小鼠腭裂相关基因的克隆及基因表达的意义

目的：筛选外克隆正常组小鼠腭突与腭裂组小鼠腭突组织中差异表达的基因，探讨它们在腭裂发生过程中表达的意义。方法：建立C57BL／6N小吸腭裂模型，分别提取胚胎12d的正常组及维甲酸处理组小鼠腭突组织中的mRNA，利用PCR的改良消减杂交技术，筛选并克隆小鼠腭突正常发育时期与腭裂形成过程中差异表达的基因及测序。结果：共获得差异表达的基因40个，2个为新基因。结论：克隆的新基因及fau基因对能对腭突间充质细胞的生长、分化具有重要的调控作用。     

Smad2/3信号分子在小鼠胚胎腭发育和腭裂形成中的表达

背景：部分学者通过体外器官培养研究认为全反式维甲酸干扰了Smad2/3在腭部的表达,具体机制尚不明确。目的：观察腭突Smad2/3信号分子在胚鼠腭部发育及腭裂形成过程中的表达变化。方法：54只C57BL/6J近交系孕鼠随机分为3组,在妊娠10d,实验组一次性灌胃全反式维甲酸100mg/kg诱导胚鼠两侧腭突不能在中线融合,建立腭裂畸形动物模型;植物油对照组灌胃10mL/kg橄榄油,空白对照组不做处理。结果与结论：在植物油对照组中,从妊娠13d18时到妊娠14d18时腭间充质细胞中Smad2/3免疫阳性表达逐步增高,至妊娠15d8时表达开始出现下降,实验组也表现为这一变化趋势,且同一组间表达较植物油对照组明显;在腭中嵴上皮细胞中,植物油对照组随着腭突的融合,腭中嵴上皮带消失,Smad2/3表达也明显下降,实验组始终未融合,未见明显的Smad2/3阳性细胞。在整个胚腭正常发育和腭裂形成过程中,空白对照组与植物油对照组Smad2/3阳性细胞表达几乎无差异。提示过量全反式维甲酸可能通过干扰腭中嵴上皮细胞及间充质细胞中Smad2/3信号分子的表达,从而影响小鼠胚腭上皮间充质转化,与腭裂形成密切相关。     

高脂膳食及有氧运动对C57BL/6小鼠骨骼肌基因表达谱的影响

目的:运用基因芯片技术研究高脂膳食及有氧运动因素对C57BL/6小鼠骨骼肌基因表达谱的影响,初步探寻有氧运动改善机体胰岛素抵抗(IR)相关基因的机制。方法:选用C57BL/6雄性小鼠80只,随机分为正常饮食组和IR模型组,分别饲以基础和高脂饲料10周。鉴定高脂膳食组IR小鼠模型建立成功后,将正常饮食组随机分为正常饮食安静组(NC)和正常饮食运动组(NE),IR模型组分为高脂饮食安静组(HC)和高脂饮食运动组(HE)。运动方案采用强度为75%VO2max有氧跑台训练,持续6周。后分离各组小鼠股四头肌,提取总RNA,经荧光标记后进行芯片杂交,利用芯片扫描仪记录荧光信号,并通过相关软件对所得数据进行统计分析。结果:HC/NC共筛选差异表达基因136个;NE/NC筛选差异表达基因74个;筛选HE/HC差异表达基因29个;HE/NC差异表达基因共252个,其中170个基因(HE/NC-DF)的差异表达由高脂膳食和运动因素共同引起;HE/HC中16个基因为与HE/NC-DF共同差异基因。结论:高脂膳食及有氧运动对小鼠骨骼肌基因表达均有显著影响,本研究初步筛选出有氧运动改善IR潜在相关基因,为进一步研究有氧运动改善IR分子机制提供了理论依据。     

