Nucleic acid hybridization Northern blotting

There are four main types of trancriptome analyses utilized in yeast mRNA profiling, each with different benefits and deficiencies (Table 3). The first two methods rely on arraying complementary nucleotide information on a grid with subsequent hybridization of a sample preparation. These methods are based on scaling up Northern blot technology of complementary nucleic acid hybridization to assess multiple transcripts... 

DNA adsorption properties were first studied using a variety of solid supports for classical analysis methods including Southern and Northern transfers, dot-blotting, colony hybridization and plaque-lifts [31,32]. Studies of the interactions between nucleic acids and nitrocellulose revealed that molecular weight, finite macromolecular conformation, ionic forces and weaker forces of attraction all play a role. DNA is retained on nitrocellulose only in... 

In situ hybridization was derived from the techniques of molecular hybridization of nucleic acids that are isolated from a particular cell population or tissue and bound to solid supports. Hybridization of such averaged membrane-bound nucleic acids identifies different classes of DNA (Southern blot) and RNA (Northern blot). However, ISH fills the gap between the detection of a specific sequence and its precise location within the tissue or the cell (Chevalier et al., 1997). 

Northern blotting was not named for its inventor, but as a companion technique that uses RNA rather than DNA as the test nucleic acid. RNA is transferred from the gel after electrophoresis onto a solid support followed by hybridization with a specific labeled probe. Because RNA molecules have defined lengths and are much shorter than genomic DNA, it is not necessary to cleave RNA before electrophoresis. However, because of the secondary structure of RNA, it is necessary to perform electrophoresis under denaturing... 

Solid phase hybridization is in most cases achieved on membranes. Target nucleic acid is immobilized and subsequently detected by a probe. This approach forms the basis of slot/dot blot hybridization, Northern and Southern hybridization and colony or plaque hybridization. Dot/slot blot hybridization (Kafatos et al., 1979) demonstrates the presence of target sequences but not their size. Although solid phase hybridization is convenient for hybrid/free probe separation, it has the disadvantages that nucleic acid is most often bound noncovalently and that targets are immobilized at fre-... 

An additional nucleic acid sequence, a probe, may be included in a reassociation reaction and form double strands with components of the initial DNA. This hybridization reaction is the basis of the Southern and northern blotting techniques used to determine if a known nucleic-acid sequence is present in a mixture of nucleic-acid sequences. 

DNA arrays, like more traditional hybridization techniques such as Southern and Northern blotting, make use of the fact that single-stranded nucleic acid species (DNA and RNA) that possess sequences complementary to each other will hybridize together with exquisite specificity to form double-stranded complexes. In the traditional approaches, the samples to be analyzed are distributed according to size by gel electrophoresis, transferred to and immobilized on solid membrane supports, and probed with specific, labeled complementary nucleic acid sequences. 

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