新的人羧肽酶A抑制物cDNA的克隆、定位和表达谱分析

从人的胎脑cDNA文库中,克隆到一条全新的人类羧肽酶A抑制物基因,此cDNA序列全长1049bp,包括翻译起始位点附近的Kozak序列,669bp 的开放读框以及3端的加尾信号,共编码222个氨基酸,它编码的蛋白与小鼠Latexin蛋白和大鼠Latexin蛋白分别有高达85％和84％的同源性,因此命名为人类LATEXIN基因,应用辐射杂交方法,将该基因伫位在人3号染色体3q24区段,位于分子标记D3S1605和D3S1553之间,采用基因芯片杂交的方法研究其在某些组织或细胞中的表达情况,发现在前列腺癌中表达量较高。     

人原肌球蛋白结合蛋白3(TMOD3)cDNA的克隆及功能初步分析

从人的胎脑cDNA文库到中克隆到1条人原肌球蛋白结合蛋白3（TMOD3）基因,该基因cDNA序列长1402bp,可以编码352个氨基酸残基组成的蛋白,与大鼠,果蝇和线虫的原肌球结合蛋白同源性分别为82％,41％和35％,TMOD3基因定位在人15q21.1-q21.2,位于遗传位标D15S146和D15S117之间,采用基因芯片杂交的方法研究其表达谱概况,发现该基因在多种,组织和细胞中均表达。     

人类磷酸泛酰巯基乙胺结合蛋白新基因的分离和鉴定

在对AD293和HEK293进行差减杂交以探索两者在吸附和凋亡特性上的差异时,从AD293的高表达文库中分离得到一段新的cDNA片段.从人类胎脑文库克隆得到该基因,全长2 745 bp,编码的蛋白含518个氨基酸,被预测为磷酸泛酰巯基乙胺结合蛋白.该基因在染色体上定位于2p22.3,包含8个外显子.该cDNA编码的蛋白序列含有一个凋亡抑制蛋白5结构域,外皮蛋白重复片段和铜结合辛肽重复片段.RT-PCR分析显示该基因在人类正常组织和癌组织中广泛表达,但在癌组织中表达量相对较低,提示其可能对细胞凋亡有抑制作用.该基因在进化过程中高度保守.     

人新的PLP基因全长cDNA的克隆与分析

在批量分离与脑发育相关的基因克隆时,从人3个月胎脑cDNA文库中得到一全长2261bp的cDNA克隆.其开放性阅读框架编码一个含有551个氨基酸残基的蛋白质,此蛋白与一种推测的细胞结构调节蛋白parelemmin同源,故命名为PLP(paralemmin-like protein).GenBank接受号为AF132731.Northern杂交显示该基因只有一个转录本,大小与获得的该克隆吻合.组织表达谱分析发现该基因在成人心脏、骨骼肌中的表达量高于其他组织.     

人酪蛋白激酶CK1γ1 cDNA的克隆、染色体定位和组织表达谱分析

从人胎脑cDNA文库中克隆到一种新的酪蛋白激酶的cDNA，全长1754dp，拟编码438个氨基酸残基，该蛋白预测的分子质量为50272u，等电点9．37，经同源分析，该基因在大鼠的CK1γ1蛋白有94％的相似性，为人1型酪蛋白激酶－γ1亚型基因，人CK1γ1基因同时与15号与17号染色体的基因组部分序列完全一致，但RH法却将基因定位于15q22区段的D15S159－D15S125 Marker之间，多组织Northern膜（MTN）杂交分析显示，人CK1γ1基因在肝，结肠，肾和骨骼肌特别在肝组织中有高表达。     

人SVOP基因的cDNA克隆及表达

SV2和SVOP都是大鼠中包含有12个跨膜结构域的突触小泡蛋白.笔者从人类大脑的cDNA文库中分离得到了一个类似于大鼠突触小泡蛋白SV2和SVOP的人类新基因的全长cDNA序列,它包含一个含有1 646个核苷酸的开放阅读框,编码一个含548个氨基酸的蛋白质.生物信息学分析表明:该基因定位在第12号染色体的12q24.12区域.Northern杂交结果表明:该基因只在人类大脑组织中表达,且与无脊椎动物线虫、疟蚊和果蝇的同源基因有50%的氨基酸同源性,与脊椎动物大鼠和小鼠的同源基因有90%以上的氨基酸同源性.     