Tpap基因在小鼠睾丸中的表达

背景:精子发生过程受许多特异分子及细胞间作用的严格调节,包括染色体结构变化及一系列特定基因程序性表达调控.长期以来由于缺乏合适的体内和体外研究模型,精子发生分子机制的研究进展较慢,尤其缺乏对关键调节基因的认识.目的:筛选与精子发生相关的基因,并分析其表达特点.方法:将4,9,18,35,54 d和6月龄小鼠睾丸组织cDNA探针与Affymetrix全基因组芯片进行杂交,筛选出差异表达的基因.然后通过反转录-聚合酶链反应分析差异表达基因在小鼠睾丸不同发育阶段中的表达.结果与结论:对Affymetrix全基冈组芯片杂交结果分析后,筛选得到1个差异表达杂交点.通过在NCBI与小鼠全基因组序列Blast分析可知该差异表达基因是Tpap基因.该基因在4,9,18,35,54d和6月龄小鼠睾丸中杂交信号校正值分别是4.4(A)、12.9(A),262.4(P)、1 136.7(P)、1 617.5(P)和1 128(P),表明4,9 d小鼠睾丸中该基因无表达,18 d小鼠开始表达,RT-PCR结果表明小鼠Tpap基因在小鼠9 d及之前的睾丸中没有表达,在18 d睾丸后开始表达,与基因芯片分析相一致.结果表明,Tp印基因为小鼠年龄依赖性表达基因,小鼠Tpap的表达与小鼠精子发生的过程有很强的一致性,推测该基因在哺乳动物精子发生中起重要作用.     

新基因TSC43在小鼠和人睾丸组织中的表达分析

目的筛选与精子发生相关的睾丸特异性新基因。方法将不同发育阶段的小鼠睾丸组织cDNA探针与Affymetiix全基因组芯片进行杂交，通过杂交信号的比较，筛选出差异表达的基因。用生物学信息软件对该基因进行生物学信息分析。RT-PCR分析该基因在小鼠不同发育阶段睾丸、小鼠不同组织及人不同组织中的表达。结果通过4、9、18、35、54日龄和6月龄小鼠睾丸的芯片信号比较筛选出一个差异表达基因（GenBank登录号：XM_156106），全长有1364bp，含有1146bp的完整ORF，编码一个有381个氨基酸、分子量为43．578kDa的蛋白质，我们将其命名为TSCA3。亚细胞定位预测显示TSCA3基因可能在细胞核中表达。EBI功能域分析表示该基因可能参与了cAMP依赖的PK（Protein kinase）的锚定。RT-PCR分析表明TSCA3基因特异性表达于小鼠睾丸组织中且具有时序性表达。TSCA3蛋白在人的同源基因GenBank登录号为NM-152539，在381个氨基酸区域内有49％的同源性，人TSC43（hTSC43）基因特异性地表达于人睾丸组织中。结论TSCA3基因的表达与小鼠精子发生的过程一致，在小鼠及人的睾丸组织中特异性表达，显示其可能在精子发生中起着重要作用。     

ATP/GTP结合蛋白1基因在胃癌及食管癌组织中高表达

目的:应用荧光mRNA差异显示技术(DD-PCR),筛选胃癌及食管癌相关基因的异常表达。方法:收集临床胃癌组织样本,通过荧光差异显示技术(DD-PCR)获得胃癌样品中差异的片段,对这些片段进行克隆和测序。通过在GenBank中同源性检索,查找与差异片段相对应的同源基因。利用半定量PCR及定量PCR方法检验该基因在胃癌及食管癌组织中与其对应正常组织之间表达的差异。结果:通过DD-PCR获得的一个差异表达片段的序列对应于ATP/GTP结合蛋白1基因(A/GT-PBP1)。半定量PCR及荧光定量PCR技术检测结果表明,A/GTPBP1基因在胃癌及食管癌组织中的表达量高于其对应的正常组织(胃癌,P<0.01;食管癌,P<0.01)。该基因包含25个外显子,读码框长3561bp,编码1186个氨基酸,蛋白质相似性分析表明该蛋白为G蛋白家族成员。结论:A/GTPBP1在胃癌组织中异常表达,可能在胃癌发生过程中起调节作用。     

铁死亡相关lncRNA结肠癌预后风险模型的构建及临床应用

目的 基于肿瘤基因图谱计划(TCGA)数据库筛选铁死亡相关长链非编码RNA(lncRNA),建立结肠癌预后风险模型,并探讨其临床应用价值。方法 选取行结肠癌根治术的患者48例,收集术中切除的癌组织及对应的癌旁组织(距离癌组织边缘2～3 cm)。从TCGA数据库中收集结肠癌的转录组数据(结肠癌组织428例、正常结肠组织41例)及对应患者的临床资料。筛选结肠癌组织与正常结肠组织差异表达的铁死亡相关基因,并进行基因本体(GO)富集分析和京都基因与基因组数据库(KEGG)通路分析。筛选与结肠癌预后相关的铁死亡lncRNA,采用共识聚类分析对结肠癌患者进行分组,并比较总体生存率。采用LASSO-Cox回归分析建立预后风险模型。建立用于预测结肠癌患者总体生存率的列线图。采用细胞学实验分析关键lncRNAITGB1-DT在结肠癌中的生物学功能。结果 从TCGA数据库中筛选出72个差异表达的铁死亡相关基因,其中表达上调47个、表达下调25个,GO和KEGG通路分析结果显示这72个基因广泛参与了铁代谢和脂肪酸氧化等生物学过程。共筛选出20个结肠癌组织与正常组织有差异的铁死亡lncRNA。根据共识聚类分析...     

