Does the lambda repressor bind to DNA?
Both Cro and λ-repressor can bind with high affinity to a large number of DNA sites that are not used as natural operators.
Which DNA-binding motif does lambda repressor have?
The DNA-binding motif utilized by Lambda Repressor is a Helix-Turn-Helix (Beamer and Pabo, 1992).
What does the lambda repressor do?
The lambda repressor is a self assembling dimer also known as the cI protein. It binds DNA in the helix-turn-helix binding motif. It regulates the transcription of the cI protein and the Cro protein. The life cycle of lambda phages is controlled by cI and Cro proteins.
What are the three domains found on most transcription factor dimers?
It is composed of three domains: high-mobility group box (HMG box), dimerization (DIM) and transactivation (TAD). One of the main processes for regulation and variability of the pathways involving Sox9 is the self-gene expression regulation of Sox9.
How does lambda repressor and Cro work?
Cro, a repressor protein of temperate bacteriophages (e.g. lambda [l], 434, P22), works in opposition to the phage’s repressor to control the genetic switch that determines whether a lytic or lysogenic cycle will follow infection.
Is lambda repressor a dimer?
lambda repressor is a dimer at physiological concentrations, but forms tetramers and octamers at a hundredfold higher concentration. We predict that two lambda repressor dimers form a tetramer in vitro when bound to two lambda operators spaced 24 bp apart and that two such tetramers interact to form an octamer.
What are lambda phage vectors?
Bacteriophages such as lambda phages can also be used as effective vectors for transferring recombinant DNA molecules into cells for cloning. A lambda phage is a bacteriophage that infects E. Coli cells. This phage, like any virus, readily undergoes two types of life cycles – the lytic cycle and the lysogenic cycle.
What do DNA binding domains do?
The function of DNA binding is either structural or involves transcription regulation, with the two roles sometimes overlapping. DNA-binding domains with functions involving DNA structure have biological roles in DNA replication, repair, storage, and modification, such as methylation.
What are the transcription factor domains?
Figure 12.1. Structure of a prototypical transcription factor (TF). An inducible TF usually displays four different structural domains: a DNA binding domain (mandatory), a transactivation domain (mandatory), a dimerization domain, and a ligand binding site.
How does Cro bind to DNA?
The cro protein binds to the same three sites in the right operator (OR) of bacteriophage lambda DNA as does the lambda repressor. Dimethyl sulfate protection experiments reveal major groove contacts for both proteins, and cro protein protects from methylation a subset of those purines protected by lambda repressor.
Is lambda Cro a transcription factor?
Bacteriophage lambda encodes two repressors: the Cro repressor that acts to turn off early gene transcription during the lytic cycle, and the lambda or cI repressor required to maintain lysogenic growth.
What is lambda phage DNA?
Lambda DNA, a linear, double-stranded phage DNA containing 12 bp single-stranded complementary 5′-ends, is derived from an Escherichia coli bacteriophage (Bacteriophage lambda cI857 Sam7).
What is the site of bacterial DNA required for integration of lambda phage DNA known as?
Lambda phage exists as a phage but also integrates into the E. coli chromosome at the attB site to form a prophage. The integration reaction occurs when integrase makes staggered cuts in the center of the phage attP site and in the center of the bacterial site attB.
What does the repressor bind to?
Repressor A repressor, as related to genomics, is a protein that inhibits the expression of one or more genes. The repressor protein works by binding to the promoter region of the gene(s), which prevents the production of messenger RNA (mRNA).
What are the different types of DNA-binding domains?
Although each of these proteins has unique features, most bind to DNA as homodimers or heterodimers and recognize DNA through one of a small number of structural motifs. The common motifs include the helix-turn-helix, the homeodomain, the leucine zipper, the helix-loop-helix, and zinc fingers of several types.
Is a repressor a transcription factor?
According to the conventional wisdom, transcription factors are typically classified as “activators” or “repressors”. Activators recruit coactivators, resulting in gene activation, while repressors recruit corepressors, leading to transcriptional repression.
Is Cro a repressor?
Is Cro protein a dimer?
Together the Cro and cI repressors form a helix-turn-helix (HTH) superfamily. The lambda Cro repressor binds to DNA as a highly flexible dimer.
What is the use of lambda DNA?
Lambda DNA (48,502 bp) may be used as a molecular weight size marker during nucleic acid gel analysis following digestion with a restriction enzyme (such as HindIII). Lambda DNA can also be used as a substrate in restriction enzyme activity assays.
How many base pairs are in lambda DNA?
48,502 base pairs
Lambda DNA is 48,502 base pairs in length.