Project description:The magnocellullar neurons (MCNs) of the supraoptic nucleus (SON) of the hypothalamus are the principle source of the neuropeptide hormone vasopressin (VP), which has a crucial role in osmoregulation. Physiological activation of the SON by dehydration results is a massive release of VP from stores in posterior pituitary axon terminals into the general circulation. By binding to V2-type receptors located in the kidney, VP decrease the amount of water lost in urine. Osmotic activation of the SON is accompanied by a dramatic morphological and functional remodelling. We have sought to understand the mechanistic basis of this plasticity in terms of the differential expression of genes. To identify such genes, we adopted a completely unbiased and global approach based on Suppressive Subtractive Hybridisation-Polymerase Chain Reaction (SSH-PCR) Using this method, we generated a library of clones putatively differentially expressed in control vs dehydrated SON. In order to rapidly screen this library, 1152 of these clones were subjected to microarray analysis, resulting in the identification of 459 differentially expressed clones, 56 of which were sequenced. Many of these clones are expressed sequences that are new to science. Four of these were shown by in situ hybridisation (ISH) to be significantly up- or down-regulated in the SON following dehydration. These genes may represent novel effectors or mediators of SON physiological remodelling. Keywords: dehydrated, SON, clone
Project description:The magnocellullar neurons (MCNs) of the supraoptic nucleus (SON) of the hypothalamus are the principle source of the neuropeptide hormone vasopressin (VP), which has a crucial role in osmoregulation. Physiological activation of the SON by dehydration results is a massive release of VP from stores in posterior pituitary axon terminals into the general circulation. By binding to V2-type receptors located in the kidney, VP decrease the amount of water lost in urine. Osmotic activation of the SON is accompanied by a dramatic morphological and functional remodelling. We have sought to understand the mechanistic basis of this plasticity in terms of the differential expression of genes. To identify such genes, we adopted a completely unbiased and global approach based on Suppressive Subtractive Hybridisation-Polymerase Chain Reaction (SSH-PCR) Using this method, we generated a library of clones putatively differentially expressed in control vs dehydrated SON. In order to rapidly screen this library, 1152 of these clones were subjected to microarray analysis, resulting in the identification of 459 differentially expressed clones, 56 of which were sequenced. Many of these clones are expressed sequences that are new to science. Four of these were shown by in situ hybridisation (ISH) to be significantly up- or down-regulated in the SON following dehydration. These genes may represent novel effectors or mediators of SON physiological remodelling. 4 chips were hybridised with control SON and compared to 4 chips hybridised with dehydrated SON
Project description:Screening cDNA clones from SSH library by hybridization with cDNA used to construct the library. Treated samples were drought-stressed cowpea plants, and control samples were cowpea plants subjected to a standard watering regime. cDNA clones from forward and reverse libraries are spotted on the same array, but data from each library were analysed separately after normalization using SSHscreen software (http://microarray.up.ac.za/SSHscreen ) to calculate Enrichment Ratio 3 (ER3) and Enrichment Ratio 2 (ER2) values for each clone. ER3 is a measure of differential expression, and was determined using a set of hybridizations with unsubtracted treated (UT) and unsubtracted control (UC) cDNA. ER2 is a measure of the relative abundance of a clone's transcript in the original tester sample, relative to other transcripts in the sample prior to the SSH process. ER2 for the forward library was determined using a set of hybridizations with subtracted treated (ST) and unsubtracted treated (UT) cDNA. ER2 for the reverse library is determined using a set of hybridizations with subtracted control (SC) and unsubtracted control (UC) cDNA.
Project description:Screening cDNA clones from SSH library by hybridization with cDNA used to construct the library. Treated samples were drought-stressed cowpea plants, and control samples were cowpea plants subjected to a standard watering regime. cDNA clones from forward and reverse libraries are spotted on the same array, but data from each library were analysed separately after normalization using SSHscreen software (http://microarray.up.ac.za/SSHscreen ) to calculate Enrichment Ratio 3 (ER3) and Enrichment Ratio 2 (ER2) values for each clone. ER3 is a measure of differential expression, and was determined using a set of hybridizations with unsubtracted treated (UT) and unsubtracted control (UC) cDNA. ER2 is a measure of the relative abundance of a clone's transcript in the original tester sample, relative to other transcripts in the sample prior to the SSH process. ER2 for the forward library was determined using a set of hybridizations with subtracted treated (ST) and unsubtracted treated (UT) cDNA. ER2 for the reverse library is determined using a set of hybridizations with subtracted control (SC) and unsubtracted control (UC) cDNA. Direct comparison of UT and UC cDNAs to calculate ER3 values for F and R library, including dye swaps and replicate arrays. Direct comparison of ST and UT cDNAs to calculate ER2 values for F library, including dye swaps and replicate arrays. Direct comparison of SC and UC cDNAs to calculate ER2 values for R library, including dye swaps and replicate arrays.