Northern blotting

Northern blots Northern blots are very similar to Southern blots (see Figure 32.12, p. 453), except that the original sample contains a mixture of mRNA molecules that are separated by electrophoresis, then transferred to a membrane and hybridized to a... 

Western blot Northern blot Radioimmunoassay Western blot ELISA (synaptosomes)... 

Northern blotting. An experimental technique in which RNA molecules, after gel electrophoresis, are blotted to a membrane and then incubated with a radioactive probe that hybridizes to complementary sequences, demonstrating their presence on the blot. Northern blotting is used to detect specific RNA sequences in a mixture of RNA molecules. 

Probes labeled directly with HRP have been used in many membrane hybridization applications (5,6), including Southern blots. Northern blots, colony and plaque screening, PCR product detection/ identification, YAC clone screening, and RFLP analysis. 

Southern Blot, Northern Blot, and Western Blot... 

Northern Blot Northern blot is used to separate single-stranded RNA. Formalde-hyde/agarose gel is used for the electrophoresis. The fragments of RNA are then transferred to a cellulose filter from the gel and are hybridized with a specific radiolabeled probe as in the case of the Southern blot. 

The emission yield from the horseradish peroxidase (HRP)-catalyzed luminol oxidations can be kicreased as much as a thousandfold upon addition of substituted phenols, eg, -iodophenol, -phenylphenol, or 6-hydroxybenzothiazole (119). Enhanced chemiluminescence, as this phenomenon is termed, has been the basis for several very sensitive immunometric assays that surpass the sensitivity of radioassay (120) techniques and has also been developed for detection of nucleic acid probes ia dot-slot. Southern, and Northern blot formats (121). 

The northern blotting technique is similar to the Southern blotting technique with the exception that northern blots detect specific sequences of RNA, not DNA. 

Northern blot A method for transferring RNA from an agarose gel to a nitrocellulose filter, on which the RNA can be detected by a suitable probe. 

Signal The end product observed when a specific sequence of DNA or RNA is detected by autoradiography or some other method. Hybridization with a complementary radioactive polynucleotide (eg, by Southern or Northern blotting) is commonly used to generate the signal. 

Detection of expression of mRNAs in tissues by Northern blotting using one or more fragments of the gene as a probe The mRNA should be expressed in affected tissues. 

B. Northern blot analysis of total RNA extracted from hypocotyls of P. vulgaris and hybridised to a radioactive pg/p-specific probe. 

Northern blot analysis revealed that expression of NHE-1 is tissue-specific with highest transcript abundance in stomach and minimal levels in liver and skeletal muscle. Moreover, there is physiological evidence that certain segments of the nephron lack a basolateral Na /H" exchanger [76]. Using RT-PCR, Krapf and Solioz [77] observed that NHE-1 transcripts are not detectable in SI and S2 segments of superficial nephrons. 

With regard to the potential function of Raf-1 in mammalian germ cells, the testis is a site of abundant expression of c-ra/-l mRNAs. Northern blot and in situ hybridization analysis has shown that although c-ra/-l is expressed most abundantly in early pachytene spermatocytes, some transcripts were also detected in germ cells from type A and B spermatogonia through to the round spermatid stage (Wolfes et al., 1989 Wadewitz et al., 1993). 

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