牦牛CAPN2基因的电子克隆及生物信息学分析

目的:对牦牛CAPN2基因进行电子克隆和序列分析,以期为进一步研究牦牛该基因与其肉质性状相关性以及基因结构和表达奠定理论基础。方法:利用人的CAPNA2基因cDNA序列为探针,在EST数据库进行同源性筛选,运用CAP3进行拼接得到完整序列并结合生物信息学进行序列分析。结果:牦牛CAPN2基因全长3 200bp,包含一个2 103bp的开放阅读框,共编码700个氨基酸;牦牛CAPN2的核苷酸序列与普通牛、羊、马、猪、小鼠、鸡、人相应序列间的一致性分别为99%、97%、90%、87%、85%、79%、90%。经聚类分析,牦牛首先与普通牛聚在一起,然后与羊、猪聚为一类;人与小鼠聚为一类;这两类相聚为一大类后,再依次与马、鸡相聚,其结果与以往的生物学分类结果一致。牦牛CAPN2基因编码蛋白的分子式为C3569H5503N255O1082S26,相对分子质量为79 935.2,理论等电点PI为4.86。结论:牦牛与普通牛、羊、马、猪、小鼠、鸡、人在CAPN2基因的编码序列具有较高有一致性。该基因编码的蛋白为位于细胞质中的水溶性蛋白。     

牦牛ZP3基因的克隆及蛋白质结构的预测

本研究对牦牛ZP3基因的编码区进行了克隆,在此基础上对ZP3蛋白的分子结构预测,为研究牦牛受精生物学提供基础。根据GenBank中普通牛的ZP3核苷酸序列设计特异性引物,以牦牛卵巢组织总RNA为模板,通过RT-PCR技术扩增牦牛ZP3基因cDNA序列(GenBank登录号为GQ856646),利用DNAMAN生物软件进行核苷酸和氨基酸序列分析、蛋白质专家系统ExPASy进行ZP3蛋白质分子结构预测。结果表明,扩增出的牦牛ZP3基因编码序列长1 266 bp,编码421个氨基酸。牦牛与牛、猪、狗、人、鼠和鸡ZP3基因核苷酸相应序列的同源性分别为98.42%、96.73%、79.67%、78.71%、69.15%和56.61%,氨基酸同源性分别为98.10%、83.85%、74.24%、70.26%、62.62%和46.12%,符合物种进化规律。预测的ZP3蛋白二级和三级结构显示它是一个具有22个氨基酸信号肽的亲水性β-桶状跨膜蛋白。牦牛ZP3基因编码区的成功克隆,为进一步研究该基因的结构与功能及其在受精过程中的作用提供了基础。     

天祝白牦牛IGF-2基因的cDNA克隆

旨在克隆天祝白牦牛胰岛素样生长因子2(IGF-2)基因编码区全长cDNA序列,为研究该基因的生理功能奠定基础。运用cDNA末端快速扩增(RACE)技术获得天祝白牦牛IGF-2基因全长cDNA序列。扩增获得天祝白牦牛IGF-2基因全长cDNA序列为1 060 bp(GenBank登录号:KF682139),ORF长540 bp,编码179个氨基酸。其编码的氨基酸与已报道哺乳动物IGF-2氨基酸序列同源性在80%-92%之间。天祝白牦牛IGF-2基因的成功克隆为进一步研究该基因的功能奠定了基础。     

牦牛hnRNP K基因的克隆及序列分析

为研究hnRNP K基因的生物学功能及其在牦牛中的特异性,利用RT-PCR和粘性末端连接法,分两段克隆了牦牛hnRNP K基因cDNA序列。序列分析结果表明,牦牛hnRNP K基因cDNA序列长11706bp,开放阅读框(ORF)长1389bp,编码463个氨基酸。序列比对结果表明,牦牛与黄牛hnRNP K cDNA序列的同源性达99.1%,编码的氨基酸同源性达到97.0%;在牦牛氨基酸序列中有15个突变。通过同源建模的方法成功构建了牦牛hnRNP K蛋白质三级结构,结果表明牦牛hnRNP K属于A型结构,而黄牛hnRNP K蛋白属于B型结构,其差异是由第459-463位氨基酸序列由"ADVEG"突变为"SGKFF"所致。乙酰化分析结果显示,牦牛hnRNP K对基因转录的影响水平跟黄牛是一致,表明不同物种hnRNP K功能的差异可能跟其氨基酸序列的差异有关。成功克隆的牦牛hnRNP K基因的cDNA序列为进一步分析该基因的功能提供参考。     

