黄鳝基因组中存在酪氨酸蛋白激酶受体基因同源序列

近年的研究表明,酪氨酸蛋白激酶受体通过其细胞膜外部的结构域与细胞外的信号分子配体结合后,激活本身位于细胞质内的激酶结构域,磷酸化的酪酸进而激活下游一系列信号分子。这些分子的激活引起细胞内基因表达的改变,最终导致细胞本身表型状态的变化。本文发现并研究了存在于鱼类中的酪氨酸蛋白激酶受体基因的同源序列matk。实验用黄鳝和胡子鲇为集市采购。PCR扩增采用人SRY基因编码区的一对引物,分别为：5′CCCGAATTCGACAATGCAATCATATGCTTCTGC3′和5′CTGTAGCGGTCCCGTTGCTGCGGTG3′。分别制备雌雄性黄鳝基因组DNA,进行PCR扩增。2％琼脂糖凝胶电泳分析表明,雌雄性样品中均可见到约250bp的扩增带。将雄性的扩增产物matk重组pUC13载体上。对其进行测序,结果表明：matk与人SRY和SRY盒基因序列无同源性,而与最近才报道的大鼠酪氨酸蛋白受体基因ptk3cDNA5′端序列具有56％的序列一致性（图1）。有报导,人与鼠的酪氨酸蛋白激酶受体基因DDR和ptk3存在96％的同源性。表明这种酪氨酸蛋白受体基因具有很强的保守性。以matk为探针,对经过EcoRI酶切过的雌雄黄鳝的胡子鲇（为对照）的基因组DNA进行Southern印迹分析。杂交结果（图2）显示：实验组的雌雄性黄鳝中,在3．3Kb和2．2Kb处均有两条一致的杂交带;而对照组中没有杂交带。说明黄鳝中存在酪氨酸蛋白激酶受体同源序列,有两个抟。类似地：果蝇和线虫的胰岛素受体基因scvenless和EGF／TGF－α等在哺乳动物中均有各自的同源基因－rasl和lin－3等。本研究结果有助于了解信号传导机制及其在水生动物到陆生动物中的进化模式。     

ZFX基因同源序列在黄鳝基因组中的检出及其染色体定位

以大熊猫锌指蛋白基因Zfx为探针 ,在黄鳝基因组DNA中检测到一条长约 9 5kb的杂交带。依据哺乳类和爬行类动物锌指蛋白基因 (ZFX/Zfc)编码第 7～ 13个锌指结构的DNA序列保守性设计引物 ,在黄鳝基因组DNA中仅扩增到一条 5 12bp的DNA片段。将此片段克隆至载体 pBS中 ,从雌性、雄性个体中分别挑选 4个含有插入片段的白色克隆进行测序。测序结果表明 ,这些克隆中插入片段的核苷酸序列一致。该DNA片段在核苷酸水平上与人类ZFX和ZFY分别具有 88%和 87%同源性 ,但其与美洲鳄鱼Zfc的同源性可达 90 % ,而在氨基酸水平上则分别存在 95 9%、95 9%和 93 5 %的同源性 (170个氨基酸 )。该基因命名为黄鳝锌指蛋白基因Zfa ,并运用FISH将其定位于黄鳝 1号染色体 ,距离着丝粒的相对位置为 6 0 1± 0 38。通过进一步研究证明 ,黄鳝 1号染色体上存在有真兽类哺乳动物X染色质同源的保守片段 ,该保守片段有可能就是哺乳动物X染色体起源和进化的原始物质基础之一。应用哺乳动物X染色体连锁的其他基因在鱼类开展染色体比较定位研究 ,将有望促进脊椎动物性染色体进化的深入研究     

水稻全基因组编码抗病基因同源序列分析

利用模糊搜索的方法,在TIGR水稻日本晴基因组数据库(TIGR Rice Genome Annotation-Release5)中识别出565个编码抗病蛋白质的同源序列;利用识别出565个编码抗病蛋白质序列分别与籼稻基因组数据库进行BLASTP联配,共确定320个对应的等位基因。通过在线生物信息学软件,识别了这565个抗病基因的保守结构域、保守模体和DNA序列内转座子元件,其中有14个抗病基因同源序列注释错误。同时绘出了这些基因的基因组分布,并基于这些基因的同源树分析和基因组物理分布,认为基因的原位和远程复制事件产生了抗病基因的现存分布和多样性,其中转座子在复制过程中扮演了重要角色。这些对抗病机制研究和抗病基因进化研究以及抗病基因的转育具有重要意义。     

基因组序列的大尺度同源分析

本文报道了一种大尺度基因组现源分析方法,利用散列检索技术和稀疏动态规划算法实现快速的序列比较。经植物叶绿体基因组,哺乳类Ｔ细胞受体基因哺乳类眼γ－晶状体基因簇等实例应用,证明了此方法可以十分快捷地提供足够精确的联配结果,可实际应用基因组序列分析。     

