Plasmid Add-back
Plasmid Add-back - Related Videos
08:16
Plasmid Purification
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2023
Plasmid purification is a technique used to isolate and purify plasmid DNA from genomic DNA, proteins, ribosomes, and the bacterial cell wall. A plasmid is a small, circular, double-stranded DNA that is used as a carrier of specific DNA molecules. When introduced into a host organism via transformation, a plasmid will be replicated, creating numerous copies of the DNA fragment under study. In this video, a step-by-step generalized procedure is described for how to perform plasmid purification.
07:11
Homemade Site Directed Mutagenesis of Whole Plasmids
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Cited by 92 •
2009
Site directed mutagenesis of whole plasmids is a simple way to create slightly different variations of an original plasmid. Here we demonstrate an easy and cost effective way to introduce base substitutions into a plasmid using standard reagents.
01:28
Plasmids
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2025
Plasmids are extrachromosomal DNA molecules found in bacteria, archaea, and some eukaryotic microbes like yeast. These small, circular DNA structures typically contain fewer than 30 genes, although some may exist linearly. Plasmids vary in their number within a cell, known as copy number. Single-copy plasmids are present in one copy per cell and multi-copy plasmids are present in multiple copies, reaching over 100 copies per cell.Plasmids usually replicate independently of the chromosomal DNA...
02:41
Amplification of a Suicide Plasmid in a Bacterial Host
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2025
Source: Tomás, J. M., et al. Generation of Null Mutants to Elucidate the Role of Bacterial Glycosyltransferases in Bacterial Motility. J. Vis. Exp. (2022).This video demonstrates the initiator-dependent amplification of a suicide plasmid in E. coli. The plasmid, which carries an antibiotic resistance gene, replicates only in the presence of an initiator protein encoded by the host. After electroporation and incubation in recovery medium, the mixture is plated on antibiotic-containing agar.
08:57
High-throughput Yeast Plasmid Overexpression Screen
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Cited by 12 •
2011
Here we describe a plasmid overexpression screen in Saccharomyces cerevisiae, using an arrayed plasmid library and a high-throughput yeast transformation protocol with a liquid handling robot.
FAQs
Restoration of the missing trait strengthens the causal link between a gene and a biological function. If a mutant or gene-deleted organism regains a phenotype after receiving the relevant genetic sequence, the result supports the idea that loss of that gene caused the defect. This evidence is especially useful for validating knockout or knockdown findings and separating a specific genetic effect from broader secondary changes.
Plasmid add-back can reintroduce more than a coding sequence. The construct may carry the target gene, its regulatory region, or a functional variant, depending on the question being tested. Comparing these forms can help investigators examine whether the phenotype depends on the gene product, its regulation, or a particular functional version, while the plasmid must remain compatible with the recipient cells.
Controls establish whether an observed change is attributable to the introduced genetic material. Researchers compare the deficient organism with appropriate control conditions and assess the same relevant traits, such as growth or expression. These comparisons help distinguish restoration caused by the add-back from changes that arise secondarily during mutation, gene deletion, or experimental handling.
An experiment generally begins by cloning the target gene, regulatory region, or functional variant into a compatible plasmid. The resulting construct is then introduced into the mutant or gene-deleted cells. Researchers compare those cells with appropriate controls and evaluate growth, expression, or another relevant phenotype. This sequence connects construct design with functional interpretation.
Growth and gene expression are two central readouts, but the comparison can also include other phenotypic traits relevant to the biological question. A restored growth pattern may indicate recovery of a cellular function, whereas expression measurements can show whether the introduced sequence is associated with the expected molecular change. Results are interpreted against controls.
Researchers commonly apply plasmid add-back after a knockout or knockdown has produced a candidate phenotype. Reintroducing the relevant genetic material provides a follow-up test of whether that phenotype is connected to the disrupted gene rather than only to an indirect consequence of the experiment. This makes the method useful for functional genomics and gene-function studies.
In biology, the technique is particularly relevant to microbial genetics, molecular biology, and functional genomics. Its value extends across these areas because the same experimental logic can connect a disrupted gene with changes in growth, expression, or another phenotype. By restoring the relevant genetic element and comparing outcomes, investigators can strengthen functional assignments from genetic experiments.