RBM13 cDNA的克隆及其表达谱分析

从人胎脑cDNA文库中克隆到一条长3479bp的cDNA,它含一个长903bp的开放阅读框架,拟编码一个300个氨基酸的蛋白质,其分子质量为35397u,等电点为5．35,与酵母MAK16蛋白的同源性为41％,该编码蛋白有一个双侧核定位信号motif和一个RNA结合motif,将这一新cDNA序列推导的蛋白命名为RNA结合基序蛋白13（RBM13）,基因定名为RBM13,用RBM13基因的cDNA探针进行Northern杂交,检测到3．6kb和2．2kb二种长度的转录本。在心脏,骨骼肌,肾脏和肝脏中有较高表达。     

一条新的人类组氨酰tRNA合成酶类似物全长cDNA的克隆及表达谱分析

从人胎脑文库中克隆到一条长为 12 19bp的cDNA ,它编码 2 3.4ku的肽链 .该肽链与葡萄球菌组氨酰tRNA合成酶N端同源 5 8% .利用humangenomicblast可将其定位于 2 0p11.Northern杂交显示胎脑中有一约1.5kb的单一条带 .基因芯片杂交分析表明 ,其在肺癌和前列腺癌组织中表达较高 .绿荧光蛋白亚细胞定位技术显示该蛋白存在于COS7细胞的细胞质中     

食管癌表达上调基因EC45 cDNA的克隆

鉴别食管癌中差异表达的基因.利用抑制削减杂交和反式Northern高密度点杂交相结合的方法,获得一个在70%(18/26)食管癌中表达显著上调的基因,命名为EC45.通过放射杂交技术将其定位于3p12-3p11.2.通过筛选食管癌cDNA文库获得全长EC45cDNA(1987bp).EC45编码204个氨基酸,与核糖体蛋白l15的开放阅读框100%同源,但与5'非翻译区和3'非翻译区均无同源性.16种正常成人组织Northern杂交显示EC45均有表达,其转录本大小为2.0kb.以上结果提示:编码核糖体蛋白L15的EC45基因在食管癌组织中表达上调,在食管癌发生发展过程中可能发挥作用.     

人类抗砷相关基因hARRG全长cDNA的克隆和在E.coli中表达

通过对构建的人胎脑cDNA文库进行大规模测序,发现一条人类新基因,序列与仓鼠asr2序列高度同源,达88％,命名为人类抗砷相关基因（human arsenic resistance related gene.hARRG),hARRG与抗砷基因相关序列ARS2（AF082871）几乎完全全同源,仅比它短253bp,hARRG并不是全长基因而仅是一个cDNA片段,为了获得hARRG全长cDNA,运用Northern blot电子RACE和5－SMART－RACE的方法克隆了一条2999bp 的hARRG全长cDNA,通过Unigene染色体定位于7q21.3,经过生物信息学分析发现,该cDNA有完整的读码框,编码一个788个氨基酸的蛋白,预计分子质量为89．2ku,并在大肠杆菌中获得了成功表达。     

一个新C2H2型锌指蛋白的功能的初步研究

通过筛选人18周胎脑cDNA文库,得到一条编码332AA的全长新基因,生物信息学研究表明,该蛋白质序列有2个C2H2型锌指结构,其中1个锌指结构有RNA－binding蛋白特异锌指的特征,虽然同源比较发现与多种蛋白质精氨酸N端转甲基酶（protein arginine N-methyltransferase) 有一定的同源性,但新锌指蛋白不含转甲基酶的活性功能区域,属功能未知的基因,利用芯片研究功能未知基因的表达是一种较好的手段,通过代谢增强剂PMA（phorbol myristae acetate)刺激培养的血管内皮细胞,观察细胞受激活后新锌指蛋白基因的表达变化,结果表明新基因表达量提高了11倍以上,证实新基因属内皮细胞的极早期应答基因（Immediate early response gene,ERG)。     

一条在人睾丸中高表达的新的环指蛋白(RNF20)

从人胎脑构建的cDNA文库中,通过大规模测序筛选的方法获得一条新基因,该基因蛋白序列含有1个环指（RING finger)基序及2个进核信号（nuclear localization signal NLS)序列,钭此基因命名为RNF20（RING Finger 20),用放射杂交细胞系（Radial hybrid RH)方法定位此基因在人染色体的9q22上,Northern杂交表明,其mRNA在睾丸组织中高表达,用小鼠睾丸做原位杂交表明,小鼠的同源基因在精原细胞及初级精母细胞中高表达,未成年小鼠睾丸中的精原细胞没有发达,提示RNF20可能参与精子发生的调控作用。     

