Structure, expression and function of chicken proto-oncogene c-ros.
Item
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Title
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Structure, expression and function of chicken proto-oncogene c-ros.
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Identifier
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AAI9405510
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identifier
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9405510
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Creator
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Chen, Jianmin.
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Contributor
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Adviser: Lu-Hai Wang
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Date
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1993
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Language
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English
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Publisher
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City University of New York.
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Subject
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Biology, Microbiology | Biology, Genetics | Biology, Molecular
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Abstract
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Proto-oncogene c-ros is the cellular counterpart of the transforming gene v-ros of avian sarcoma virus UR2 (Neckameyer et al., 1986; Chen et al., 1991). The transforming protein of UR2 is a gag-ros fusion polypeptide of 68-kDa with protein tyrosine kinase (PTK) activity (Feldman et al., 1982; Jong & Wang, 1987). Previous studies have shown that c-ros codes for a receptor-like PTK molecule (Neckameyer et al., 1986; Matsushime et al., 1986). However, the physiological function and potential ligand of the c-ros product remains unknown. In order to understand the function of the c-ros proto-oncogene, following aspects of c-ros were explored in my PH.D work: (1) Isolation and cloning of the c-ros cDNA. Using the v-ros DNA as a probe to screen chicken kidney cDNA libraries, I have isolated several overlapping cDNA clones and determined their sequences (Chen et al., 1991). Nucleotide sequence of the 8.1-kb c-ros cDNA shows that it codes for a transmembrane (TM) PTK molecule of 2311 amino acids (aa). (2) Functional characterization of the c-ros protein. Expression study showed that c-ros product is a 260 to 280-kDa glycosylated protein with very low kinase activity in the absence of ligand stimulation. The biochemical and biological properties of the c-ros protein and one of its activated variant were analyzed. (3) Analysis of the c-ros expression in vivo. Analysis of the c-ros RNA expression in various chicken tissues by RNase protection assay (RPA) and in situ hybridization showed that the c-ros expression is under tight temporal and spatial regulation. The tissue and cell type specific expression or c-ros suggests that it may play important roles in their development and mature functions. (4) Cloning and characterization of the c-ros promoter. A genomic DNA fragment corresponding to the potential c-ros promoter was isolated. Experiments of primer extension, RNase protection and functional demonstrations (CAT assay) were performed to verify that this region is indeed the c-ros promoter. One positive regulatory region was mapped by analysis of a series of deletion mutant.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
