Cell type-specific gene expression

Losick, R and P. Stragier, Crisscross regulation of cell-type-specific gene expression during development in B. subtilis. Nature 355 601-604, 1992. 

Li W, Ishida T, Tachibana R, Almofti MR, Wang X, Kiwada H (2004) Cell type-specific gene expression, mediated by TFL-3, a cationic liposomal vector, is controlled by a posttranscription process of delivered plasmid DNA. Int J Pharm 276 67-74... 

Transcriptional activation is a highly cooperative process so that genes expressed in a specific type of cell are expressed only when the complete set of activators that control that gene are expressed and activated. As mentioned earlier, some of the transcription factors that control expression of the TTR gene in the liver are also expressed in intestinal and kidney cells. Yet the TTR gene is not expressed In these other tissues, since Its transcription requires two additional transcription factors expressed only in the liver. What mechanisms account for this highly cooperative action of transcription factors that Is critical to cell-type-specific gene expression ... 

Chung C Y, Seo H, Sonntag K C, et al. (2005). Cell type-specific gene expression of midbrain dopaminergic neurons reveals molecules involved in their vulnerability and protection. Human Molec. Genetics. 14 1709-1725. 

L. J. Eichner, P. S. Nelson, and A. Y. Liu. 2008. Correlation of mRNA and protein levels Cell type-specific gene expression of cluster designation antigens in the prostate. BMC Genomics 9 246. 

Weber, H., Heim, U., Borisjuk, L., and Wobus, U. 1995. Cell-type specific, coordinate expression of two ADPglucose pyrophosphorylase genes in relation to starch biosynthesis during seed development in Vicia faba L. Planta 195, 352-361. 

Our recent research suggests organ-, tissue-, and cell-specific localization of constitutive and induced terpenoid defense pathways in conifers. For example, linalool synthase (PaTPS-Lin) seems to be preferentially expressed in needles of Norway spruce and Sitka spruce with little or no expression in sterns. ft is also likely that expression of PaTPS-Lin in spruce needles is not associated with resin ducts but could reside in other cells involved with induced terpenoid emission. In contrast, we can speculate that most other mono-TPS and di-TPS are associated with epithelial cells of constitutive and induced resin ducts. The possible localization of conifer sesqui-TPS is difficult to predict. Furthermore, the exact spatial and temporal patterns of terpenoid pathway gene expression associated with traumatic resin duct development in the cambium zone and outer xylem remain to be studied at the tissue and cell level. In situ hybridization and immuno-localization of TPS will address these open questions. These methods have worked well in identifying cell type specific gene and protein expression of alkaloid formation in opium poppy Papaver somniferum) As the biochemistry of induced terpene defenses and the development of traumatic resin ducts have been well described in spruce, this system is ideal for future studies of tissue- and cell-specific localization of transcripts and proteins associated with oleoresin defense and induced volatile emissions in conifers. In addition, the advent of laser dissection microscopy techniques presents a fascinating means by which to further address RNA and protein analysis in a tissue-and cell-specific manner. These techniques, when applied to the cambium zone, xylem mother cells, and the epithelial cells that surround traumatic resin ducts, and will allow a temporal and spatial analysis of cellular functions occurring in the traumatic resin response. 

The ability of the leucine zipper proteins to form heterodimers greatly expands the repertoire of DNA-binding specificities that these proteins can display. As illustrated in Figure 10.19, for example, three distinct DNA-binding specificities could, in principle, be generated from two types of monomer, while six could be created from three types of monomer and so on. This is an example of combinatorial control, in which combinations of proteins, rather than individual proteins, control a cellular process. It is one of the most important mechanisms used by eucaryotic cells to control gene expression. 

Restrictive cell-type-specific expression of primary response genes. 

Kim, C. H., Kim, H. S., Cubells, J. F., 8c Kim, K. S. (1999). A previously undescribed intron and extensive 5 upstream sequence, but not Phox2a-mediated transactivation, are necessary for high level cell type-specific expression of the human norepinephrine transporter gene. /. Biol. Chem., 274, 6507-18. 

Differential Gene Expression -cell type specific -developmental-stage specific... 

Specific transcription factors bind to enhancer regions or, in a few cases, to silencers and mod-ciate the formation of the initiation complex, thus regulating the rate of initiation of transcription. Each gene contains a variety of enhancer or silencer sequences in its regulatory region. The exact combination of specific transcription factors available (and active) in a particular cell at a particular time determines which genes will be transcribed at what rates, because specific transcription factors are proteins, their expression can be cell-type specific.. Additionally, hormones may regulate the activity of some specific transcription factors. Examples include steroid receptors and the CREB protein. 

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