Deletion of chromosome 6q is frequent in breast cancer, and the deletion often involves a region in 6q 14-q 16. At present, however, the underlying tumor suppressor gene has not been established. Based on a recent stu...Deletion of chromosome 6q is frequent in breast cancer, and the deletion often involves a region in 6q 14-q 16. At present, however, the underlying tumor suppressor gene has not been established. Based on a recent study identifying snoRNA U50 as a candidate for the 6q14-16 tumor suppressor gene in prostate cancer, we investigated whether U50 is also involved in breast cancer. PCR-based approaches showed that U50 underwent frequent genomic deletion and transcriptional downregulation in cell lines derived from breast cancer. Mutation screening identified the same 2-bp deletion of U50 as in prostate cancer in both cell lines and primary tumors from breast cancer, and the deletion was both somatic and in germline. Genotyping of a cohort of breast cancer cases and controls for the mutation demonstrated that, while homozygous genotype of the mutation was rare, its heterozygous genotype occurred more frequently in women with breast cancer. Functionally, re-expression of U50 resulted in the inhibition of colony formation in breast cancer cell lines. These results suggest that noncoding snoRNA U50 plays a role in the development and/or progression of breast cancer.展开更多
By constructing and screening the Schizosac-charomyces pombe nuclear cDNA library, a novel small nu-cleolar RNAs (snoRNA) was identified. The novel snoRNAdisplays structural features typical of C/D box snoRNA fam-ily ...By constructing and screening the Schizosac-charomyces pombe nuclear cDNA library, a novel small nu-cleolar RNAs (snoRNA) was identified. The novel snoRNAdisplays structural features typical of C/D box snoRNA fam-ily and possesses a 10-nt-long rRNA antisense element whichis predicted to guide the 2’-O-methylation of the fission yeast 25S rRNA at G940. As expected, the rRNA ribose-methyla-tion site predicted by the novel snoRNA was preciselymapped by a deoxynucleoside triphosphate concentration-dependent primer extension assay. The comparison of func-tional element of guide snoRNAs among eukaryotes reveals that the novel snoRNA is a partial counterpart of the bud-ding yeast snR60 and was termed snR60-II. snR60-II genenested in the intron of a non-coding RNA gene with an un-known function, which is the first example of a yeastsnoRNA encoded in an intron of a non-coding RNA gene.Furthermore, a number of yeast snR60 homologues were also identified from other fungi and fly. Our results reveal thatsnR60 exhibits diverse genomic organization in eukaryotes, implying the high mobility of snR60 gene in the course ofevolution.展开更多
From a specialized cDNA library, four novel box H/ACA snoRNAs, named GLsR22, GLsR23, GLsR24 and GLsR25, were identified from the primitive eukaryote, Giardia lamblia. Bioinformat- ics analyses indicated that all of th...From a specialized cDNA library, four novel box H/ACA snoRNAs, named GLsR22, GLsR23, GLsR24 and GLsR25, were identified from the primitive eukaryote, Giardia lamblia. Bioinformat- ics analyses indicated that all of them can be poten- tially folded into double hairpins, the typical secon- dary structures of box H/ACA snoRNAs. GLsR24 and GLsR25 are predicted to guide the site-specific pseudouridylation at U1753 and U2396 on 23S rRNA, respectively, while GLsR22 and GLsR23 belong to the family of “orphan” snoRNAs. All of the four novel snoRNAs are encoded by single copy genes and located in small intergenic regions. Interestingly, compared with the counterparts previously reported in Archaea and other unicellular protozoan, the box H/ACA snoRNAs identified from G. lamblia have unique structural features, implying that snoRNAs evolved from prokaryotes to eukaryotes in different ways.展开更多
植物通讯信号分子β-罗勒烯在植物防御方面起着重要作用,受β-罗勒烯诱导快速高表达的SFIBO(snoRNAs Fast-Induced by Ocimene)基因的启动子特性有待研究。SFIBO基因起始密码子上游有877 bp,依据这段序列上已知的元件分布特征,将877 bp...植物通讯信号分子β-罗勒烯在植物防御方面起着重要作用,受β-罗勒烯诱导快速高表达的SFIBO(snoRNAs Fast-Induced by Ocimene)基因的启动子特性有待研究。SFIBO基因起始密码子上游有877 bp,依据这段序列上已知的元件分布特征,将877 bp分成三段:-877~-1 bp、-637~-1 bp和-277~-1 bp。将这3个片段分别扩增后与GUS报告基因构建融合表达框,并利用浸花法将这3个植物双元表达载体转化拟南芥Col-0。对GUS组织化学染色进行分析,结果显示SFIBO基因的有效启动子为起始密码子上游637 bp DNA片段,β-罗勒烯诱导反应的顺式作用元件在-637~-277 bp之间的这360 bp DNA序列上。以上结果为下一步确定β-罗勒烯响应元件的具体序列和研究SFIBO基因的功能提供了科学依据。展开更多