山羊卵泡刺激素α亚基cDNA的分子克隆与序列分析

从新屠宰的雌山羊脑垂体中提取总RNA ,反转录获得cDNA .以此cDNA为模板用PCR法扩增目的片段 ,获得长为 380bp的山羊卵泡刺激素α亚基cDNA片段 .将它克隆至pMD 18 T Verctor.随机挑选 3个阳性重组子进行测序 ,将测序结果与绵羊、牛、猪等多种哺乳动物该基因的核苷酸序列及相应氨基酸序列进行比较 .结果表明 ,山羊卵泡刺激素α亚基基因氨基酸序列与绵羊、水牛的同源性最高 ,达 96 % ,与牛的同源性达 95 % ,与人的同源性较低 ,为 74 % .山羊卵泡刺激素α亚基基因编码区的核苷酸与绵羊的同源性最高 ,达 95 % ,与水牛、牛的同源性达 94 % ,与马和大鼠的同源性较低 ,为 85 % .总体来看 ,在哺乳类动物中FSHα亚基基因同源性还是很高的 .     

能源植物续随子延伸因子EF1A基因cDNA序列的克隆及分析

利用同源克隆和cDNA末端快速扩增技术(RACE)克隆得到能源植物续随子延伸因子EFIA基因的cDNA序列(命名为ElEF1A,GenBank登录号为KT892703)。序列分析表明,ElEF1A编码序列(CDS)长1344bp,编码447个氨基酸,氨基酸序列具有典型的EF1-alpha、EF1-alpha-Ⅱ和EF1-alpha-Ⅲ结构域。ElEF1A与其他植物EF1A基因的核苷酸序列同源性达到88%以上,推导的氨基酸序列的同源性达95%以上。     

猪CuZnSOD基因的克隆、表达及功能分析

为了进一步了解和认识CuZnSOD基因的结构和功能,揭示CuZnSOD对猪抗氧化机能的影响,寻找与肉质性状相关联的分子标记,文章采用RACE(Rapid amplification of cDNA end)方法,对莱芜猪CuZnSOD基因cDNA进行克隆测序,分析其结构和功能,并用Real-timePCR检测CuZnSOD基因的表达.结果表明,CuZnSOD基因cDNA序列全长658 bp(GenBank登录号:GU944822),包含76 bp的5'UTR和120 bp的3'UTR序列.全部CDS序列462 bp,编码153个氨基酸,分子量为15.9 kDa,等电点为6.03.CuZnSOD基因编码的氨基酸序列中,第3氨基酸残基处存在1个O-糖基化位点,第86氨基酸残基处存在1个N-糖基化位点.二级结构中α螺旋仅占1.31%.在进化过程中高度保守,与人、牛、小鼠和褐鼠的编码区同源性分别为87.74%、87.66%、83.44%和83.23%;氨基酸序列同源性分别为90.26%、94.12%、92.21%和91.50%.CuZnSOD存在典型的金属结合配体结构域(GFHVHQFGDNT).基于蛋白序列所构建的分子进化树表明猪与牛的亲缘关系最近.在mRNA水平上,CuZnSOD是一个广谱表达基因,在大脑、心脏、脾脏、肝脏、肾脏、肺、大肠、小肠、脊髓,肌肉、背膘和胃中都能检测到,其在肾脏,小肠和肺中表达量较高,在心脏和肌肉组织中表达量较低.     

猪POU1F1基因部分序列变异和同源性分析

对长白、杜洛克、约克夏、姜曲海、梅山和香猪等六个猪种的POU1F1基因第四、第五和第六外显子分别进行PCR扩增,并对含有第四、第六外显子的PCR产物和含有第五外显子的克隆产物进行测序。结果表明：六个猪种中,POU1F1基因的第四外显子存在碱基突变,为T→C。对该序列进行Nla Ⅲ 酶消化,产生两种不同的基因型(GG和HH);而第五和第六外显子则高度保守,未发现任何突变。将人POU1F1基因第四外显子、POU同源区核苷酸编码序列和氨基酸序列,分别与猪、小鼠、牛的POU1F1基因相应的核苷酸序列和氨基酸序列进行同源性比较,结果发现：人与猪、小鼠、牛的POU1F1基因第四外显子的核苷酸同源性分别高达93.9%、86.7%、92.1%,而由第四外显子编码的部分POU特异区的氨基酸序列则完全一致;人与猪、小鼠、牛POU同源区的核苷酸同源性分别为91.4%、85.1%、87.9%,氨基酸同源性分别为96.6%、94.8%、90.2%。这说明在哺乳动物中,其POU1F1蛋白的POU同源区和由第四外显子编码的POU特异区部分是高度保守的;猪可作为实验动物,建立人类相关疾病模型,为医学研究提供参考依据。     