新基因TSC21的生物信息学分析及其原核载体构建表达

目的用生物信息学分析新基因TSC21并进行蛋白表达及纯化。方法将不同发育阶段的小鼠睾丸组织cDNA探针与Affymetrix金基因组芯片进行杂交并筛选出差异表达的基因。用生物学信息软件对该基因进行生物学信息分析。运用RT-PCR分析该基因小鼠不同组织及人不同组织中的表达。对人的TSC21基因进行cDNA克隆、蛋白表达及纯化。结果通过不同日龄小鼠睾丸的芯片信号比较筛选出一个差异表达基因（GenBank登录号：NM_028825），金长有810bp，含有543bp的完整ORF，编码一个有180个氨基酸、分子量为21．040kDa的蛋白质，我们将其命名为TSC21。亚细胞定位预测显示TSC21基因可能在细胞核中表达。基因功能域预测表明在氨基酸34-40处有CK1和CK2磷酸化位点，在氨基酸100-106处有PKA（cAMP-dependent protein kinase A）磷酸化位点。RT-PCR分析表明TSC21基因特异性表达于小鼠睾丸组织。TSC21蛋白在人的同源基因GenBank登录号为NM-152670，在180个氨基酸区域内有82％的同源性，人TSC21（hTSC21）基因特异性地表达于人睾丸组织中。成功构建PET-28a2c（＋）vector／hTSC21表达载体,并转化B121，以IPTG诱导蛋白表达，对诱导剂浓度、诱导时间进行优化后以镍离子亲和层析纯化目的蛋白。结论TSC21基因在小鼠及人的睾丸组织中特异性表达并具有高度同源性，显示其可能在精于发生中起着重要作用。所得人TSC21蛋白可进行其蛋白结构活性、睾丸组织中的定位分布及在男性不育等疾病检测的研究。     

腭裂术中保留腭小神经的手术配合

腭裂是口腔颌面整形外科最常见的畸形之一.整复腭裂的目的:一是创造良好的"腭咽功能",为实现腭裂术后语音的正常提供条件;二是恢复腭部的正常解剖关系,封闭腭部的裂隙,使口腔与鼻腔分开;三是恢复腭部的生理功能.如何尽可能地保留各解剖部位的组织结构并将其恢复到正常状态,是实施腭裂修复手术过程中始终需要考虑的问题[1].     

结肠癌组织中差异表达基因的筛选和鉴定

目的 筛选和克隆结肠癌和正常结肠组织差异表达的基因片段,为探讨结肠癌的发病机制提供线索。方法 应用基因差异显示技术（DD—PCR）,比较结肠癌和正常结肠组织基因表达的差异,对其中一条有明显差异的基因片段进行克隆、测序,测序结果提交GenBank数据库中进行同源性分析,并用半定量RT—PCR进行初步鉴定。结果 同源性分析表明,该片段与已知基因DDX32高度同源（99％）。RT—PCR结果显示,在结肠癌组织中该基因mRNA的表达水平显著高于正常结肠组织（P〈0．05）。结论 DD—PCR是筛选差异表达基因的有效手段;在结肠癌组织中DDX32基因的表达显著高于正常结肠组织,此结果为研究DDX32基因在结肠癌发病中的作用提供了线索。     

Polymorphism of the ovine calpastatin gene

Calpastatin is a specific inhibitor of calpains and has been implicated in the regulation of beef tenderization. Variation in the ovine calpastatin gene (CAST) was investigated by amplification of a fragment containing the entire exon 6 using polymerase chain reaction (PCR), followed by single-strand conformational polymorphism (PCR-SSCP) analysis and DNA sequencing. Five novel SSCP patterns, representing five different sequences, were identified. Either one or two different sequences were detected in individual sheep and all the sequences identified shared high homology to the published ovine and bovine CAST sequences, suggesting that these sequences represent allelic variants of the ovine CAST gene. Sequence analysis revealed a non-synonymous amino acid variation in exon 6, which would result in a Gln/Leu substitution in Domain L of the mature protein. Considerable variation was detected in an intron region close to the acceptor splice site, with both sequence variation and length variation being observed in this region. Variation detected here might have an impact on both the function and expression of ovine calpastatin.     

