威宁绵羊和贵州半细毛羊STAT5b基因部分外显子SNP研究

为给贵州本地绵羊选种选育提供更好的科学依据,本试验利用威宁绵羊和贵州半细毛羊构建DNA池,设计4对引物扩增其STAT5b基因部分外显子及内含子序列。PCR产物经纯化后进行双向测序。利用DNAStar和BLAST分析确定多态性位点。利用生物信息学软件分析SNPs位点对STAT5b基因RNA二级结构、STAT5b蛋白二级及三级结构的影响。结果表明,在扩增的STAT5b基因中筛选到6个SNPs:exon5-G12A、exon8-G56A、exon8-C104T、intron2-A3164C、intron4-C1026T和intron5-T3323C,其中exon8-G56A为错义突变,导致编码的谷氨酸(Glu)变为赖氨酸(Lys);exon5-G12A和exon8-C104T多态位点均未改变氨基酸的编码,为同义突变;intron2-A3164C、intron4-C1026T和intron5-T3323C均在内含子区,不参与氨基酸编码。     

家兔UCP2基因多态性的筛选和生物信息学研究

本文研究兔的UCP2基因的多态性,为地方兔种的选种和选育提供一定的依据。分别以比利时兔、加利福尼亚兔和新西兰兔构建其DNA池,设计6对引物扩增3个兔种UCP2基因的外显子序列和部分内含子序列,用PCR产物直接进行双向测序快速的筛选出兔的UCP2的多态位点。结果表明:在兔UCP2基因中筛选到8个多态性位点:intron2-G2217T、exon3-A63C、exon3-G169A、intron5-C61A、exon6-C11G、intron6-C7T、intron6-C46T、intron6-C73A,其中exon3-A63C和exon3-G169A位于第3外显子上,且exon3-A63C为错义突变,导致编码的酪氨酸(Tyr)变为丝氨酸(Ser)。exon6-C11G在第6外显子上,其余的多态位点都在内含子中,除了intron6-C7T外,其余的多态位点在三种兔种中都有。结论:通过生物信息学对兔UCP2基因的分析发现m RNA二级结构、二级结构和蛋白质的三级结构在突变前后都发生变化。     

中国汉族女性TLR7基因主要编码区的全长扩增及多态性分析

目的:扩增TLR7主要编码区外显子3(exon 3)的全长基因片段并进行基因多态性分析,筛选健康人群中TLR7基因的主要SNP位点.方法:采用酚-氯仿抽提方法从28例健康女性血样中提取基因组DNA,采用长片段扩增方法分别扩增TLR7 exon 3区的3个片段,测序、拼接后进行多态性分析.结果:采用LA-Taq酶体系成功扩增TLR7 exon 3区基因片段;经与Genbank数据库中TLR7参考序列比较,我国女性TLR7基因序列高度保守,仅出现了4个点突变,并发现1个SNP位点RS3853839,表现为GG、CG和CC三种基因型.结论:建立了TLR7编码区基因扩增方法,筛选到1个TLR7SNP位点RS3853839,可为分析TLR7多态性与多种病毒感染性疾病的关系提供参考.     

苏太猪ELOVL7基因的生物信息学分析

不同于人、鼠等物种ELOVL7基因的高相似度,不同品种的猪ELOVL7基因相似度较低。为了探究该基因的特性,本研究运用生物信息学的方法对苏太猪ELOVL7基因及其氨基酸序列的同源性、理化性质、保守结构域、亚细胞定位、信号肽、跨膜结构域、亲水性/疏水性、二级结构、功能预测以及磷酸化位点等进行预测分析。结果表明：在苏太猪中,ELOVL7全长2 324 bp,编码区为846 bp,共编码281个氨基酸。其结构稳定,分子量为33 387.4 Da,带正电荷,偏碱性。该基因所编码的蛋白质最可能位于细胞膜上,主要的功能是运输和结合,为跨膜、非分泌型疏水蛋白质,含有1个GNS1/SUR4家族的保守结构域,并有15个丝氨酸激酶、15个苏氨酸激酶和20个酪氨酸激酶潜在磷酸化位点。α螺旋是ELOVL7二级结构和三级结构中最主要的结构元件。另外ELOVL7与大部分物种的氨基酸序列相似性达90%以上,且亲缘关系较近。分析ELOVL7基因及其氨基酸序列的特征,能够为进一步挖掘该基因内的突变对长链脂肪酸表型的影响以及合成、代谢机理提供分子依据。     

