CI protein
Encyclopedia
cI protein also known as the lambda repressor, is the sole protein expressed in the lysogenic state of Lambda phage
. cI turns off transcription
at the phage's L and R promoters as well as any other invading lambda phages into the host cell. It is a transcription factor
and contains the common helix-turn-helix
DNA binding domain.
Lambda phage
Enterobacteria phage λ is a temperate bacteriophage that infects Escherichia coli.Lambda phage is a virus particle consisting of a head, containing double-stranded linear DNA as its genetic material, and a tail that can have tail fibers. The phage particle recognizes and binds to its host, E...
. cI turns off transcription
Transcription (genetics)
Transcription is the process of creating a complementary RNA copy of a sequence of DNA. Both RNA and DNA are nucleic acids, which use base pairs of nucleotides as a complementary language that can be converted back and forth from DNA to RNA by the action of the correct enzymes...
at the phage's L and R promoters as well as any other invading lambda phages into the host cell. It is a transcription factor
Transcription factor
In molecular biology and genetics, a transcription factor is a protein that binds to specific DNA sequences, thereby controlling the flow of genetic information from DNA to mRNA...
and contains the common helix-turn-helix
Helix-turn-helix
In proteins, the helix-turn-helix is a major structural motif capable of binding DNA. It is composed of two α helices joined by a short strand of amino acids and is found in many proteins that regulate gene expression...
DNA binding domain.