Cloning of a novel gene encoding human thioredoxin-like protein

mRNA differential display (DDRT-PCR) has been used to analyze different human fetal brain tissues of different developmental stages (13- and 33-week). According to the sequence of one EST obtained in this assay, a pair of primers have been designed to screen the arrayed human fetal brain cDNA library. A1 .2-kb cDNA clone has been found. This cDNA consists of an 867 bp open reading frame, a 132 bp 5' untranslated sequence and a 209 bp 3' untranslated sequence with a typical polyadenylation signal. The coding region predicts a protein of 289 amino acids. Its N-terminal of 105 residues is highly homologous to human thioredoxin, while no homology has been found in the databases with its C-terminal of 184 residues. Its N-terminal region also contains the conserved active site sequence CGPC (Cys-Gly-Pro-Cys) of thioredoxin. It was named human Thioredoxin-like gene (hTRXL).     

Nucleotide sequence of cloned cDNA of human c-myc oncogene

Like other transforming genes of retroviruses, the v-myc gene of the avian virus, MC29, has a homologue in the genome of normal eukaryotic cells. The human cellular homologue, c-myc, located on human chromosome 8, region q24 leads to qter (refs 1, 2), is translocated into the immunoglobulin heavy-chain locus on human chromosome 14 (ref. 3) in Burkitt's lymphoma, suggesting that c-myc has a primary role in transformation of some human haematopoietic cells. In addition, c-myc is amplified in the human promyelocytic leukaemia cell line, HL60 (refs 6, 7) which also contains high levels of c-myc mRNA. Recently, Colby et al. reported the nucleotide sequence of the human c-myc DNA isolated from a genomic recombinant DNA library derived from human fetal liver. This 4,053-base pair (bp) sequence includes two exons and one intron of the myc gene, and the authors have suggested the existence of a human c-myc mRNA of 2,291 nucleotides that has a coding capacity for a protein of molecular weight (Mr) 48,812. We have approached the problem of accurately defining the characteristics of the human c-myc mRNA and c-myc protein by determining the sequence of the c-myc cDNA isolated from a cDNA library prepared from mRNA of a clone of the K562 human leukaemic cell line. K562 cells are known to contain c-myc mRNA which is similar in size to the c-myc mRNA of other human cell types. We report here the sequence of 2,121 nucleotides of a human c-myc mRNA and demonstrate that its 5' noncoding sequence does not correspond to the sequence of the reported genomic human sequence. However, our data confirm that the intact human c-myc mRNA can encode a 48,812-Mr protein with a sequence identical to that reported by Colby et al.     

Cloning, prokaryotic expression,purification and sequence analysis of 20S proteasome subunit gene from T.harzianum

The gene encoding the 20S proteasome subunit（PR29） was cloned from cDNA library of Trichoderma harzianum and expressed in Escherichia coli BL21 （D3） using a pET-28a expression system. The molecular weight of the protein was found to be approximately 29 kDa, as estimated by SDS-PAGE on gels. The target protein was insoluble when induced at 22℃ with 0.4 mmol/L IPTG, while dissoluble if induced at 37℃ with 0.8mmoL/L IPTG. The expressed product was purified through Ni-magnetic beads His Bind. The purity of the fusion protein reached above 80%. The entire eDNA sequence consisted of 1094 bp with 173 and 135 bp in 5＇ and 3＇ untranslated regions respectively. The gene encoding 261 amino acids has no signal peptide sequence. These results could provide a basis for validating the func-tions of PR29. It also provided a preliminary indication for further study of the mechanism and function of proteasome, and more information of proteasome mechanism in T.harzianum could be obtained.     

人类超氧化物歧化酶在酿酒酵母系统中的高效表达

超氧化物歧化酶(SOD)是一种在生物界广泛存在的抗氧化酶,在抗衰老、抗肿瘤、抗免疫疾病和电磁辐射上都起着重要的作用．对一从人类胎肝cDNA文库中筛到的SOD基因片段进行重组、克隆,并得到带有启动子PADHZ—GAPDH和终止子TADHI的高效稳定的酿酒酵母表达载体pHC11-hSOD．转化酿酒酵母DCO4后获得工程菌DCO4／pHC11-hSOD．表达产物经破壁后SDS-PAGE电泳检测为20ku的条带;酶活性测定结果表明发酵液有40万U／L的hSOD活性．此外,还研究了工程菌的发酵条件和hSOD产物的纯化方法．纯化产物在SDS-PAGE上和Superdex分子筛检测显示,所得产物的纯度已达95％以上．