Biology Reference
In-Depth Information
The tissues that comprise organs typically undergo their own TH-
induced changes independent of other associated tissues, and they have their
own tissue-specific TH-response genes, such as sonic hedgehog in the intes-
tinal epithelium and stromelysin-3 in fibroblasts. Also, the same tissue can
undergo distinct responses depending on their location in the body, for ex-
ample, fibroblasts and epidermis in tail versus body. However, tissues within
an organ may be of low abundance and critical cells within tissues (such as
stem cells) will be rare. In these cases, mRNA from rare cells may not be well
represented in the large pool of mRNA from abundant cells and thus gene
expression changes may not be detectable from the rare cells using micro-
array. Special techniques, such as dissecting out particular tissues from an or-
gan or isolating particular cells using laser capture microdissection may allow
detection of rare but critical TH-induced gene expression changes. Also,
due to the nature of how the microarray works, low abundance, but high
fold-change genes may not be detected. For example, TH/bZIP was iden-
tified using subtractive hybridization and is a very high fold-change gene,
but it is often not detected using microarrays due to its apparent low abun-
dance even when induced. In addition to TH/bZIP, there may be other
such potentially critical genes, which may yet be detected by other means,
such as transcriptomics or RNA-seq.
ACKNOWLEDGMENTS
This publication was made possible by University of Cincinnati Dissertation Completion
Fellowship to S. S. K. and NSF IOS 0950538 to D. R. B.
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