基金supported in part by a grant from the National Cancer Institute,USA (No. R01CA085560)
文摘Deletion of chromosome 6q is frequent in breast cancer, and the deletion often involves a region in 6q 14-q 16. At present, however, the underlying tumor suppressor gene has not been established. Based on a recent study identifying snoRNA U50 as a candidate for the 6q14-16 tumor suppressor gene in prostate cancer, we investigated whether U50 is also involved in breast cancer. PCR-based approaches showed that U50 underwent frequent genomic deletion and transcriptional downregulation in cell lines derived from breast cancer. Mutation screening identified the same 2-bp deletion of U50 as in prostate cancer in both cell lines and primary tumors from breast cancer, and the deletion was both somatic and in germline. Genotyping of a cohort of breast cancer cases and controls for the mutation demonstrated that, while homozygous genotype of the mutation was rare, its heterozygous genotype occurred more frequently in women with breast cancer. Functionally, re-expression of U50 resulted in the inhibition of colony formation in breast cancer cell lines. These results suggest that noncoding snoRNA U50 plays a role in the development and/or progression of breast cancer.
文摘By constructing and screening the Schizosac-charomyces pombe nuclear cDNA library, a novel small nu-cleolar RNAs (snoRNA) was identified. The novel snoRNAdisplays structural features typical of C/D box snoRNA fam-ily and possesses a 10-nt-long rRNA antisense element whichis predicted to guide the 2’-O-methylation of the fission yeast 25S rRNA at G940. As expected, the rRNA ribose-methyla-tion site predicted by the novel snoRNA was preciselymapped by a deoxynucleoside triphosphate concentration-dependent primer extension assay. The comparison of func-tional element of guide snoRNAs among eukaryotes reveals that the novel snoRNA is a partial counterpart of the bud-ding yeast snR60 and was termed snR60-II. snR60-II genenested in the intron of a non-coding RNA gene with an un-known function, which is the first example of a yeastsnoRNA encoded in an intron of a non-coding RNA gene.Furthermore, a number of yeast snR60 homologues were also identified from other fungi and fly. Our results reveal thatsnR60 exhibits diverse genomic organization in eukaryotes, implying the high mobility of snR60 gene in the course ofevolution.
基金the National Natural Science Foundation of China （Grant Nos. 30230200 ＆ 30370328） the funds from the Ministry of Education of China and Natural Science Foundation of Guangdong Province （Grant No. IRT0447, NSF-05200303） the National Basic Research Program （Grant No. 2005CB724600）.
文摘From a specialized cDNA library, four novel box H/ACA snoRNAs, named GLsR22, GLsR23, GLsR24 and GLsR25, were identified from the primitive eukaryote, Giardia lamblia. Bioinformat- ics analyses indicated that all of them can be poten- tially folded into double hairpins, the typical secon- dary structures of box H/ACA snoRNAs. GLsR24 and GLsR25 are predicted to guide the site-specific pseudouridylation at U1753 and U2396 on 23S rRNA, respectively, while GLsR22 and GLsR23 belong to the family of “orphan” snoRNAs. All of the four novel snoRNAs are encoded by single copy genes and located in small intergenic regions. Interestingly, compared with the counterparts previously reported in Archaea and other unicellular protozoan, the box H/ACA snoRNAs identified from G. lamblia have unique structural features, implying that snoRNAs evolved from prokaryotes to eukaryotes in different ways.
文摘植物通讯信号分子β-罗勒烯在植物防御方面起着重要作用,受β-罗勒烯诱导快速高表达的SFIBO(snoRNAs Fast-Induced by Ocimene)基因的启动子特性有待研究。SFIBO基因起始密码子上游有877 bp,依据这段序列上已知的元件分布特征,将877 bp分成三段:-877~-1 bp、-637~-1 bp和-277~-1 bp。将这3个片段分别扩增后与GUS报告基因构建融合表达框,并利用浸花法将这3个植物双元表达载体转化拟南芥Col-0。对GUS组织化学染色进行分析,结果显示SFIBO基因的有效启动子为起始密码子上游637 bp DNA片段,β-罗勒烯诱导反应的顺式作用元件在-637~-277 bp之间的这360 bp DNA序列上。以上结果为下一步确定β-罗勒烯响应元件的具体序列和研究SFIBO基因的功能提供了科学依据。
