Identification of all the transcription factors (TFs) encoded in a given genome is a prerequisite for understanding transcriptional regulatory networks. Archaea are prokaryotes that constitute one of the three main branches of organisms with an astounding diversity of habitats. In this report, we establish the ArchaeaTF database to provide an integrated information resource about TFs in Archaea, such as basic characteristics, domain architectures, and sequence similarities against the linked databases. Through its Web interface, ArchaeaTF provides three different ways for users to retrieve the data: simple browse, keyword search, and BLAST search. Moreover, ArchaeaTF can serve as a useful platform for comparative genomics analysis of archaeal TFs since it implements a series of tools, including MUSCLE for multiple sequence alignments of the DNA-binding domains, QuickTree for phylogenetic tree construction, and OrthoMCL for ortholog identification. The released ArchaeaTF 1.0 contains 2135 putative TFs from 37 completed archaeal genomes. In conclusion, we believe that ArchaeaTF will be a useful resource and convenient platform for researchers working on TFs and transcriptional regulatory networks to retrieve information from TFs in Archaea rapidly. ArchaeaTF is accessible at http://bioinformatics.zj.cn/archaeatf.
