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cDNA Population (cdna + population)
Selected AbstractsPossible role of Hes5 for the rostrocaudal polarity formation of the tectumDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 3 2004Jun Kimura The alar plate of the mesencephalon differentiates into the optic tectum. Retinal fibers project to the tectum topographically in a retinotopic manner. Engrailed (En) is responsible for the tectum polarity formation and regionalization. Former study indicated the presence of the molecule whose expression is repressed by En and that represses the isthmus-related gene expression. To isolate such molecules, we constructed a subtracted library between cDNA population of the normal rostral mesencephalon and of the rostral mesencephalon that misexpresses En2. From the library, we isolated cHes5, a chicken homolog of Drosophila hairy/Enhancer of split. cHes5 begins to be expressed in the rostral part of the E2 mesencephalon, and spreads to caudal mesencephalon by E3. To our expectation, cHes5 expression was repressed by En2. Furthermore, misexpression of cHes5 in the mesencephalon inhibited expression of ephrinA2, a marker of caudal mesencephalon. An active repressor form of Hes5, which is a chimeric molecule of Hes5 and repressor domain of En2, showed a similar but more severe phenotype. The results indicate that Hes5 is regulated by En and is responsible for rostral identity of mesencephalon by repressing ephrinA2. [source] Characterisation of gene expression in bovine adipose tissue before and after fatteningANIMAL GENETICS, Issue 3 2000M Oishi Summary It has been reported that fattening causes bovine adipose tissue development associated with an enlargement in adipocyte cell size. As a first study to elucidate mechanisms of bovine adipose tissue development during fattening, our experiment was designed to characterise gene expression in bovine adipose tissue before and after fattening. We randomly isolated a large number of cDNA clones derived from bovine adipose tissue before and after fattening. Sequence analysis of the isolated clones showed that 3 and 10 clones from before and after fattening, respectively, correspond to genes related to adipocyte development and/or function in the adipose tissue. In addition, we isolated cDNA clones that possess negative signal by hybridising the cDNA population from the adipose tissue after fattening with that before fattening as a probe. As a result, we identified five types of transcripts observed in the adipose tissue after fattening but not before fattening. Two of the five are likely to encode bovine orthologs of phospholipase A2 and RNA helicase p68, while the other three represent unknown genes. Further functional investigation of the identified genes might lead to elucidation of mechanisms of bovine adipose tissue development during fattening. [source] Genome-wide analysis of the general stress response in Bacillus subtilisMOLECULAR MICROBIOLOGY, Issue 4 2001Chester W. Price Bacteria respond to diverse growth-limiting stresses by producing a large set of general stress proteins. In Bacillus subtilis and related Gram-positive pathogens, this response is governed by the ,B transcription factor. To establish the range of cellular functions associated with the general stress response, we compared the transcriptional profiles of wild and mutant strains under conditions that induce ,B activity. Macroarrays representing more than 3900 annotated reading frames of the B. subtilis genome were hybridized to 33P-labelled cDNA populations derived from (i) wild-type and sigB mutant strains that had been subjected to ethanol stress; and (ii) a strain in which ,B expression was controlled by an inducible promoter. On the basis of their significant ,B -dependent expression in three independent experiments, we identified 127 genes as prime candidates for members of the ,B regulon. Of these genes, 30 were known previously or inferred to be ,B dependent by other means. To assist in the analysis of the 97 new genes, we constructed hidden Markov models (HMM) that identified possible ,B recognition sequences preceding 21 of them. To test the HMM and to provide an independent validation of the hybridization experiments, we mapped the ,B -dependent messages for seven representative genes. For all seven, the 5, end of the message lay near typical ,B recognition sequences, and these had been predicted correctly by the HMM for five of the seven examples. Lastly, all 127 gene products were assigned to functional groups by considering their similarity to known proteins. Notably, products with a direct protective function were in the minority. Instead, the general stress response increased relative message levels for known or predicted regulatory proteins, for transporters controlling solute influx and efflux, including potential drug efflux pumps, and for products implicated in carbon metabolism, envelope function and macromolecular turnover. [source] Identification of potato genes induced during colonization by Phytophthora infestansMOLECULAR PLANT PATHOLOGY, Issue 3 2001Katinka Beyer Summary Suppression Subtractive Hybridization (SSH) was applied in a search for genes induced during the compatible interaction between Phytophthora infestans and potato. Using potato leaves that had been treated with benzo(1,2,3)thiadiazole-7-carbothioic acid S-methylester (BTH) as the control tissue, a low redundancy library with a relatively low frequency of the classic plant Pathogenesis-Related (PR) genes was generated. 288 of the clones were screened for induced sequences using Inverse Northern analysis (hybridizing the arrayed clones with radiolabelled cDNA populations). Of the 75 clones that were detectable by this method, 43 appeared to be induced. Eleven of these clones were then analysed by total RNA blot analysis, and elevation of transcript levels during P. infestans infection was confirmed for 10 of them. Some of the cDNAs analysed by RNA blot analysis have homology to genes already known to be induced during infection, e.g. to ,-1,3-glucanase. Another group of cDNAs have homology to enzymes involved in detoxification: gamma-glutamylcysteine synthetase, cytochrome P450, glutathione S-transferase and an MRP-type ABC transporter. Other infection induced cDNAs encode putative proteins that have not previously been reported to be induced by infection: e.g. the ER-located chaperone BiP, and a homologue of Aspergillus nidulans SudD, which was isolated as a suppressor of a mutation in chromosome disjunction. The differential library therefore presents the opportunity to analyse the metabolic changes occurring during infection, and the disease process itself in more detail. [source] | ||||||||||