Structural analysis of Arabidopsis thaliana chromosome 5. X. Sequence features of the regions of 3,076,755 bp covered by sixty P1 and TAC clones.

In our ongoing project to deduce the nucleotide sequence of Arabidopsis thaliana chromosome 5, non-redundant P1 and TAC clones have been sequenced on the basis of the fine physical map, and as of January, 2000, the sequences of 16.6 Mb representing approximately 60% of chromosome 5 have been accumulated and released at our web site. Along with the sequence determination, structural features of the sequenced regions have been analyzed by applying a variety of computer programs, and we already predicted a total of 2697 potential protein coding genes in the 11,166,130 bp regions, which are covered by 159 P1 and TAC clones. In this paper, we describe the structural features of the 3,076,755 bp regions covered by newly analyzed 60 P1 and TAC clones. A total of 715 potential protein coding genes were identified, giving an average density of the genes identified of 1 gene per 4001 bp. Introns were observed in 80% of the genes, and the average number per gene and the average length of the introns were 4.5 and 147 bp, respectively. These sequence features are nearly identical to those in our latest report in which the data were compiled based on a new standard of gene assignment including the computer-predicted hypothetical genes. The regions also contained 12 tRNA genes when searched by similarity to reported tRNA genes and the tRNA scan-SE program. The sequence data and information on the potential genes are available through the World Wide Web database KAOS (Kazusa Arabidopsis data Opening Site) at http://www.kazusa.or.jp/kaos/.     

Structural analysis of Arabidopsis thaliana chromosome 3. I. Sequence features of the regions of 4,504,864 bp covered by sixty P1 and TAC clones.

Based on the physical map of Arabidopsis thaliana chromosome 3 previously constructed with CIC YAC, TAC, P1 and BAC clones (Sato, S. et al., DNA Res., 5, 163-168, 1998), a total of 60 P1 and TAC clones were sequenced, and the sequence features of the resulting 4,504,864 bp regions were analyzed by applying various computer programs for similarity search and gene modeling. As a result, a total of 1054 potential protein-coding genes were identified. The average density of the genes identified was 1 gene per 4066 bp. Introns were observed in 77% of the genes, and the average number per gene and the average length of the introns were 3.9 and 156 bp, respectively. These sequence features are essentially identical to those of chromosome 5 in our previous reports, but the gene density was slightly higher than that observed for chromosomes 2 and 4. The regions also contained 10 tRNA genes when searched by similarity to reported tRNA genes and the tRNA scan-SE program. The sequence data and information on the potential genes are available through the World Wide Web database KAOS (Kazusa Arabidopsis data Opening Site) at http://www.kazusa.or.jp/kaos/.     

Structural analysis of Arabidopsis thaliana chromosome 3. II. Sequence features of the 4,251,695 bp regions covered by 90 P1, TAC and BAC clones.

To deduce the entire sequence of the top arm of the Arabidopsis thaliana chromosome 3, the sequence determination was performed on a total of 90 P1, TAC and BAC clones chosen according to our sequencing strategy. Sequence features of the resulting 4,251,695 bp regions were analyzed with various computer programs for similarity search and gene modeling. As a result, a total of 941 potential protein-coding genes were identified. The average density of the genes identified was 1 gene per 4210 bp. Introns were observed in 73% of the genes, and the average number per gene and the average length of the introns were 3.6 and 159 bp, respectively. These sequence features are essentially identical to those of chromosomes 3 and 5 in our previous reports. The regions also contained 14 tRNA genes when searched by similarity to reported tRNA genes and the tRNA scan-SE program. The sequence data and information on the potential genes are available through the World Wide Web database KAOS (Kazusa Arabidopsis data Opening Site) at http://www.kazusa.or.jp/kaos/.     