头颈部肿瘤基因组中HPV16DNA的同源序列

利用头颈部肿癌临床活检新鲜组织和石蜡包埋组织的两种处理标本,分别采用核酸分子杂交和聚合酶链反应(PCR)两种技术,分析了头颈部肿瘤组织基因组中人乳头瘤病毒16型的同源序列,并研究HPV16的感染同头颈部肿瘤发生发展的关系。结果表明:1.喉鳞状细胞癌DNA中有HPV16 DNA同源序列,检测频率在20.0％以上。2.PCR扩增石蜡包埋肿瘤组织DNA中HPV16的URR(病毒基因上游调控区)中的序列,电泳分析扩增产物在喉乳头状瘤、喉癌、鼻腔内翻性乳头瘤和口腔癌中检测率分别是11.1％、20.0％、42.9％和27.3％。3.研究表明HPV16 DNA阳性率与喉癌原发部位,分化程度和临床分期之间可能有一定的相关性。人乳头瘤病毒可能是头颈部肿瘤的病毒病因之     

酪氨酸蛋白激酶型受体亚族的研究概况

已知许多生长因子的效应通过高亲和性受体酪氨酸激酶(Receptor Tyrosine Kinase,RTK)所介导。RTK信号通路,与已确认的第二信使系统即cAMP系统、Ca~(2 )系统和肌醇磷脂信号系统相互作用,相互协调以进行生物体正常生理活动。10年来,先后证实有9类RTK亚族(图1),各亚族成员以其独特的结构特点区别于其他亚族。 尽管RTK亚族间存在差异,但就信号发放途径而言,在很大程度上表现出共同性。配体结合胞外区城后,激活胞浆的酪氨酸激酶,导致下游大量共同发信号分子活化。经常受到激活的这类蛋白质有:磷脂酶C-γ(PLC-γ)、     

水稻NBS-LRR类R基因同源序列

根据多数抗病基因(R)编码蛋白质的核苷酸结合区(nucleotide binding site, NBS)和富含亮氨酸重复(leucine-rich repeat,LRR)保守区域特点,设计PCR特异扩增引物,从水稻中克隆了大小约为520 bpDNA片段23个.通过序列同源比较分析发现, 它们编码的蛋白质氨基酸序列包括有NBS-LRR类基因所具有的kinase-1a,kinase-2a, kinase-3a和保守的domain 2区域,它们属于R基因同源序列(R gene homologous sequence, 简称RS).聚类结果发现它们分为4类.遗传定位结果表明它们分布在1,3,4,7~11染色体上,其中10个RS位于已知R基因所在的染色体区间.用水稻抗白叶枯病基因Xa4的近等基因系和基因累加系对克隆的NBS-LRR同源序列进行RFLP分析,发现序列RS13可能来自Xa4基因家族.     

植物体中类受体蛋白激酶

植物体中类受体蛋白激酶是蛋白激酶家族中重要的一类。它们的基因结构及其产物（蛋白）结构特征和主要生理功能文中作了简要介绍。     

Melatonin is Involved in Sex Change of the Ricefield Eel, Monopterus albus Zuiew

The ricefield eel (Monopterus albus Zuiew), a burrowing eel-like synbranchoid teleost, undergoes a natural sex change from female to male during its life history. Since the teleost pineal gland and its melatoninergic output have been suggested as regulators in seasonal reproduction and sexual maturation in many fish species, it is reasonable to postulate that melatonin may play important roles in the ricefield eel’s sex-change process. This hypothesis was tested by examining secretional characteristics and reproductive effects of melatonin in the ricefield eel. Results indicate that serum melatonin (mainly secreted from the pineal complex, retinae and gastrointestinal tract) is involved in sex change of this species. It seems that, within a reproductive cycle, relatively lower mid-night serum melatonin (MNSM) levels are necessary for natural spawning, but relatively higher MNSM levels after spawning permit initiation of the sex-change process. A putative model is presented to clarify the involvement of melatonin in natural sex change of the ricefield eel, although the precise mechanisms are still under further investigation.     

