TRANSFAC is a database that contains information on eukaryotic transcription factors and their DNA binding sites. It provides a relational model for storing and retrieving data on transcription factors and their regulatory sites. The database includes tables for sites, factors, class, matrices, and cells, with relationships between them. The database also includes quality parameters for DNA-protein interactions, which are based on the reliability of the experimental data. The database is accessible through ASCII flat files and a web version. It also includes cross-references to other databases such as EMBL, SwissProt, and Flybase. The database is used for the analysis of transcription factor binding sites and for the identification of regulatory elements in genes. The database is continuously updated and expanded, with future plans to integrate it with other databases and to improve its functionality. The database is freely available and can be accessed through various online resources. The database is an important resource for molecular biologists and researchers working in the field of transcriptional regulation.TRANSFAC is a database that contains information on eukaryotic transcription factors and their DNA binding sites. It provides a relational model for storing and retrieving data on transcription factors and their regulatory sites. The database includes tables for sites, factors, class, matrices, and cells, with relationships between them. The database also includes quality parameters for DNA-protein interactions, which are based on the reliability of the experimental data. The database is accessible through ASCII flat files and a web version. It also includes cross-references to other databases such as EMBL, SwissProt, and Flybase. The database is used for the analysis of transcription factor binding sites and for the identification of regulatory elements in genes. The database is continuously updated and expanded, with future plans to integrate it with other databases and to improve its functionality. The database is freely available and can be accessed through various online resources. The database is an important resource for molecular biologists and researchers working in the field of transcriptional regulation.