Editing Northern blot (section)

==Advantages and disadvantages==
Analysis of gene expression can be done by several different methods including RT-PCR, RNase protection assays, microarrays, [[RNA-Seq]], serial analysis of gene expression (SAGE), as well as northern blotting.<ref name="Schlamp2008" /><ref name="Trayhurn1996" />  Microarrays are quite commonly used and are usually consistent with data obtained from northern blots; however, at times northern blotting is able to detect small changes in gene expression that microarrays cannot.<ref name=Taniguchi2001>{{cite journal | last1 = Taniguchi | first1 = M. | last2 = Miura | first2 = K. | last3 = Iwao | first3 = H. | last4 = Yamanaka | first4 = S. | year = 2001 | title = Quantitative Assessment of DNA Microarrays – Comparison with Northern Blot Analysis | journal = Genomics | volume = 71 | issue = 1| pages = 34–39 | doi = 10.1006/geno.2000.6427 | pmid = 11161795 }}</ref>  The advantage that microarrays have over northern blots is that thousands of genes can be visualized at a time, while northern blotting is usually looking at one or a small number of genes.<ref name="Baldwin1999" /><ref name="Taniguchi2001" />

A problem in northern blotting is often sample degradation by RNases (both endogenous to the sample and through environmental contamination), which can be avoided by proper sterilization of glassware and the use of RNase inhibitors such as DEPC ([[diethylpyrocarbonate]]).<ref name="Trayhurn1996" />  The chemicals used in most northern blots can be a risk to the researcher, since formaldehyde, radioactive material, ethidium bromide, DEPC, and UV light are all harmful under certain exposures.<ref name="Streit2009" />  Compared to RT-PCR, northern blotting has a low sensitivity, but it also has a high specificity, which is important to reduce false positive results.<ref name="Streit2009" />

The advantages of using northern blotting include the detection of RNA size, the observation of alternate splice products, the use of probes with partial homology, the quality and quantity of RNA can be measured on the gel prior to blotting, and the membranes can be stored and reprobed for years after blotting.<ref name="Streit2009" />

For northern blotting for the detection of [[acetylcholinesterase]] [[mRNA]] the nonradioactive technique was compared to a radioactive technique and found as sensitive as the radioactive one, but requires no protection against radiation and is less time-consuming.<ref>Kreft, K., Kreft, S., Komel, R., Grubič, Z. (2000). Nonradioactive northern blotting for the determination of acetylcholinesterase mRNA. Pflügers Arch – Eur J Physiol, 439:R66-R67</ref>