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- Zhang, Hong, et al.
(författare)
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K-ras mutations in colorectal adenocarcinomas and neighbouring transitional mucosa.
- 1998
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Ingår i: European Journal of Cancer. - 0959-8049 .- 1879-0852. ; 34:13, s. 2053-2057
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Tidskriftsartikel (refereegranskat)abstract
- The K-ras gene in codons 12 and 13 was investigated using allele-specific polymerase chain reaction in matched normal mucosa (n = 106), transitional mucosa (n = 69) and tumours (n = 149) from 149 patients with colorectal adenocarcinomas. K-ras mutations in codon 12 were detected in 41/149 (28%) of tumours and 4/69 (6%) of transitional mucosa samples, but not in the normal mucosa. Further, mutation rates were increased in younger patients (P = 0.001) and in mucinous carcinomas (50%) compared with well differentiated (17%), moderately differentiated (26%) or poorly differentiated (24%) tumours. Our findings indicate that mucinous carcinoma may represent a distinct genetic entity.
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- Zhang, Xiao-Qun, et al.
(författare)
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Specific expression in mouse mesoderm- and neural crest-derived tissues of a human PDGFRA promoter/lacZ transgene
- 1998
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Ingår i: Mechanisms of Development. - 0925-4773 .- 1872-6356. ; 70:1-2, s. 167-180
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Tidskriftsartikel (refereegranskat)abstract
- The platelet-derived growth factor alpha-receptor (PDGFR-alpha) displays a lineage-specific expression pattern in the mouse embryo and is required for normal development of mesoderm and cephalic neural crest derivatives. The purpose of the present study was to demonstrate the in vivo promoter function of genomic DNA fragments representing the 5'-flanking part of the human PDGFRA gene. 2.2, 0.9 and 0.4 kb PDGFRA promoter fragments, ligated to a lacZ reporter gene, were microinjected into fertilized mouse eggs and transgenic mouse lines were established. The expression patterns were basically similar in the 2.2 and 0.9 kb lines and overlapped grossly the endogenous Pdgfra gene expression pattern. The transgenic line with the highest expression level was chosen for detailed analysis. Expression was, as expected, mainly confined to tissues of mesodermal and neural crest origin. No expression was found in epithelial tissues of endo- or ectodermal origin. The promoter fragments were also active in neuroepithelium and in certain neuronal cell types that did not faithfully express PDGFR-alpha mRNA, while they failed to specify reporter expression in PDGFR-alpha expressing O-2A progenitor cells and other glial elements of the central nervous system. Thus, the isolated human PDGFRA promoter contains most but not all of the regulatory elements that are necessary to establish tissue specific gene expression during development.
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