Techniques used to Analyse DNA, RNA and Proteins
The products of gene expression (mRNA and proteins) can be measured by techniques such as the following:
Southern Blotting
Northern blots
Northern blots are very similar to southern blots except that the original sample contains a mixture of mRNA molecules that are separated by electrophoresis, then hybridized to a radioactive probe.
Southern Blotting vs Northern Blotting
Microarrays
Microarrays are used to determine the differing patterns of gene expression in two types of cells-
for example: normal and cancer cells.
The approximately 40,000 genes of the human genome translate into hundreds of thousands of proteins when alternate splicing and post translational modifications are considered. Enzyme linked immunosorbent assays (ELISAs) and western blots (immunoblots) are used to detect specific proteins
ELISAs
ELISAs are performed in the wells of plastic microtiter dish. The antigen (protein) is bound to the plastic of the dish. The probe used consists of an antibody specific for the particular proteins to be measured. The antibody is covalently bound to an enzyme, which will produce a colored produced can be used to determine the amount of protein (or antibody) in the sample to be tested.
Western blots
Western blots are also called immunoblots are similar to Southern blots, except that protein molecules in the sample separated by electrophoresis and blotted to a membrane. The probe is labeled antibody, which produces a band at the location of its antigen.
- Multiple Choice Questions on Blotting Techniques
MCQ on Blotting Techniques
Proteomics
Proteomics involves the study of all proteins expressed by a genome, including their relative abundance, distribution, post translational modifications, functions, and interactions with other macromolecules. Proteomics offers the potential of identifying new disease markers and drug targets.
Molecular Techniques used to Analyse DNA, RNA and Proteins
No
| Sample Analyzed
| Techniques
| Gel used
| Purpose
|
|---|---|---|---|---|
1
| DNA
| ASO (Allele Specific Oligonucleotides)
| No
| Detects DNA mutations
|
2
| DNA
| Southern Blot
| Yes
| Detects DNA changes
|
3
| RNA
| Northern Blot
| Yes
| Measures mRNA amounts
|
4
| RNA or cDNA
| Microarray
| No
| Measures many mRNA levels at once.
|
5
| Proteins
| Western blot
| Yes
| Measures protein amounts
|
6
| Proteins
| Proteomics
| Yes
| Measures abundance, distribution, post translational modification, functions, and interactions of cellular proteins
|
7
| Proteins or antibodies
| ELISA (Enzyme Linked Immunosorbent Assyas)
| No
| Detects proteins (antigens) or antibodies
|
Techniques used for Gene Expression Studies
