Conserved Site

CTF transcription factor/nuclear factor 1, conserved site (IPR019739)

Short name: CTF/NFI_DNA-bd_CS


Nuclear factor I (NF-I) or CCAAT box-binding transcription factor (CTF) [PMID: 2504497, PMID: 2339052] (also known as TGGCA-binding proteins) are a family of vertebrate nuclear proteins which recognise and bind, as dimers, the palindromic DNA sequence 5'-TGGCANNNTGCCA-3'. CTF/NF-I binding sites are present in viral and cellular promoters and in the origin of DNA replication of Human adenovirus 2 (HAdV-2). The CTF/NF-I proteins were first identified as nuclear factor I, a collection of proteins that activate the replication of several Adenovirus serotypes (together with NF-II and NF-III) [PMID: 6216480]. The family of proteins was also identified as the CTF transcription factors, before the NFI and CTF families were found to be identical [PMID: 3398920]. The CTF/NF-I proteins are individually capable of activating transcription and DNA replication. In a given species, there are a large number of different CTF/NF-I proteins, generated both by alternative splicing and by the occurrence of four different genes. CTF/NF-1 proteins contain 400 to 600 amino acids. The N-terminal 200 amino-acid sequence, almost perfectly conserved in all species and genes sequenced, mediates site-specific DNA recognition, protein dimerisation and Adenovirus DNA replication. The C-terminal 100 amino acids contain the transcriptional activation domain. This activation domain is the target of gene expression regulatory pathways elicited by growth factors and it interacts with basal transcription factors and with histone H3 [PMID: 8543151].

This entry represents a specific signature for this family of proteins. The signature is a perfectly conserved, highly charged 12-residue peptide located in the DNA-binding domain of CTF/NF-I. It does not contain the four conserved Cys residues, which are required for its DNA-binding activity [PMID: 1618796].

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE patterns