest that the murine demethylation process is facilitated either by a sperm-derived factor or by male pronuclear chromatin composition. 相似文献
16.
Active tissue-specific DNA demethylation conferred by somatic cell nuclei in stable heterokaryons 总被引:1,自引:0,他引:1
Zhang F Pomerantz JH Sen G Palermo AT Blau HM 《Proceedings of the National Academy of Sciences of the United States of America》2007,104(11):4395-4400
DNA methylation is among the most stable epigenetic marks, ensuring tissue-specific gene expression in a heritable manner throughout development. Here we report that differentiated mesodermal somatic cells can confer tissue-specific changes in DNA methylation on epidermal progenitor cells after fusion in stable multinucleate heterokaryons. Myogenic factors alter regulatory regions of genes in keratinocyte cell nuclei, demethylating and activating a muscle-specific gene and methylating and silencing a keratinocyte-specific gene. Because these changes occur in the absence of DNA replication or cell division, they are mediated by an active mechanism. Thus, the capacity to transfer epigenetic changes to other nuclei is not limited to embryonic stem cells and oocytes but is also a property of highly specialized mammalian somatic cells. These results suggest the possibility of directing the reprogramming of readily available postnatal human progenitor cells toward specific tissue cell types. 相似文献
17.
Integration of bovine leukemia proviral DNA in the genome of infected cells was investigated in cattle affected by either the persistent lymphocytosis or the lymph node tumor form of enzootic bovine leukosis. In persistent lymphocytosis, proviral DNA was found to be integrated at a large number of genomic sites in one-fourth to one-third of circulating leucocytes. In the lymph node tumor form, in contrast, proviral DNA was found to be integrated at one or very few sites in the genomes of a larger fraction of both circulating leucocytes and lymph node tumor cells. 相似文献
18.
19.
20.
Stem cells are defined as cells that have the ability to perpetuate themselves through self-renewal and to generate functional mature cells by differentiation. During each stage, coordinated gene expression is crucial to maintain the balance between self-renewal and differentiation. Disturbance of this accurately balanced system can lead to a variety of malignant disorders. In mammals, DNA cytosine-5 methylation is a well-studied epigenetic pathway that is catalyzed by DNA methyltransferases and is implicated in the control of balanced gene expression, but also in hematological malignancies. In this review, we focus on the TET (ten-eleven-translocation) genes, which recently were identified to catalyze the conversion of cytosine-5 methylation to 5-hydroxymethyl-cytosine, an intermediate form potentially involved in demethylation. In addition, members of the TET family are playing a role in ES cell maintenance and inner cell mass cell specification and were demonstrated to be involved in hematological malignancies. Recently, a correlation between low genomic 5-hydroxymethyl-cytosine and TET2 mutation status was shown in patients with myeloid malignancies. 相似文献