Expression studies

Although freeze-fracture experiments have demonstrated that monomers are assembled into stable tetramers in the membranes, radiation inactivation studies and, later, expression studies revealed that each monomer is a functional water channel (Fig. lc). 

Homology screening. Using oligonucleotide probes based on known receptor sequences, search cDNA libraries for homologous sequences which may code for related receptors. The clones are then isolated and sequenced and used in expression studies to confirm the identity of the receptor. 

Expression studies in Xenopus oocytes or transfected cell lines originally suggested that functional GABA-activated chloride channels could be formed by receptor subunits of each class in isolation. However, much better expression occurs with two or more subunit types in combination and it is likely that most native receptors contain at least three different subunits. Co-expression of a and /I subunits results in the assembly of... 

Key findings that demonstrated that the 0 subunit is the essential component of L-type channels have come from studies of the channel activity of the expressed protein. Expression studies performed in mammalian liver fibroblasts have demonstrated that the oti subunit alone can form a channel [77] and contains the receptors for the DHPs, PAAs and diltiazem [64]. In very elegant studies using a mouse model of muscular dysgenesis it has been demonstrated that the ] subunit DNA can restore Ca currents and the charge movement that arises from the voltagesensing function of the channels to the mutant cells that normally lack these activities [21,78,79]. The restoration of these activities restores excitation-contraction coupling. Thus it is clear that the aj subunit is the major functional unit of L-type Ca channels. 

Bryant Not as far as I know. We have started ectopic expression studies. When we express them in imaginal discs they don t show a growth phenotype. They don t seem to be acting on a local level in this way. 

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. 

For ligand-gated ion channel receptor expression studies, stage V and VI oocytes are preferred (see earlier). Under a dissecting microscope, oocytes of this stage that are in good condition are sorted from the rest and then incubated at 16-18°C in MBM overnight. Incubation in hypertonic phosphate... 

Lee Ml, Kuo FC, Whitmore GA, Sklar J. 2000. Importance of replication in microarray gene expression studies statistical methods and evidence from repetitive cDNA hybridizations. Proc Natl Acad Sci USA 97 9834. 

Adjuvants enhancing HLA class I-restricted CTL responses are especially needed for treatment or prevention of chronic viral diseases and infections linked to intracellular pathogens, and for cancer immunotherapy. Among the very few adjuvants licensed for human use, we evaluated the capacity of IRIV to enhance HLA class I-restricted CTL responses in vitro. We addressed IRIV-elicited immune responses and the induction of CTL specific to IM58 66 and Melan-A/Mart-127-35 epitopes. Proliferation assays, cytokine expression studies, and phenotypes of CD4+ T-cells demonstrated that IRIV... 

Mechanisms of Disease biomarkers and molecular targets from microarray gene expression studies in prostate cancer. Nature Clinked Practices in Urology, 4, 677-687. 

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