Jingchu Luo

PlantTFDB 3.0: a portal for the functional and evolutionary study of plant transcription factors

With the aim to provide a resource for functional and evolutionary study of plant transcription factors (TFs), we updated the plant TF database PlantTFDB to version 3.0 (http://planttfdb.cbi.pku.edu.cn). After refining the TF classification pipeline, we systematically identified 129 288 TFs from 83 species, of which 67 species have genome sequences, covering main lineages of green plants. Besides the abundant annotation provided in the previous version, we generated more annotations for identified TFs, including expression, regulation, interaction, conserved elements, phenotype information, expert-curated descriptions derived from UniProt, TAIR and NCBI GeneRIF, as well as references to provide clues for functional studies of TFs. To help identify evolutionary relationship among identified TFs, we assigned 69 450 TFs into 3924 orthologous groups, and constructed 9217 phylogenetic trees for TFs within the same families or same orthologous groups, respectively. In addition, we set up a TF prediction server in this version for users to identify TFs from their own sequences.

PlantTFDB 2.0: update and improvement of the comprehensive plant transcription factor database

We updated the plant transcription factor (TF) database to version 2.0 (PlantTFDB 2.0, http://planttfdb.cbi.pku.edu.cn) which contains 53 319 putative TFs predicted from 49 species. We made detailed annotation including general information, domain feature, gene ontology, expression pattern and ortholog groups, as well as cross references to various databases and literature citations for these TFs classified into 58 newly defined families with computational approach and manual inspection. Multiple sequence alignments and phylogenetic trees for each family can be shown as Weblogo pictures or downloaded as text files. We have redesigned the user interface in the new version. Users can search TFs with much more flexibility through the improved advanced search page, and the search results can be exported into various formats for further analysis. In addition, we now provide web service for advanced users to access PlantTFDB 2.0 more efficiently.

KOBAS server: a web-based platform for automated annotation and pathway identification

There is an increasing need to automatically annotate a set of genes or proteins (from genome sequencing, DNA microarray analysis or protein 2D gel experiments) using controlled vocabularies and identify the pathways involved, especially the statistically enriched pathways. We have previously demonstrated the KEGG Orthology (KO) as an effective alternative controlled vocabulary and developed a standalone KO-Based Annotation System (KOBAS). Here we report a KOBAS server with a friendly web-based user interface and enhanced functionalities. The server can support input by nucleotide or amino acid sequences or by sequence identifiers in popular databases and can annotate the input with KO terms and KEGG pathways by BLAST sequence similarity or directly ID mapping to genes with known annotations. The server can then identify both frequent and statistically enriched pathways, offering the choices of four statistical tests and the option of multiple testing correction. The server also has a ‘User Space’ in which frequent users may store and manage their data and results online. We demonstrate the usability of the server by finding statistically enriched pathways in a set of upregulated genes in Alzheimers Disease (AD) hippocampal cornu ammonis 1 (CA1). KOBAS server can be accessed at .

PlantTFDB: a comprehensive plant transcription factor database

Transcription factors (TFs) play key roles in controlling gene expression. Systematic identification and annotation of TFs, followed by construction of TF databases may serve as useful resources for studying the function and evolution of transcription factors. We developed a comprehensive plant transcription factor database PlantTFDB (http://planttfdb.cbi.pku.edu.cn), which contains 26 402 TFs predicted from 22 species, including five model organisms with available whole genome sequence and 17 plants with available EST sequences. To provide comprehensive information for those putative TFs, we made extensive annotation at both family and gene levels. A brief introduction and key references were presented for each family. Functional domain information and cross-references to various well-known public databases were available for each identified TF. In addition, we predicted putative orthologs of those TFs among the 22 species. PlantTFDB has a simple interface to allow users to search the database by IDs or free texts, to make sequence similarity search against TFs of all or individual species, and to download TF sequences for local analysis.

PlantTFDB 4.0: toward a central hub for transcription factors and regulatory interactions in plants

With the goal of providing a comprehensive, high-quality resource for both plant transcription factors (TFs) and their regulatory interactions with target genes, we upgraded plant TF database PlantTFDB to version 4.0 (http://planttfdb.cbi.pku.edu.cn/). In the new version, we identified 320 370 TFs from 165 species, presenting a more comprehensive genomic TF repertoires of green plants. Besides updating the pre-existing abundant functional and evolutionary annotation for identified TFs, we generated three new types of annotation which provide more directly clues to investigate functional mechanisms underlying: (i) a set of high-quality, non-redundant TF binding motifs derived from experiments; (ii) multiple types of regulatory elements identified from high-throughput sequencing data; (iii) regulatory interactions curated from literature and inferred by combining TF binding motifs and regulatory elements. In addition, we upgraded previous TF prediction server, and set up four novel tools for regulation prediction and functional enrichment analyses. Finally, we set up a novel companion portal PlantRegMap (http://plantregmap.cbi.pku.edu.cn) for users to access the regulation resource and analysis tools conveniently.