梅花鹿卵泡刺激素α-亚基cDNA的分子克隆与序列分析

从新屠宰的母梅花鹿脑垂体中提取总RNA,反转录获得CDNA,以此CDNA为模板用PCR法扩增目的片段,获得长为380bp的梅花鹿卵泡刺激素α-亚基CDNA片段,它将克隆至PMD-18-T-Verctor。随机挑选3个阳性重组子进行测序,并将测序结果与绵羊、牛、猪等多种哺乳动物该基因的核苷酸序列及相应氨基酸序列进行比较。结果表明,梅花鹿卵泡刺激素α-亚基基因编码的氨基酸序列与绵羊、水牛的该基因同源性最高,达97%,只有4个氨基酸不同;与牛的该基因同源性达96%。与人的该基因氨基酸序列同源性较低,为75%。其编码的核苷酸序列与绵羊、水牛、牛的同源性最高,达96%,只有14-16个碱基不同,与人的基因核苷酸同源性最低,为84%,总的来说,哺乳动物的卵泡刺激素α-亚基具有很高的同源性。     

羊草光合作用相关基因的克隆与分析

在构建了羊草叶片cDNA文库的基础上,利用M13载体通用引物筛选其亚文库,挑选阳性克隆进行测序,将测序结果在NCBI基因库中进行比对,得到一个Rubisco大亚基基因全长序列和Rubisco小亚基基因部分序列,并对其核苷酸及其编码的氨基酸序列进行分析。结果显示,Rubisco大亚基基因长度为1 796 bp,与禾本科大麦、小麦、野雀麦、粗山羊草、旱麦草、异形花草、黑麦等的核苷酸序列同源性达98%以上;羊草的Rubisco小亚基基因部分序列含有一个开放阅读框,其长度为186 bp,编码61个氨基酸,与禾本科的小麦、大麦、燕麦、黑麦以及扁穗雀麦Rubisco小亚基基因氨基酸序列的同源性分别为93%、93%、91%、91%、92%。羊草Rubisco基因的克隆与分析有利于进一步研究其光合作用效率。     

Molecular cloning of rabbit gamma heavy chain mRNA.

A cDNA library of rabbit spleen mRNA was screened for immunoglobulin heavy chain sequences. In this paper we report the nucleotide sequence of two cDNA clones containing part of the constant region of the rabbit gamma heavy chain mRNA. The sequence encodes part of the CH2 domain (amino acids 268 to 340), the entire CH3 domain (amino acids 341 to 447) and the 3' untranslated region. This nucleotide sequence has been compared to the corresponding sequences of mouse gamma 1, gamma 2a and gamma 2b genes. The homologies between rabbit gamma chain gene sequence and each of the mouse gamma chain gene sequences are of the same magnitude order. This comparison shows that the CH2 domains are more homologous to each other than CH3 domains or 3' untranslated sequences. The presence of species specific nucleotide positions suggests that mouse gamma chain genes could have evolved from a common ancestor shortly after the mouse-rabbit species separation. Genomic blot analysis of rabbit liver DNA with the rabbit C gamma probes shows a limited number of related sequences, with little restriction site polymorphism between individual rabbits.     

猪口蹄疫病毒受体通用亚基αv的基因克隆及序列分析

病毒受体是病毒宿主范围和组织嗜性的决定因素。研究发现,至少有四种整联蛋白αvβ1、αvβ3、αvβ6、αvβ8是口蹄疫病毒(FMDV)的受体,其中αv是4种受体的通用亚基。首次从口蹄疫病毒实验感染猪的肺组织中克隆到了通用亚基αv基因并对其核苷酸序列和推导的氨基酸序列进行了比较分析。猪αv亚基基因的编码区含有3141个核苷酸,编码1046个氨基酸,其N-端30个氨基酸为信号肽,其后的胞外域、跨膜区、胞浆域分别由955、29、32个氨基酸组成;胞外域含有11个潜在的糖基化位点(NXT/NXS)、2个Ca2 结合位点(DX[D/N]XDGXXD)、18个半胱氨酸残基。猪αv基因与牛、人、猕猴、家鼠、鸡、犬的αv基因的核苷酸序列同源性分别为93.3%、91.5%、91.4%、85.6%、73.2%、89.9%,推导的氨基酸序列同源性分别为96.3%、94.6%、94.1%、90.8%、81.6%、93.8%,猪与牛αv亚基同源性最高,表明受体αv亚基可能与口蹄疫病毒的宿主范围有关。     

The gene encoding hypoxanthine-guanine phosphoribosyltransferase as target for mutational analysis: PCR cloning and sequencing of the cDNA from the rat.