男性性腺功能减退症的致病基因分析

[目的]通过全外显子组测序(WES)技术筛选男性性腺功能减退症的致病基因,并对基因突变位点进行生物信息学分析。[方法]收集5例男性性腺功能减退症患者临床及遗传学检测资料。采用WES技术筛选相关致病基因,并通过PCR扩增、Sanger测序以及生物信息学分析等验证突变位点。[结果]先证者1为PROKR2基因c.533G>C(p.W178S)纯合突变,家系验证结果发现其父母均为PROKR2基因c.533G>C(p.W178S)杂合突变携带者,符合常染色体隐性遗传。先证者2为ZFPM2基因c.1498C>G(p.Q500E)杂合突变,生物信息学分析发现,该突变位点编码的氨基酸在不同物种中高度保守,并在人类外显子数据库、参考人群千人基因组1000G、SNP数据库及人群基因组突变频率数据库中未发现该突变位点,该突变经SIFT、Polyphen2和Mutation Taster软件预测结果均为有害。[结论]PROKR2基因c.533G>C(p.W178S)和ZFPM2基因c.1498C>G(p.Q500E)突变可能是男性性腺功能减退症的致病原因。     

林麝MHC-DRA基因分析及与反刍亚目DRA基因比较

MHC-DRA基因仅在少部分物种如马、斑马、驴等具有多态性,DRA基因在其他哺乳动物中多为低多态性。由于MHC-DRA的低多态性,较少受到研究者重视,我们选取近缘物种牛的DRA基因引物,对四川养麝研究所的217只林麝进行DRA基因exon 2的序列扩增,得到2个林麝DRA基因,片段长度为260 bp,这2个基因仅有一个核苷酸同义突变,没有氨基酸突变。我们将所获得的林麝DRA基因与反刍亚目其他物种DRA基因进行氨基酸比对发现,我们扩增的序列为林麝DRA基因exon 2,编码MHCⅡ类分子的α1区域,而这段区域主要参与形成MHCⅡ类分子的多肽结合槽,根据Brown确定人类的抗原肽结合区位点,在参与比对的反刍亚目物种DRA基因中,抗原位点11、22、72、76存在氨基酸变异,而在这些位点上林麝的DRA基因没有变异,和大部分反刍亚目相同。同时我们发现大部分反刍亚目物种之间氨基酸突变的位点大都在非抗原结合位点。     

中国荷斯坦牛ABCG2基因编码区多态性检测及生物信息学分析

目的：研究中国荷斯坦牛ABCG2基因编码区（CDS）多态性,并进行生物信息学分析。方法：以中国荷斯坦牛为材料,利用PCR-SSCP技术对ABCG2基因CDS多态性进行检测,然后预测蛋白质序列的改变,并用生物信息学软件对蛋白质序列突变前后的结构及性质进行分析。结果：在外显子9中存在一个A→G碱基突变,导致氨基酸由酪氨酸突变为半胱氨酸,将此突变命名为Y367C;在外显子14中存在一个G→A突变,导致氨基酸由精氨酸突变为谷氨酰胺,将此突变命名为R578Q。2个突变一个位于功能区与跨膜区之间,一个位于跨膜区。生物信息学分析发现,蛋白质二级结构增加了1个卷曲（C）和2个转角（T）,同时减少了3个β折叠（E）,且ABCG2蛋白的组成和一些性质也发生了改变。结论：检测到的2个单核苷酸多态性引起了ABCG2蛋白性质和二级结构的改变;为进一步研究ABCG2蛋白对产乳性状的影响奠定了基础。     

贵州地方山羊CAST基因外显子6、7和8的多态性分析

为分析山羊CAST基因的多态性,筛选出对山羊肉质性状有显著影响的SNPs位点,本研究以黔北麻羊和贵州黑山羊为试验对象,构建DNA池,采用PCR产物直接测序法对2个品种山羊该基因的外显子6、7和8进行单核苷酸多态性检测,估算各SNPs等位基因频率,并利用在线软件预测突变前后的m RNA二级结构及理化特性。结果显示,所设计引物的扩增片段发现1个同义突变,位于外显子8中的T81C。利用生物信息学软件对外显子8中的T81C位点进行分析,结果表明这个SNPs位点导致编码的m RNA二级结构以及理化特性的改变。     

威宁绵羊GHR基因多态性分析

为了更好地保护和开发利用威宁绵羊这一优良地方品种,本试验利用威宁绵羊构建DNA池,设计8对引物扩增威宁绵羊GHR基因外显子及部分内含子序列。将PCR产物纯化并进行双向测序,通过DNAStar和BLAST等生物软件分析确定SNP位点。利用生物信息学软件分析SNPs对GHR基因的m RNA二级结构的影响、生长激素受体二级和三级结构的改变。结果表明,在扩增的GHR基因中筛选到4个SNPs:Exon1-C~(112)T、Exon4-C~7T、Exon8-A~(27)T、Intron4-C~(27)T,其中Exon8-A~(27)T为错义突变,导致编码的异亮氨酸(Ile)变为苯丙氨酸(Phe);Exon1-C~(112)T和Exon4-C~7T位点对其编码的氨基酸没有影响,是同义突变;Intron4-C~(27)T在内含子区,不参与氨基酸编码。本研究将为更好地保护和开发利用威宁绵羊提供一些参考。     