DRTF: a database of rice transcription factors

SUMMARY DRTF contains 2025 putative transcription factors (TFs) in Oryza sativa L. ssp. indica and 2384 in ssp. japonica, distributed in 63 families, identified by computational prediction and manual curation. It includes detailed annotations of each TF including sequence features, functional domains, Gene Ontology assignment, chromosomal localization, EST and microarray expression information, as well as multiple sequence alignment of the DNA-binding domains for each TF family. The database can be browsed and searched with a user-friendly web interface. AVAILABILITY DRTF is available at http://drtf.cbi.pku.edu.cn

SPD—a web-based secreted protein database

With the improved secreted protein prediction approach and comprehensive data sources, including Swiss-Prot, TrEMBL, RefSeq, Ensembl and CBI-Gene, we have constructed secretomes of human, mouse and rat, with a total of 18 152 secreted proteins. All the entries are ranked according to the prediction confidence. They were further annotated via a proteome annotation pipeline that we developed. We also set up a secreted protein classification pipeline and classified our predicted secreted proteins into different functional categories. To make the dataset more convincing and comprehensive, nine reference datasets are also integrated, such as the secreted proteins from the Gene Ontology Annotation (GOA) system at the European Bioinformatics Institute, and the vertebrate secreted proteins from Swiss-Prot. All these entries were grouped via a TribeMCL based clustering pipeline. We have constructed a web-based secreted protein database, which has been publicly available at http://spd.cbi.pku.edu.cn. Users can browse the database via a GO assignment or chromosomal-location-based interface. Moreover, text query and sequence similarity search are also provided, and the sequence and annotation data can be downloaded freely from the SPD website.

Genome-wide identification and evolutionary analysis of the plant specific SBP-box transcription factor family.

We made genome-wide analyses to explore the evolutionary process of the SBP-box gene family. We identified 120 SBP-box genes from nine species representing the main green plant lineages: green alga, moss, lycophyte, gymnosperm and angiosperm. A maximum-likelihood phylogenetic tree was constructed using the protein sequences of the DNA-binding domain of SBP-box genes (SBP-domain). Our results revealed that all SBP-box genes of green alga clustered into a single clade (CR group), while all genes from land-plants fell into two distinct groups. Group I had a single copy in each species except for poplar while group II had several members in each species and can be divided into several subgroups. The SBP-domain encoded by all SBP-box genes possesses two zinc fingers. The C-terminal zinc finger of both group I and group II had the same C2HC motif while their N-terminal zinc finger showed different signatures, C4 in group I and C3H in group II. The patterns of exon-intron structure in Arabidopsis and rice SBP-box genes were consistent with the phylogenetic results. A target site of microRNA miR156 was highly conserved among land-plant SBP-box genes. Our results suggested that the SBP-box gene family might have originated from a common ancestor of green plants, followed by duplication and divergence in each lineage including exon-intron loss processes.

An Annotation Update via cDNA Sequence Analysis and Comprehensive Profiling of Developmental, Hormonal or Environmental Responsiveness of the Arabidopsis AP2/EREBP Transcription Factor Gene Family

AP2/EREBP transcription factors (TFs) play functionally important roles in plant growth and development, especially in hormonal regulation and in response to environmental stress. Here we reported verification and correction of annotation through an exhaustive cDNA cloning and sequence analysis performed on 145 of 147 gene family members. A RACE analysis performed on genes with potential in-frame up-stream ATG codon resulted in identification of At2g28520 as an authentic AP2/EREBP member and corrected ORF annotations for three other members. A further phylogenetic analysis of this updated and likely complete family divided it into three major subfamilies. The expression patterns of the AP2/EREBP family members among the 11 organ or tissue types were examined using an oligo microarray and their hormonal and environmental responsiveness were further characterized using cDNA custom macroarrays. These detailed expression profile results provide strong support for a role for AP2/EREBP family members in development and in response to environmental stimuli, and a foundation for future functional analysis of this gene family.

DPTF: a database of poplar transcription factors

The database of poplar transcription factors (DPTF) is a plant transcription factor (TF) database containing 2576 putative poplar TFs distributed in 64 families. These TFs were identified from both computational prediction and manual curation. We have provided extensive annotations including sequence features, functional domains, GO assignment and expression evidence for all TFs. In addition, DPTF contains cross-links to the Arabidopsis and rice transcription factor databases making it a unique resource for genome-scale comparative studies of transcriptional regulation in model plants. Availiability: DPTF is available at http://dptf.cbi.pku.edu.cn.