In this paper, the cloning and nucleotide sequence of the cDNA of the rat gene coding for hypoxanthine-guanine phosphoribosyltransferase (hprt) is reported. Knowledge of the cDNA sequence is needed, among other reasons, for the molecular analysis of hprt mutations occurring in rat cells, such as skin fibroblasts isolated according to the granuloma pouch assay. The rat hprt cDNA was synthesized and used as a template for in vitro amplification by PCR. For this purpose, oligonucleotide primers were used, the nucleotide sequences of which were based on mouse and hamster hprt cDNA sequences. Sequence analysis of 1146 bp of the amplified rat hprt cDNA showed a single open reading frame of 654 bp, encoding a protein of 218 amino acids. In the predicted rat hprt amino acid sequence, the proposed functional domains for 5'-phosphoribosyl-1-pyrophosphate (PRPP) and nucleotide binding in phosphoribosylating enzymes as well as a region near the carboxyl terminal part were highly conserved when compared with amino acid sequences of other mammalian hprt proteins. Analysis of hprt amino acid sequences of 727 independent hprt mutants from human, mouse, hamster and rat cells bearing single amino acid substitutions revealed that a large variety of amino acid changes were located in these highly conserved regions, suggesting that all 3 domains are important for proper catalytic activity. The suitability of the hprt gene as target for mutational analysis is demonstrated by the fact that amino acid changes in at least 151 of the 218 amino acid residues of the hprt protein result in a 6-thioguanine-resistant phenotype.     

Molecular cloning of LMO41, a new human LIM domain gene

We have identified a new human LIM domain gene by isolating an autoantigenic cDNA clone from a human breast tumor cDNA library. The predicted amino acid sequence of the cDNA clone's 495 bp open reading frame contains two tandem LIM domain motifs, and within the LIM domain region there is 62% identity with the analogous region of the LIM-only gene LMO1. The homology to LMO1 is restricted to the 360 bp region encoding the tandemly repeated LIM domains, the rest of the open reading frame as well as the extensive, GC-rich 5' untranslated region, and 3' region of the 2 kb cDNA sequence are unrelated to any known genes. This gene has been designated LMO4.     

cDNA cloning of human calpastatin: sequence homology among human, pig, and rabbit calpastatins

cDNA of human calpastatin, an inhibitor protein specific for calpain (EC 3.4.22.17; Ca2(+)-dependent cysteine proteinase) was isolated by screening of a library prepared from human liver mRNA with pig calpastatin cDNA fragment as a probe. The primary structure of human calpastatin was deduced from the nucleotide sequence of the cDNA and compared with that of pig and rabbit calpastatins already reported. Human calpastatin consisted of 673 amino acid residues and had 78% and 77% identity to pig or rabbit calpastatins, respectively. Human calpastatin had a domain structure with four internally repetitive sequences and one N-terminal non-homologous sequence like the other calpastatins. Human calpastatin had two deletions, 22 and 13 residues long in domain L and domain 1, respectively, compared to pig or rabbit calpastatins.     

CAPN11: A calpain with high mRNA levels in testis and located on chromosome 6.

Calpains are a superfamily of related proteins, some of which have been shown to function as calcium-dependent cysteine proteases. In mammals, eight different calpains have been identified. We report the identification of a new mammalian calpain gene, CAPN11. The predicted protein possesses the features typical of calpains including potential protease and calcium-binding domains. The CAPN11 mRNA exhibits a highly restricted tissue distribution with highest levels present in testis. Radiation hybrid mapping localized the gene to human chromosome 6, within a region mapped to p12. Phylogenetic analysis suggests that, in mammals, the predicted CAPN11 protein is most closely related to CAPN1 and CAPN2. However, of the calpain sequences available, the predicted CAPN11 sequence exhibits greatest homology to the chicken micro/m calpain. Thus CAPN11 may be the human orthologue of micro/m calpain. The discovery of this new calpain emphasizes the complexity of the calpain family, with members being distinguished on the basis of protease activity, calcium dependence, and tissue expression.