Genes ectopic

Lufkin et al. (1992) also used a homeobox gene promoter exchange to drive misexpression of the Hox-4.2 gene. The Hox-1.6 promoter was observed to extend the anterior transcription boundary, and this region of ectopic expression gave a number of abnormalities, including absence... 

The most dramatic illustration of the evolutionary conservation of homeobox genes comes from experiments that swap Drosophila and mammalian cognates and test for functional equivalence. McGinnis and co-workers have reported remarkable phenotypic similarities in flies that misexpress Drosophila homeobox genes or their mammalian counterparts. Indeed, this ectopic expression assay in Drosophila indicates that the Drosophila and cognate mammalian homeobox proteins are essentially functionally identical. 

Balling, R., Mutter, G., Gruss, R, and Kessel, M. (1989). Craniofacial abnormalities induced by ectopic expression of the homeobox gene Hox-1.1 in transgenic mice. Cell 58 337-347. 

Lufkin, T., Mark, M., Hart, C. P Dolle, R, LeMeur, M., and Chambon, P. (1992). Homeotic transformation of the occipital bones of the skull by ectopic expression of a homeobox gene. Nature 359 835-841. 

Schneuwly, S., Klemenz, R and Gehring, W. J. (1987). Redesigning the body plan of Drosophila by ectopic expression of the homeotic gene Antennapedia. Nature 325 816-818. ... 

McMahon In terms of the model you are presenting that H19 might have a functional role, what has been done with regard to gene targeting to remove the H19 transcriptional locus or to ectopically express it in transgenics ... 

Thompson, A. J., A. C. Jackson et al. (2000b). Ectopic expression of a tomato 9-cw-epoxycarotcnoid dioxygenase gene causes over-production of abscisic acid. Plant J. 23(3) 363-374. 

Rao, S.S., Chu, C. and Kohtz, D.S. (1994) Ectopic expression of cyclin D1 prevents activation of gene transcription by myogenic basic helix-loop-helix regulators. Molecular and Cellular Biology 14, 5259—5267. 

Reverse genetic approaches start with a sequence and attempt to identify a function for the gene. This can be done by using PCR-based screens on DNA from insertionally mutagenized populations, ectopic misexpression of the gene, and expression studies, e.g., with RT-PCR or microarray analyses. 

The connection between DNA methylation and gene expression was first noticed when undifferentiated cells in culture were treated with the methylation inhibitor 5-azacytidine inhibition of methylation led to the appearance of stably inherited differentiated cell types and activation of previously silenced genes [107,108]. Ectopic DNA methylation inhibits gene expression [109], whereas drug-inhibition of methylation induces the expression of certain genes [110]. Transfection experiments... 

Figure 7 shows the effect of ectopic administration of T3 to the developing zebrafish embryo. At nontoxic concentration (50 nM), only a moderate fraction (less than 5%) of the zebrafish transcriptome shows significant changes. Ossification, visual processes, and the hematopoietic system were the physiological processes most affected by the treatment, in a pattern consistent with an advancement of the development in these particular functions (Fig. 7b). Genes involved in these three processes are known targets for TDCs during metamorphosis in amphibians, teleost fishes, and lampreys [54—60], and constitute molecular counterparts of different endpoints used to test for TDC in amphibians [56, 58]. Therefore, they are excellent candidates for markers of thyroid disruptors in zebrafish at early developmental stages. Chapter 14 provides a more in-deep description of the developmental effects of thyroid disruption in zebrafish embryos.

Rescue experiments Target noncoding sequence 3 imtranslated regions (UTRs), alternatively 5 UTRs, can be targeted by siRNA rescue can be performed by ectopically expressed genes lacking UTRs... 

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