Structural Analysis ofArabidopsis thaliana Chromosome 5. VI. Sequence Features of the Regions of 1,367,185 bp Covered by 19 Physically Assigned P1 and TAC Clones

Nineteen Pl and TAC clones, which have been mapped on the finephysical map of the Arabidopsis thaliana chromosome 5, weresequenced according to the shotgun-based strategy, and theirstructural features were analysed. The total length of the regionssequenced in this study was 1,367,185 bp. Combining this withthe regions covered by 90 P1 and TAC clones proviously reported,the total length of chromosome 5 sequenced to date becomes 8,058,855bp. On the basis of similarity search against protein and ESTdatabases and gene modeling with computer programs, a totalof 330 potential protein-coding regions were identified, bringingan average density of the genes to approximately one gene per4.1 kb. Introns were identified in 81.0% of the potential proteingenes for which the entire gene structure was predicted, withan average number per gene of 4.2 and an average length of theintrons of 180 bp. The RNA-coding genes identified were 9 tRNAgenes corresponding to 8 amino acid species and 2 genes forU2 nuclear RNA. These sequence features are essentially identicalto those in the previously reported sequences. The sequencedata and gene information are available on the World Wide Webdatabase KAOS (Kazusa Arabidopsis data Opening Site) at http://www.kazusa.or.jp/arabi/.     

Structural analysis of Arabidopsis thaliana chromosome 5. VIII. Sequence features of the regions of 1,081,958 bp covered by seventeen physically assigned P1 and TAC clones.

A total of 17 Pl and TAC clones each representing an assigned region of chromosome 5 were isolated from P1 and TAC genomic libraries of Arabidopsis thaliana Columbia, and their nucleotide sequences were determined. The length of the clones sequenced in this study summed up to 1,081,958 bp. As we have previously reported the sequence of 9,072,622 bp by analysis of 125 P1 and TAC clones, the total length of the sequences of chromosome 5 determined so far is now 10,154,580 bp. The sequences were subjected to similarity search against protein and EST databases and analysis with computer programs for gene modeling. As a consequence, a total of 253 potential protein-coding genes with known or predicted functions were identified. The positions of exons which do not show apparent similarity to known genes were also assigned using computer programs for exon prediction. The average density of the genes identified in this study was 1 gene per 4277 bp. Introns were observed in 74% of the potential protein genes, and the average number per gene and the average length of the introns were 4.3 and 168 bp, respectively. The sequence data and gene information are available on the World Wide Web database KAOS (Kazusa Arabidopsis data Opening Site) at http://www.kazusa.or.jp/arabi/.     

Structural Analysis of Arabidopsis thaliana Chromosome 5. VII. Sequence Features of the Regions of 1,013,767 bp Covered by Sixteen Physically assigned P1 and TAC Clones

Sixteen Pl and TAC clones assigned to Arabidopsis thaliana chromosome5 were sequenced, and their sequence features were analyzedusing various computer programs. The total length of the sequencesdetermined was 1,013,767 bp. Together with the nucleotide sequencesof 109 clones previously reported, the regions of chromosome5 sequenced so far now total 9,072,622 bp, which presumablycovers approximately one-third of the chromosome. A similaritysearch against the reported gene sequences predicted the presenceof a total of 225 protein-coding genes and/or gene segmentsin the newly sequenced regions, indicating an average gene densityof one gene per 4.5 kb. Introns were identified in 72.4% ofthe potential protein genes for which the entire gene structurewas predicted, and the average number per gene and the averagelength of the introns were 3.3 and 163 bp, respectively. Thesesequence features are essentially identical to those in thepreviously reported sequences. The sequence data and gene informationare available on the World Wide Web database KAOS (Kazusa Arabidopsisdata Opening Site) at http://www.kazusa.or.jp/arabi/.     

Structural analysis of a Lotus japonicus genome. II. Sequence features and mapping of sixty-five TAC clones which cover the 6.5-mb regions of the genome.

Sixty-five TAC (transformation-competent artificial chromosomes) clones were selected from a genomic library of Lotus japonicus accession MG-20 based on the sequence information of expressed sequences tags (ESTs), cDNA and gene information, and their nucleotide sequences were determined. The average insert size of the TAC clone was approximately 100 kb, and the total length of the sequenced regions in this study is 6,556,100 bp. Together with the nucleotide sequences of 56 TAC clones previously reported, the regions sequenced so far total 12,029,295 bp. By comparison with the sequences in protein and EST databases and by analysis with computer programs for gene modeling, a total of 711 potential protein-encoding genes with known or predicted functions, 239 gene segments and 90 pseudogenes were identified in the newly sequenced regions. The average gene density assigned so far was 1 gene/9140 bp. The average length of the assigned genes was 2.6 kb, which is considerably larger than that assigned in the Arabidopsis thaliana genome (1.9 kb for 6451 genes). Introns were identified in approximately 73% of the potential genes, and the average number and length of the introns per gene were 3.4 and 377 bp, respectively. Simple sequence repeat length polymorphism (SSLP) or derived cleaved amplified polymorphic sequence (dCAPS) markers were generated based on the nucleotide sequences of the genomic clones obtained, and each clone was mapped onto the linkage map using the F2 mapping population derived from a cross of two accessions of L. japonicus, Gifu B-129 and Miyakojima MG-20. The sequence data, gene information and mapping information are available through the World Wide Web at http://www.kazusa.or.jp/lotus/.     

