Chromosomes in human-mouse and human-(human-mouse)hybridomas wereanalysed by G-banding methods.It was found that most human chromosomes,exceptNo.13 and X,Y,were retained.The frequencies of chromosomes No.1,3,4,5,6,17,...Chromosomes in human-mouse and human-(human-mouse)hybridomas wereanalysed by G-banding methods.It was found that most human chromosomes,exceptNo.13 and X,Y,were retained.The frequencies of chromosomes No.1,3,4,5,6,17,19,21 and 22 were higher than those of other chromosomes in each hybridoma clone.The myeloma cell lines X63-Ag8.653 and SHM-D33 were also analysed.The morphologyof marker chromosomes was apparently different between hybridomas.There were 7 kindsof marker chromosomes in human-mouse hybridomas and 16 kinds of markerchromosomes in human-(human-mouse)hybridomas.Clones that retained humanchromosome No.1 were more stable and clones that did not retain human chromosomeNo.14 were still capable of secreting human immunoglobulin.Clones that retained humanchromosome No.2 did not secret human k light chain McAb while clones that retainedhuman chromosomes No.2 and No.22 only secreted λ light chain.展开更多
OBJECTIVE: To investigate the loss of heterozygosity (LOH) on chromosomal arms 13q and 14q in nasopharyngeal carcinoma (NPC) using 21 microsatellite polymorphic markers and to study whether there is a correlation betw...OBJECTIVE: To investigate the loss of heterozygosity (LOH) on chromosomal arms 13q and 14q in nasopharyngeal carcinoma (NPC) using 21 microsatellite polymorphic markers and to study whether there is a correlation between LOH and clinicopathologic parameters and/or Epstein-Barr virus (EBV) infection in NPC. METHODS: Sixty cases of NPC were studied using polymerase chain reaction based microsatellite analysis with genescan and genotyping techniques. RESULTS: LOH was detected on 13q in 78% of NPC tumors, high frequency LOH loci (more than 30%) clustered to 13q12.3-q14.3 and 13q32. On chromosome 14q, LOH was detected in 80% of NPC tumors; high frequency LOH loci clustered to 14q11-q13, 14q21-q24 and 14q32. High frequency LOH at 13q31-q32 correlated with a lower level of EBV infection; LOH on chromosome 14q was closely associated with poor differentiation of NPC tumor cells. CONCLUSION: Our results suggest that in NPC, LOH on chromosome 13q and 14q are common genetic events, and putative tumor suppressor genes (TSG) residing in these regions may be involved in tumorigenesis.展开更多
Oxidation and reduction of some amino acids are one of the molecular mechanisms for regulating the function of proteins. The oxidation of methionine (Met) to methionine sulfoxide (Met(O)) results in decreasing or loss...Oxidation and reduction of some amino acids are one of the molecular mechanisms for regulating the function of proteins. The oxidation of methionine (Met) to methionine sulfoxide (Met(O)) results in decreasing or loss of the biological activity of related proteins. It was found that peptide methionine sulfoxide reductase (msrA) can reduce Met(O) to Met and therefore restored the biological function of the oxidized proteins. To reveal the methionine oxidation-reduction mechanism in human body, in this study, the cDNA sequence of bovine msrA was used as an information-probe to screen the human EST database. Based on a contig assembled from homologous ESTs, a 1 256-bp human MSRA cDNA was cloned from several human cDNA libraries. The cDNA contains an open reading frame (ORF) of 705 bp in length, which encodes 235 amino acid residues. Homology comparison revealed that human MSRA shares 88% and 61% identities with bovine and Escherichia coli msrA protein respectively. Expression pattern analysis revealed a展开更多
目的:抑癌基因的杂合缺失(loss of heterozygosity,LOH)被认为是结直肠癌形成的关键步骤之一。本实验研究了结直肠癌1号染色体短臂杂合的缺失情况,并探讨其临床意义。方法:选取11个微卫星DNA标记与83例结直肠癌病例的肿瘤和正常组织进行...目的:抑癌基因的杂合缺失(loss of heterozygosity,LOH)被认为是结直肠癌形成的关键步骤之一。本实验研究了结直肠癌1号染色体短臂杂合的缺失情况,并探讨其临床意义。方法:选取11个微卫星DNA标记与83例结直肠癌病例的肿瘤和正常组织进行PCR。PCR产物在ABIPrism377自动荧光测序仪上进行电泳,以GeneScan3.1和Genotyper2.1软件进行遗传位点扫描以及杂合缺失分析。结果:1号染色体短臂的平均杂合缺失率为18.00%,D1S468(1p36.33-36.31)位点的杂合缺失率最高,达36.54%。D1S2726位点的杂合缺失现象主要存在于直肠癌,缺失率为28.57%(6/21),而结肠癌的缺失率为0.00%(0/33),二者差异具统计学意义(P=0.002)。结论:在1号染色体短臂上可能存在与结直肠癌发生相关的抑癌基因,位于1p36.33-36.31这个区域。展开更多
文摘Chromosomes in human-mouse and human-(human-mouse)hybridomas wereanalysed by G-banding methods.It was found that most human chromosomes,exceptNo.13 and X,Y,were retained.The frequencies of chromosomes No.1,3,4,5,6,17,19,21 and 22 were higher than those of other chromosomes in each hybridoma clone.The myeloma cell lines X63-Ag8.653 and SHM-D33 were also analysed.The morphologyof marker chromosomes was apparently different between hybridomas.There were 7 kindsof marker chromosomes in human-mouse hybridomas and 16 kinds of markerchromosomes in human-(human-mouse)hybridomas.Clones that retained humanchromosome No.1 were more stable and clones that did not retain human chromosomeNo.14 were still capable of secreting human immunoglobulin.Clones that retained humanchromosome No.2 did not secret human k light chain McAb while clones that retainedhuman chromosomes No.2 and No.22 only secreted λ light chain.