牛卵巢PRSS35基因CDS序列分析

为测定牛卵巢丝氨酸蛋白酶35 (PRSS35)的CDS序列并进行生物信息学分析。试验根据NCBI上已公布牛PRSS35基因的mRNA序列设计特异性引物,使用RT-PCR技术扩增牛卵泡中PRSS35的CDS序列。结果显示,牛PRSS35基因CDS区序列全长为1 239 bp,共编码412个氨基酸,PRSS35与其他10个物种的同源序列相似性较高,且该蛋白具有一个长度为20个氨基酸的信号肽,具有11个O-糖基化位点和2个N-糖基化位点,以及3个磷酸化位点,并发现有一个典型的Tryp_Spc结构域,即胰蛋白酶样丝氨酸蛋白酶结构域。为进一步研究该基因及其编码蛋白在卵泡发育过程中所起的作用提供了一定的理论依据。     

FHF-2 in the turkey (Meleagris gallopavo)

A cDNA clone homologous to the fibroblast growth factor homologous factor (FHF-2) was isolated and sequenced from the turkey (Meleagris gallopavo). The DNA sequence of the turkey was almost identical to that of the chicken (99% similarity) differing at only 8 of 770 nucleotides in the coding region resulting in a single amino acid difference between these poultry species. The 3'UTR of the turkey FHF-2 gene was 445 nucleotides in length and included an imperfect CT microsatellite (ms) repeat. The sequence of the 3'UTR was amplified from genomic DNA of the chicken and found to be highly conserved differing at only three nucleotides when compared to the turkey. Length of the CT repeat was indifferent in a sample of 52 turkeys (monomorphic) however, the number of CT repeats was greater in the turkey than in the chicken. No inter-individual polymorphism was detected in multiple sequences of the 3'UTR of the FHF-2 gene in the turkey. Based on comparison of the turkey and chicken sequences, the mutation rate for coding and associated non-coding (3'UTR) regions of FHF-2 are approximately equal.     

五个鸡群中催乳素基因密码子使用频率与产蛋量的关系分析

通过鸡催乳素基因编码区基因扫描,发现3个SNP位点,分别是外显子2的C1607T、外显子5的C5749T和T5821C,3个SNP均没有改变氨基酸的编码.同时发现不同的单倍型间存在不同的密码子使用频率.对5个鸡群共370只鸡进行SSCP的基因型检测,共发现7种单倍型,结合44周龄产蛋量分析,发现不同单倍型的平均产蛋量存在显著性差异.结合密码子使用频率分析,发现使用高频密码子的单倍型个体产蛋量相对高.通过酶联免疫方法检测催乳素表达量,结果显示,使用高频密码子的个体,激素水平较高,其中使用2个高频密码子的单倍型个体和使用1.5个密码子的单倍型个体之间存在极显著差异.研究结果表明,密码子使用频率与产蛋量在一定的范围内呈现正相关趋势.     

Atrophic macular degeneration mutations in ELOVL4 result in the intracellular misrouting of the protein

Elongation of very long chain fatty acids 4 (ELOVL4) is a novel member of the ELO family of genes that are involved in fatty acid metabolism. ELOVL4 encodes a putative transmembrane protein of 314 amino acids that carries a possible endoplasmic reticulum (ER) retention/retrieval signal (KXKXX) at the C-terminus. Two distinct mutations, a 5-bp deletion and a complex mutation from the same region in exon 6 of this gene, have been reported so far and are associated with autosomal dominant atrophic macular degeneration (adMD/STGD3). Both of these deletions could result in C-terminal truncation and loss of the ER retention signal in the mutant protein. We expressed the wild-type and mutant proteins in COS-7 and CHO cells to study the intracellular distribution of ELOVL4 and to identify possible implications of the above mutations in its localization. Immunofluorescence analysis of these proteins along with organelle marker antibodies revealed predominant ER localization for wild-type ELOVL4. Targeted deletion of the dilysine motif at the C-terminus of the protein resulted in the loss of ER localization. Immunoelectron microscopy and immunofluorescence analysis revealed a similar ER localization pattern for the protein in human photoreceptors. These data indicate that ELOVL4 is an ER-resident protein, which supports its suggested function in fatty acid elongation. We also demonstrate that the localization of both mutant proteins was dramatically changed from an ER to a Golgi distribution. Our observations suggest that the consequences of defective protein trafficking could underlie the molecular mechanism associated with degeneration of the macula in the patients with adMD/STGD3.     

Molecular and genetic analysis of a compound heterozygote for dysprothrombinemia of prothrombin Tokushima and hypoprothrombinemia.

