Transcription factors multiple

Originally described in the immune system, NFAT proteins comprise a family of transcriptional factors that play key roles in many cellular processes that control not only immune responses but also the development, regulation, and differentiation of many other tissues. Activation of NFAT proteins results in the expression of specific sets of genes that regulate multiple cell functions [1,2]. 

While much has been learned about the HS response, our understanding is still incomplete. Why, for instance, are there multiple HS transcription factors Are some of these factors utilized during development and cellular differentiation ... 

RNA polymerases interact with unique cw-active regions of genes, termed promoters, in order to form preinitiation complexes (PICs) capable of initiation. In eukaryotes the process of PIC formation is facilitated by multiple general transcription factors (GTFs), TFIIA, B, D, E, F, and H. 

Finally, the binding of specific transcription factors to cognate DNA elements may result in disruption of nucleosomal structure. Many eukaryotic genes have multiple protein-binding DNA elements. The serial binding of transcription factors to these elements—in a combinatorial fashion—may either directly disrupt the structure of the nucleosome or prevent its re-formation or recruit, via protein-protein interactions, multiprotein coactivator complexes that have the ability to covalently modify or remodel nucleosomes. These reactions result in chromatin-level structural changes that in the end increase DNA accessibifity to other factors and the transcription machinery. 

There are multiple levels of integration within the transcriptional regulator network. Part of the complexity of control lies in the large number of different factors available to generate cell-type-specific transcriptional regulation. More importantly, control over the expression and functional state of these numerous transcription factors is a source of considerable complexity and opportunity for... 

Finally, development of drugs targeted toward modification of kinases and phosphatases required for activation or inhibition of particular transcription factors is a promising therapeutic approach. The problem with this paradigm is the specificity of the kinases and phosphatases, since they will often act enzymatically on multiple proteins (see Chs 24 and 25). Furthermore, such drugs often lack specificity and may interact with multiple kinases or phosphatases. 

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