title: PLANEX: the plant co-expression database.
abstract: BACKGROUND
  The PLAnt co-EXpression database (PLANEX) is a new internet-based database for plant gene analysis. PLANEX (http://planex.plantbioinformatics.org) contains publicly available GeneChip data obtained from the Gene Expression Omnibus (GEO) of the National Center for Biotechnology Information (NCBI). PLANEX is a genome-wide co-expression database, which allows for the functional identification of genes from a wide variety of experimental designs. It can be used for the characterization of genes for functional identification and analysis of a gene's dependency among other genes. Gene co-expression databases have been developed for other species, but gene co-expression information for plants is currently limited.
  
  
  METHODS
  We constructed PLANEX as a list of co-expressed genes and functional annotations for Arabidopsis thaliana, Glycine max, Hordeum vulgare, Oryza sativa, Solanum lycopersicum, Triticum aestivum, Vitis vinifera and Zea mays. PLANEX reports Pearson's correlation coefficients (PCCs; r-values) that distribute from a gene of interest for a given microarray platform set corresponding to a particular organism. To support PCCs, PLANEX performs an enrichment test of Gene Ontology terms and Cohen's Kappa value to compare functional similarity for all genes in the co-expression database. PLANEX draws a cluster network with co-expressed genes, which is estimated using the k-mean method. To construct PLANEX, a variety of datasets were interpreted by the IBM supercomputer Advanced Interactive eXecutive (AIX) in a supercomputing center.
  
  
  CONCLUSIONS
  PLANEX provides a correlation database, a cluster network and an interpretation of enrichment test results for eight plant species. A typical co-expressed gene generates lists of co-expression data that contain hundreds of genes of interest for enrichment analysis. Also, co-expressed genes can be identified and cataloged in terms of comparative genomics by using the 'Co-expression gene compare' feature. This type of analysis will help interpret experimental data and determine whether there is a common term among genes of interest.
authors.affiliation: Department of Plant Biotechnology, Dongguk Univ-Seoul, Seoul 100-715, Korea.
authors.forename: Won Cheol
authors.initials: WC
authors.lastname: Yim
authors.forename: Yongbin
authors.initials: Y
authors.lastname: Yu
authors.forename: Kitae
authors.initials: K
authors.lastname: Song
authors.forename: Cheol Seong
authors.initials: CS
authors.lastname: Jang
authors.forename: Byung-Moo
authors.initials: BM
authors.lastname: Lee
mesh_terms: D030561:Databases, Nucleic Acid; D017343:Genes, Plant; D020407:Internet; D010940:Plant Proteins / Q000235:genetics*; D010944:Plants / Q000235:genetics*
chemical_list: D010940:Plant Proteins