文摘OBJECTIVE: To investigate the loss of heterozygosity (LOH) on chromosomal arms 13q and 14q in nasopharyngeal carcinoma (NPC) using 21 microsatellite polymorphic markers and to study whether there is a correlation between LOH and clinicopathologic parameters and/or Epstein-Barr virus (EBV) infection in NPC. METHODS: Sixty cases of NPC were studied using polymerase chain reaction based microsatellite analysis with genescan and genotyping techniques. RESULTS: LOH was detected on 13q in 78% of NPC tumors, high frequency LOH loci (more than 30%) clustered to 13q12.3-q14.3 and 13q32. On chromosome 14q, LOH was detected in 80% of NPC tumors; high frequency LOH loci clustered to 14q11-q13, 14q21-q24 and 14q32. High frequency LOH at 13q31-q32 correlated with a lower level of EBV infection; LOH on chromosome 14q was closely associated with poor differentiation of NPC tumor cells. CONCLUSION: Our results suggest that in NPC, LOH on chromosome 13q and 14q are common genetic events, and putative tumor suppressor genes (TSG) residing in these regions may be involved in tumorigenesis.
文摘Oxidation and reduction of some amino acids are one of the molecular mechanisms for regulating the function of proteins. The oxidation of methionine (Met) to methionine sulfoxide (Met(O)) results in decreasing or loss of the biological activity of related proteins. It was found that peptide methionine sulfoxide reductase (msrA) can reduce Met(O) to Met and therefore restored the biological function of the oxidized proteins. To reveal the methionine oxidation-reduction mechanism in human body, in this study, the cDNA sequence of bovine msrA was used as an information-probe to screen the human EST database. Based on a contig assembled from homologous ESTs, a 1 256-bp human MSRA cDNA was cloned from several human cDNA libraries. The cDNA contains an open reading frame (ORF) of 705 bp in length, which encodes 235 amino acid residues. Homology comparison revealed that human MSRA shares 88% and 61% identities with bovine and Escherichia coli msrA protein respectively. Expression pattern analysis revealed a
基金Supported by the National Natural Science Foundation of China (30170394) the Special Fund for Promotion of Education Ministry of Science P.R.C (985) and "973"Foundation of China (001cb51010201).
文摘目的:抑癌基因的杂合缺失(loss of heterozygosity,LOH)被认为是结直肠癌形成的关键步骤之一。本实验研究了结直肠癌1号染色体短臂杂合的缺失情况,并探讨其临床意义。方法:选取11个微卫星DNA标记与83例结直肠癌病例的肿瘤和正常组织进行PCR。PCR产物在ABIPrism377自动荧光测序仪上进行电泳,以GeneScan3.1和Genotyper2.1软件进行遗传位点扫描以及杂合缺失分析。结果:1号染色体短臂的平均杂合缺失率为18.00%,D1S468(1p36.33-36.31)位点的杂合缺失率最高,达36.54%。D1S2726位点的杂合缺失现象主要存在于直肠癌,缺失率为28.57%(6/21),而结肠癌的缺失率为0.00%(0/33),二者差异具统计学意义(P=0.002)。结论:在1号染色体短臂上可能存在与结直肠癌发生相关的抑癌基因,位于1p36.33-36.31这个区域。