Structural analysis of a Lotus japonicus genome. III. Sequence features and mapping of sixty-two TAC clones which cover the 6.7 Mb regions of the genome.

A total of sixty-two clones were selected from a TAC (transformation-competent artificial chromosome) genomic library of the Lotus japonicus accession MG-20 based on the sequence information of expressed sequence tags (ESTs), cDNA and gene information, and their nucleotide sequences were determined. The length of the sequenced regions in this study is 6,682,189 bp, and the total length of the regions sequenced so far is 18,711,484 bp together with the nucleotide sequences of 121 TAC clones previously reported. By comparison with the sequences in protein and EST databases and analysis with computer programs for gene modeling, a total of 573 potential protein-coding genes with known or predicted functions, 91 gene segments and 272 pseudogenes were identified in the newly sequenced regions. Each of the sequenced clones was localized onto the linkage map of two accessions of L. japonicus, Gifu B-129 and Miyakojima MG-20, using simple sequence repeat length polymorphism (SSLP) or derived cleaved amplified polymorphic sequence (dCAPS) markers generated based on the nucleotide sequences of the clones. The sequence data, gene information and mapping information are available through the World Wide Web at http://www.kazusa.or.jp/lotus/.     

Structural analysis of a Lotus japonicus genome. I. Sequence features and mapping of fifty-six TAC clones which cover the 5.4 mb regions of the genome.

A total of 56 TAC clones with an average insert size of 100 kb were isolated from a TAC library of the Lotus japonicus genome based on the expressed sequences tags (ESTs), cDNA and gene information, and their nucleotide sequences were determined according to the shot-gun based strategy. The total length of the sequenced regions is 5,473,195 bp. By comparison with the sequences in protein and EST databases and analysis with computer programs for gene modeling, a total of 605 potential protein-encoding genes with known or predicted functions, 69 gene segments, and 172 pseudogenes were identified. The average density of the genes assigned so far is 1 gene/8120 bp. Introns were identified in approximately 78% of the potential genes. There was an average of 3.8 introns per gene and the average length of the introns was 375 bp. DNA markers were generated based on the nucleotide sequences obtained, and each clone was mapped onto the linkage map using the F2 mapping population derived from a cross of L. japonicus Gifu B-129 and Miyakojima MG-20. The sequence data, gene information and mapping information are available through the World Wide Web at http://www.kazusa.or.jp/lotus/.     

Structural analysis of a Lotus japonicus genome. V. Sequence features and mapping of sixty-four TAC clones which cover the 6.4 mb regions of the genome.

We determined the nucleotide sequences of 64 TAC (transformation-competent artificial chromosome) clones selected from genomic libraries of Lotus japonicus accession Miyakojima MG-20 based on the sequence information of expressed sequence tags (ESTs), cDNAs, genes and DNA markers from L. japonicus and other legumes. The length of the DNA regions sequenced in this study was 6,370,255 bp, and the total length of the L. japonicus genome sequenced so far is 32,537,698 bp together with the nucleotide sequences of 256 TAC clones previously reported. Five hundred forty-eight potential protein-encoding genes with known or predicted functions, 127 gene segments and 224 pseudogenes were assigned to the newly sequenced regions by computer prediction and similarity searches against the sequences in protein and EST databases. Based on the nucleotide sequences of the clones, simple sequence repeat length polymorphism (SSLP) or derived cleaved amplified polymorphic sequence (dCAPS) markers were generated, and each clone was genetically localized onto the linkage map of two accessions of L. japonicus, MG-20 and Gifu B-129. The sequence data, gene information and mapping information are available through the World Wide Web at http://www.kazusa.or.jp/lotus/.     

Structural analysis of a Lotus japonicus genome. IV. Sequence features and mapping of seventy-three TAC clones which cover the 7.5 mb regions of the genome.