The molecular and genetic basis of a compound heterozygote for dys- and hypoprothrombinemia was analyzed. Abnormal nucleotide sequences of the human prothrombin gene were screened by PCR-single-strand conformation polymorphism (PCR-SSCP) with endonuclease digestion and mutated primer-mediated PCR-RFLP. A single nucleotide substitution responsible for dysprothrombinemia of prothrombin Tokushima was detected, as were three polymorphisms. The mutation for hypoprothrombinemia was detected by PCR-single-strand conformation polymorphism (PCR-SSCP) with endonuclease digestion in exon 6, near MboII-RFLP and NcoI-RFLP. Sequencing of PCR-amplified genomic DNA revealed a single base insertion of thymine (T) at position 4177. The resulting frameshift mutation caused both an altered amino acid sequence from codon 114 and a premature termination codon (i.e., TGA) at codon 174 in exon 7. Because exon 7 encodes the kringle 2 domain preceding the thrombin sequence, this frameshift leads to the null prothrombin phenotype. The inheritance of the hypoprothrombinemia gene from the father to the proband was proved by PCR-SSCP with endonuclease digestion and mutated primer-mediated PCR-RFLP.     

鸡补体分子C3d的基因克隆及结构分析

目的:克隆鸡补体分子C3d基因并解析其结构特点。方法:将已发表的人、小鼠、地鼠、奶牛、野兔、猪、猩猩、绵羊的C3d基因同鸡的C3α链进行序列比较分析,发现在鸡的C3α链上有一段约897bp的序列同上述动物有较高的同源性,在上下端保守区域设计一对引物788bp,应用RT-PCR扩增鸡C3d部分基因,并克隆到pMD18-T载体中,测序正确后再在上下端分别设计一对引物,理论长度分别为378和336bp,最后用3种PCR产物延伸扩出C3d全长序列。结果:获得了鸡C3d基因重组质粒pMD18-C3d,序列分析表明所获的鸡C3dcDNA全长为993bp,编码331个氨基酸残基。鸡与上述人或动物C3d核苷酸的同源性分别为66.6%、66.2%、67.7%、66.2%、67.1%、67.0%、59.6%、67.1%,与其编码的氨基酸的同源性分别为61.5%、61.9%、61.2%、61.9%、56.5%、61.9%、54.5%、61.5%;而哺乳动物间C3d的核苷酸和氨基酸的同源性则分别为74.2%～100%和72.2%～100%。进化树反映出C3d基因具有种的多样性,亲缘关系越近,进化关系也越近。结论:鸡C3d与其他动物的C3d在抗原结合位点上没有氨基酸的变化,而与CR2结合的28肽区氨基酸差异明显,说明鸡C3d结合抗原没有专一性,而结合免疫细胞则有种的特异性,由此可以推测鸡C3d只能增强鸡的特异性免疫反应。     

Polymorphisms in chicken extracellular fatty acid binding protein gene

In this study, we report the investigation of extracellular fatty acid binding protein gene (Ex-FABP) genetic polymorphism in a sample of 360 chicken individuals. The screening of the coding regions with their intron–exon boundaries and the proximal flanking regions was performed through a PCR-SSCP strategy. Following sequence analysis revealed 35 novel single nucleotide polymorphisms (SNPs) of chicken Ex-FABP gene. Among the 35 SNPs, twenty-five were found in the introns. And the remaining seven and three SNPs were in the coding region and the 5′UTR, respectively. Two SNPs in the coding region caused two missense mutants and the other five did not result in any amino acid changes. The nature and the distribution of Ex-FABP mutations in three chicken breeds were analyzed. Variations detected here might have an impact on Ex-FABP activity and function and underpin the development of gene markers for chicken fatty deposition and metabolism. The polymorphism, generated by C4715T mutation in exon5, was significantly associated with thickness of subcutaneous fat plus skin in cocks. Subcutaneous fat plus skin of cocks was more thick in TT genotype than in CC genotype (P < 0.05). The Ex-FABP gene could be a candidate locus or linked to a QTL that significantly affects fatty deposition and metabolism in chicken.     

MHC-DRB exon 2 allele polymorphism in Indian river buffalo (Bubalus bubalis)

The polymorphism of the major histocompatibility complex (MHC) class II DRB gene of riverine buffalo (Bubalus bubalis) was studied. Second exon sequences from the buffalo DRB locus, homologous to the cattle DRB3 gene, were amplified and characterized. A combination of single strand conformation polymorphism (SSCP) and heteroduplex analysis (HA) in a non-denaturing gel was used to identify new DRB second exon sequences. SSCP, HA and finally sequencing allowed the identification of 22 MHC-DRB exon 2 alleles from 25 unrelated Indian river buffalo. These are the first river buffalo DRB second exon sequences reported. A high degree of polymorphism in the sequences encoding the peptide binding regions was observed and some amino acid substitutions were found unique to the river buffalo.