Mutations in the ligand-binding domain of the androgen receptor gene cluster in two regions of the gene.

We have analyzed the nucleotide sequence of the androgen receptor from 22 unrelated subjects with substitution mutations of the hormone-binding domain. Eleven had the phenotype of complete testicular feminization, four had incomplete testicular feminization, and seven had Reifenstein syndrome. The underlying functional defect in cultured skin fibroblasts included individuals with absent, qualitative, or quantitative defects in ligand binding. 19 of the 21 substitution mutations (90%) cluster in two regions that account for approximately 35% of the hormone-binding domain, namely, between amino acids 726 and 772 and between amino acids 826 and 864. The fact that one of these regions is homologous to a region of the human thyroid hormone receptor (hTR-beta) which is a known cluster site for mutations that cause thyroid hormone resistance implies that this localization of mutations is not a coincidence. These regions of the androgen receptor may be of particular importance for the formation and function of the hormone-receptor complex.     

The future of Duchenne muscular dystrophy gene therapy: shrinking the dystrophin gene

Duchenne muscular dystrophy is a debilitating muscle-wasting disease caused by mutations in the dystrophin gene - one of the largest genes identified thus far - and which ultimately results in premature death. With no current treatment available, the hopes of many sufferers lie in the establishment of an effective gene therapy. The adeno-associated virus is now emerging as a premium gene transfer vector eliciting minimal immune response from the host and allowing for long-term gene expression. It is the scope of this review to examine the recent efforts that have been made to develop ultra-truncated versions of the dystrophin gene that retain functionality, yet can still be cloned into recombinant adeno-associated viral vectors and other low-capacity vector systems.     

A novel telomerase-specific gene therapy: gene transfer of caspase-8 utilizing the human telomerase catalytic subunit gene promoter

Apoptosis is a genetically encoded cell death process and is a pathway that may be disrupted in tumor cells. Therefore, therapies that restore the ability to undergo apoptosis are promising for the treatment of tumor cells. We have demonstrated that the transfer of apoptosis-inducible genes inhibits the growth of tumors in vitro and in vivo through induction of apoptosis. However, to restrict induction of apoptosis to tumor cells, we need to explore a tumor-specific expression system of these genes. In the present study, we developed the telomerase-specific transfer system of apoptosis-inducible genes, utilizing the promoter of the human telomerase catalytic subunit (hTERT) gene. Approximately 90% of tumors have telomerase activity whereas most normal cells do not express the activity. These observations indicate that telomerase is a particularly attractive target for the tumor-specific expression system of vectors. We demonstrate here that by using the hTERT promoter-driven caspase-8 expression vector (hTERT/caspase-8), apoptosis is restricted to telomerase-positive tumor cells of wide range, and is not seen in normal fibroblast cells without telomerase activity. Furthermore, treatment of subcutaneous tumors in nude mice with the hTERT/caspase-8 construct inhibited tumor growth significantly because of induction of apoptosis (p < 0.01). The telomerase-specific expression of apoptosis-inducible genes afforded by the hTERT promoter, therefore, may be a novel and promising targeting approach for the treatment of tumors with telomerase activity.     

Recombinant AAV-mediated gene transfer to the retina: gene therapy perspectives

Retinal degenerative diseases such as retinal macular degeneration and retinitis pigmentosa constitute a broad group of diseases that all share one critical feature, the progressive apoptotic loss of cells in the retina. There is currently no effective treatment available by which the course of these disorders can be modified, and visual dysfunction often progresses to total blindness. Gene therapy represents an attractive approach to treating retinal degeneration because the eye is easily accessible and allows local application of therapeutic vectors with reduced risk of systemic effects. Furthermore, transgene expression within the retina and effects of treatments may be monitored by a variety of noninvasive examinations. An increasing number of strategies for molecular treatment of retinal disease rely on recombinant adeno-associated virus (rAAV) as a therapeutic gene delivery vector. Before rAAV-mediated gene therapy for retinal degeneration becomes a reality, there are a number of important requirements that include: (1) evaluation of different rAAV serotypes, (2) screening of vectors in large animals in order to ensure that they mediate safe and long-term gene expression, (3) appropriate regulation of therapeutic gene expression, (4) evaluation of vectors carrying a therapeutic gene in relevant animal models, (5) identification of suitable patients, and finally (6) manufacture of clinical grade vector. All these steps towards gene therapy are still being explored. Outcomes of these studies will be discussed in the order in which they occur, from vector studies to preclinical assessment of the therapeutic potential of rAAV in animal models of retinal degeneration.