Using the sequence information of expressed sequences tags (ESTs), cDNAs and genes from Lotus japonicus and other legumes, 73 TAC (transformation-competent artificial chromosomes) clones were selected from a genomic library of L. japonicus accession MG-20, and their nucleotide sequences were determined. The length of the DNA sequenced in this study was 7,455,959 bp, and the total length of the DNA regions sequenced so far is 26,167,443 bp together with the nucleotide sequences of 183 TAC clones previously reported. By similarity searches against the sequences in protein and EST databases and prediction by computer programs, a total of 699 potential protein-encoding genes with known or predicted functions, 163 gene segments and 267 pseudogenes were assigned to the newly sequenced regions. Based oil the nucleotide sequences of the clones, simple sequence repeat length polymorphism (SSLP) or derived cleaved amplified polymorphic sequence (dCAPS) markers were generated, and each clone was located onto the linkage map of two accessions of L. japonicus, Gifu B-129 and Miyakojima MG-20. The sequence data, gene information and mapping information are available through the World Wide Web at http://www.kazusa.or.jp/lotus/.     

A sequence-ready contig map of the top arm of Arabidopsis thaliana chromosome 3.

A fine physical map of the top arm of Arabidopsis thaliana chromosome 3 has been constructed by ordering P1, TAC and BAC clones using the sequences of a variety of DNA markers and end-sequences of clones. The marker sequences used in this study were derived from 58 DNA markers, 93 YAC end-sequences, and 807 end-sequences of P1, TAC and BAC clones. The entire top arm of chromosome 3, except for the centromeric and telomeric regions, was covered by a single contig 13.3 Mb long. This fine physical map will facilitate gene isolation by map-based cloning experiments as well as genome sequencing of the top arm of chromosome 3. The map and end-sequence information are available on the web site KAOS (Kazusa Arabidopsis data Opening Site) at [http://www.kazusa.or.jp/arabi/].     

Complete genomic sequence of the filamentous nitrogen-fixing cyanobacterium Anabaena sp. strain PCC 7120.

The nucleotide sequence of the entire genome of a filamentous cyanobacterium, Anabaena sp. strain PCC 7120, was determined. The genome of Anabaena consisted of a single chromosome (6,413,771 bp) and six plasmids, designated pCC7120alpha (408,101 bp), pCC7120beta (186,614 bp), pCC7120gamma (101,965 bp), pCC7120delta (55,414 bp), pCC7120epsilon (40,340 bp), and pCC7120zeta (5,584 bp). The chromosome bears 5368 potential protein-encoding genes, four sets of rRNA genes, 48 tRNA genes representing 42 tRNA species, and 4 genes for small structural RNAs. The predicted products of 45% of the potential protein-encoding genes showed sequence similarity to known and predicted proteins of known function, and 27% to translated products of hypothetical genes. The remaining 28% lacked significant similarity to genes for known and predicted proteins in the public DNA databases. More than 60 genes involved in various processes of heterocyst formation and nitrogen fixation were assigned to the chromosome based on their similarity to the reported genes. One hundred and ninety-five genes coding for components of two-component signal transduction systems, nearly 2.5 times as many as those in Synechocystis sp. PCC 6803, were identified on the chromosome. Only 37% of the Anabaena genes showed significant sequence similarity to those of Synechocystis, indicating a high degree of divergence of the gene information between the two cyanobacterial strains.     

小麦—簇毛表6VS／6AL易位系可转化人工染色体（TAC）文库的构建

可转化人工染色体（Ｔｒａｎｓｆｏｒｍａｔｉｏｎ ｃｏｍｐｅｔｅｎｔ Ａｒｔｉｆｉｃｉａｌ Ｃｈｒｏｍｏｓｏｍｅ,ＴＡＣ）是具有克隆和转移大片段基因能力的新型载体,是植被基因克隆和转化的有效工具。为了克隆泪科抗白粉病基因和其它基因,本研究用ＴＣＡ载体ｐＹＬＴＡＣ１７构建了带有抗白粉病基因Ｐｍ２１的小麦＝簇毛麦６ＶＳ／６ＡＬ易位系的基因组ＤＮＡ文库。该文库包含２１０万个克隆平均插入征段３５ｌｂ,相当于