TFs constitute key gene regulatory components that usually participate in large multiprotein-DNA complexes, where they guide RNA polymerase (i.e. RNAP I, II and III) activity and regulate the onset and rate of RNA synthesis. The DNA-binding transcription factors (DbTFs) play a central role in specifying which genes are transcribed, as they guide the transcription machinery to distinct target genes by binding to specific gene regulatory elements located in proximal promoters as well as in distal enhancer regions. The DbTF proteins that regulate RNA Polymerase II (RNAP II) enjoy a special focus in gene regulatory network building due to their strong ability to explain the protein coding target gene specificity of transcriptional responses. Access to accurate and genome-scale knowledge concerning these DbTFs therefore is of key importance. Multiple resources with knowledge about mammalian transcription factors exist, however, we observed that
       1) most of them do not distinguish well between true DbTFs, protein-interacting TFs and general TFs and
       2) only in a minority of cases do they provide standardized evidence for the functional role of the TFs.
Because of this, users of these resources will only have an obscured view at the domain of DbTFs. In our TFcheckpoint database we present a comprehensive repository of human, mouse and rat TF candidates. All entries have been manually checked for literature information pertaining to their potential biological function as DbTFs. The database serves as a checkpoint for TF information.