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Isolation of a polyubiquitin promoter and its expression in transgenic potato plants. 总被引:15,自引:1,他引:14 下载免费PDF全文
A polyubiquitin clone (ubi7) was isolated from a potato (Solanum tuberosum) genomic library using a copy-specific probe from a stress-induced ubiquitin cDNA. The genomic clone contained a 569-bp intron immediately 5' to the initiation codon for the first ubiquitin-coding unit. Two chimeric beta-glucuronidase (GUS) fusion transgenes were introduced into potato. The first contained GUS fused to a 1156-bp promoter fragment containing only 5' flanking and 5' untranslated sequences from ubi7. The second transgene contained GUS translationally fused to the carboxy terminus of the first ubiquitin-coding unit and thus included the intron present in the 5' untranslated region of the polyubiquitin gene. Both ubi7-GUS transgenes were activated by wounding in tuber tissue and in leaves by application of exogenous methyl jasmonate. They were also expressed constitutively in the potato tuber peel (outer 1-2 mm). Both transgenes were actively expressed in mature leaves. Exceptionally high levels of expression were observed in senescent leaves. Transgenic clones containing the ubi7 intron and the first ubiquitin-coding unit showed GUS expression levels at least 10 times higher than clones containing GUS fused to the intronless promoter. 相似文献
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B K Chow V Ting F Tufaro R T MacGillivray 《The Journal of biological chemistry》1991,266(28):18927-18933
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Transferrin is a major plasma protein that transports iron to proliferating cells throughout the body. A clone containing the 5' region of the human transferrin gene has been isolated and characterized. A 14 kb EcoRI fragment was identified that contained the first 8 exons of the transferrin gene and 3.6 kb of its 5' flanking region. Conserved sequences identical or homologous to regulatory elements responding to heavy metals, glucocorticoid receptor and a putative acute phase reaction signal were identified in the 5'flanking region and intron 1. Also, the regulatory region of the transferrin gene contains a 14-bp sequence which closely matches sequences found in the interleukin-2 and gamma-interferon genes. All three genes are expressed by T lymphocytes before proliferation. A secondary loop structure similar to that proposed for the ovotransferrin gene can be formed by sequences in the 5' untranslated region of the transferrin mRNA. 相似文献
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