2-D electrophoresis begins with 1-D electrophoresis but then separates the molecules by a second property in a direction 90 degrees from the first. In 1-D electrophoresis, proteins (or other molecules) are separated in one dimension, so that all the proteins/molecules will lie along a lane but that the molecules are spread out across a 2-D gel. The two dimensions that proteins are separated into using this technique can be isoelectric point, protein complex mass in the native state, and protein mass. This technique is most commonly used when trying to establish a proteome for an organism, but can be used to demonstrate changes in expression, in the change in size/concentration of the spot on the gel that corresponds to the target protein.

Reporter assay using the beta-galactosidase (lacZ) gene. The lacZ gene is typically fused to the promoter of interest. Differential regulation of the promoter mediated by the TF is assessed by induction of the system and evaluation of lacZ expression. Bacteria expressing lacZ appear blue when grown on a X-gal medium. The assay is often performed using a plasmid borne construction on a lacZ(def) strain.

As with motif discovery, TF-binding sites search benefits from a comparative genomics approach. Searching a single genome for TFBS will yield very noisy results. If a number of related genomes are searched, then the search results can be compared and strengthened by requiring that a site be located, for instance, in the promoter region of the same gene for at least two or three species. As in the case of motif discovery, these methods are not often applied to verify experimental results, but can be used to guide experimental research. For instance, comparative genomics searches can be implemented to detect good candidate sites, which are then verified using an experimental technique.

Electro-mobility shift-assays (or gel retardation assays) are a standard way of assessing TF-binding. A fragment of DNA of interest is amplified and labeled with a fluorophore. The fragment is left to incubate in a solution containing abundant TF and non-specific DNA (e.g. randomly cleaved DNA from salmon sperm, of all things) and then a gel is run with the incubated sample and a control (sample that has not been in contact with the TF). If the TF has bound the sample, the complex will migrate more slowly than unbound DNA through the gel, and this retarded band can be used as evidence of binding. The unspecific DNA ensures that the binding is specific to the fragment of interest and that any non-specific DNA-binding proteins left-over in the TF purification will bind there, instead of on the fragment of interest. EMSAs are typically carried out in a bunch of fragments, shown as multiple double (control+experiment) lanes in a wide picture. Certain additional controls are run in at least one of the fragments to ascertain specificity. In the most basic of these, specific competitor (the fragment of interest or a known positive control, unlabelled) is added to the reaction. This should sequester the TF and hence make the retardation band disappear, proving that the binding is indeed specific

2-D electrophoresis begins with 1-D electrophoresis but then separates the molecules by a second property in a direction 90 degrees from the first. In 1-D electrophoresis, proteins (or other molecules) are separated in one dimension, so that all the proteins/molecules will lie along a lane but that the molecules are spread out across a 2-D gel. The two dimensions that proteins are separated into using this technique can be isoelectric point, protein complex mass in the native state, and protein mass. This technique is most commonly used when trying to establish a proteome for an organism, but can be used to demonstrate changes in expression, in the change in size/concentration of the spot on the gel that corresponds to the target protein.

Reporter assay using the beta-galactosidase (lacZ) gene. The lacZ gene is typically fused to the promoter of interest. Differential regulation of the promoter mediated by the TF is assessed by induction of the system and evaluation of lacZ expression. Bacteria expressing lacZ appear blue when grown on a X-gal medium. The assay is often performed using a plasmid borne construction on a lacZ(def) strain.

As with motif discovery, TF-binding sites search benefits from a comparative genomics approach. Searching a single genome for TFBS will yield very noisy results. If a number of related genomes are searched, then the search results can be compared and strengthened by requiring that a site be located, for instance, in the promoter region of the same gene for at least two or three species. As in the case of motif discovery, these methods are not often applied to verify experimental results, but can be used to guide experimental research. For instance, comparative genomics searches can be implemented to detect good candidate sites, which are then verified using an experimental technique.

Electro-mobility shift-assays (or gel retardation assays) are a standard way of assessing TF-binding. A fragment of DNA of interest is amplified and labeled with a fluorophore. The fragment is left to incubate in a solution containing abundant TF and non-specific DNA (e.g. randomly cleaved DNA from salmon sperm, of all things) and then a gel is run with the incubated sample and a control (sample that has not been in contact with the TF). If the TF has bound the sample, the complex will migrate more slowly than unbound DNA through the gel, and this retarded band can be used as evidence of binding. The unspecific DNA ensures that the binding is specific to the fragment of interest and that any non-specific DNA-binding proteins left-over in the TF purification will bind there, instead of on the fragment of interest. EMSAs are typically carried out in a bunch of fragments, shown as multiple double (control+experiment) lanes in a wide picture. Certain additional controls are run in at least one of the fragments to ascertain specificity. In the most basic of these, specific competitor (the fragment of interest or a known positive control, unlabelled) is added to the reaction. This should sequester the TF and hence make the retardation band disappear, proving that the binding is indeed specific

Reporter assay using the beta-galactosidase (lacZ) gene. The lacZ gene is typically fused to the promoter of interest. Differential regulation of the promoter mediated by the TF is assessed by induction of the system and evaluation of lacZ expression. Bacteria expressing lacZ appear blue when grown on a X-gal medium. The assay is often performed using a plasmid borne construction on a lacZ(def) strain.

As with motif discovery, TF-binding sites search benefits from a comparative genomics approach. Searching a single genome for TFBS will yield very noisy results. If a number of related genomes are searched, then the search results can be compared and strengthened by requiring that a site be located, for instance, in the promoter region of the same gene for at least two or three species. As in the case of motif discovery, these methods are not often applied to verify experimental results, but can be used to guide experimental research. For instance, comparative genomics searches can be implemented to detect good candidate sites, which are then verified using an experimental technique.

Reporter assay using the beta-galactosidase (lacZ) gene. The lacZ gene is typically fused to the promoter of interest. Differential regulation of the promoter mediated by the TF is assessed by induction of the system and evaluation of lacZ expression. Bacteria expressing lacZ appear blue when grown on a X-gal medium. The assay is often performed using a plasmid borne construction on a lacZ(def) strain.

As with motif discovery, TF-binding sites search benefits from a comparative genomics approach. Searching a single genome for TFBS will yield very noisy results. If a number of related genomes are searched, then the search results can be compared and strengthened by requiring that a site be located, for instance, in the promoter region of the same gene for at least two or three species. As in the case of motif discovery, these methods are not often applied to verify experimental results, but can be used to guide experimental research. For instance, comparative genomics searches can be implemented to detect good candidate sites, which are then verified using an experimental technique.

Electro-mobility shift-assays (or gel retardation assays) are a standard way of assessing TF-binding. A fragment of DNA of interest is amplified and labeled with a fluorophore. The fragment is left to incubate in a solution containing abundant TF and non-specific DNA (e.g. randomly cleaved DNA from salmon sperm, of all things) and then a gel is run with the incubated sample and a control (sample that has not been in contact with the TF). If the TF has bound the sample, the complex will migrate more slowly than unbound DNA through the gel, and this retarded band can be used as evidence of binding. The unspecific DNA ensures that the binding is specific to the fragment of interest and that any non-specific DNA-binding proteins left-over in the TF purification will bind there, instead of on the fragment of interest. EMSAs are typically carried out in a bunch of fragments, shown as multiple double (control+experiment) lanes in a wide picture. Certain additional controls are run in at least one of the fragments to ascertain specificity. In the most basic of these, specific competitor (the fragment of interest or a known positive control, unlabelled) is added to the reaction. This should sequester the TF and hence make the retardation band disappear, proving that the binding is indeed specific