PI3-Kinase Is Involved in Mitogenic Signaling by the Oncogenic Receptor Tyrosine Kinase Xiphophorus Melanoma Receptor Kinase in Fish Melanoma

Overexpression of the mutationally activated receptor tyrosine kinase Xiphophorus melanoma receptor kinase (Xmrk) initiates formation of hereditary malignant melanoma in the fish Xiphophorus. In melanoma as well as in a melanoma-derived cell line (PSM) this receptor is highly activated resulting in constitutive Xmrk-mediated mitogenic signaling. In order to analyze mitogenic signaling triggered by Xmrk a possible involvement of phosphatidylinositol 3 (PI3)-kinase in Xmrk signal transduction was examined. Constitutive binding of the p85 adapter subunit of PI3-kinase to the Xmrk receptor was detected in PSM melanoma cells. Further analyses in BHK cells expressing a Xmrk chimera (HER-mrk) showed that p85 association with the intracellular part of Xmrk was dependent on autophosphorylation of the receptor. In vitro binding studies revealed that the interaction is mediated mainly through the N-terminal SH2 domain of p85 which directly binds to a sequence motif around phosphorylated Tyr-983 in the Xmrk carboxy-terminus. In accordance with recruitment of p85 by Xmrk in PSM cells, the PI3-kinase downstream target Akt was found to be highly phosphorylated on Ser-473, indicating efficient PI3-kinase signaling in melanoma cells. PI3-kinase activation was also detected in Xiphophorus melanoma. Moreover, malignant melanomas exhibited an increased level of PI3-kinase activity which was about three times higher than that in benign pigmented lesions. Inhibition of PI3-kinase activity in PSM melanoma cells by both Wortmannin and LY294002 blocked entry into S-phase. Together these data demonstrate that PI3-kinase is a substrate of the oncogenic Xmrk receptor and plays a significant role in mitogenic signaling of melanoma cells and the formation of malignant melanoma in Xiphophorus.     

Integrin Signaling: Cytoskeletal Complexes,MAP Kinase Activation,and Regulation of Gene Expression

Members of the integrin family of adhesion receptors mediate interactions of cells with the extracellular matrix. Besides their role in tissue morphogenesis by anchorage of cells to basement membranes and migration along extracellular matrix proteins, integrins are thought to play a key role in mediating the control of gene expression by the extracellular matrix. Studies over the past 10 years have shown that integrin-mediated cell adhesion can trigger signal transduction cascades involving translocation of proteins and protein tyrosine phosphorylation events. In this review, we discuss approaches used in our lab to study early events in integrin signalling as well as further downstream changes.     

SNFL3: A Protein Kinase Homologue of Sorghum bicolor with a High Similarity to the Yeast SNF1 Protein Kinase

We have identified several protein kinases that are differentially expressed in mesophyll and bundle sheath cells of the C4 plant Sorghum bicolor. Here we describe the characterization of a protein kinase homologue that shows a high amino acid sequence similarity to the SNF1/AMPK family of protein serine/threonine kinases. The mRNA of this gene accumulates to much higher levels in mesophyll cells than in the bundle sheath and can also be detected in root tissue.     

玉米类受体蛋白激酶基因ZmLRRPK1的cDNA克隆与表达分析

富亮氨酸重复区的类受体蛋白激酶(LRR-RLKs)在植物对多种信号的响应中发挥作用。应用电子克隆的方法在玉米中克隆了一个LRR-RLKs类基因的全长cDNA,命名为ZmLRRPK1（GenBank接受号为EU873320）。推断的ZmLRRPK1蛋白含有594个氨基酸,分子量为66kDa,等电点pI为5.42,具有典型的LRR-RLKs结构域。半定量RT-PCR结果表明,在ABA、甘露醇和氯化钠的诱导下,ZmLRRPK1在玉米胚芽鞘中表达并在24 h内保持较高的转录水平。     

Larval Gnathostoma spinigerum Detected in Asian Swamp Eels,Monopterus albus,Purchased from a Local Market in Yangon,Myanmar

The present study was performed to determine the infection status of swamp eels with Gnathostoma sp. larvae in Myanmar. We purchased total 37 Asian swamp eels, Monopterus albus, from a local market in Yangon in June and December 2013 and 2014. All collected eels were transferred with ice to our laboratory and each of them was examined by the artificial digestion technique. A total of 401 larval gnathostomes (1-96 larvae/eel) were detected in 33 (89.2%) swamp eels. Most of the larvae (n=383; 95.5%) were found in the muscle. The remaining 18 larvae were detected in the viscera. The advanced third-stage larvae (AdL₃) were 2.3-4.4 mm long and 0.25-0.425 mm wide. The characteristic head bulb (0.093 × 0.221 mm in average size) with 4 rows of hooklets, muscular long esophagus (1.025 mm), and 2 pairs of cervical sacs (0.574 mm) were observed by light microscopy. The average number of hooklets in the 1st, 2nd, 3rd, and 4th rows was 41, 45, 48, and 51, respectively. As scanning electron microscopic findings, the characteristic 4-5 rows of hooklets on the head bulb, a cervical papilla, tegumental spines regularly arranged in the transverse striations, and an anus were well observed. Based on these morphological characters, they were identified as the AdL₃ of Gnathostoma spinigerum. By the present study, it has been confirmed for the first time that Asian swamp eels, M. albus, from Yangon, Myanmar are heavily infected with G. spinigerum larvae.     

Nucleotide Sequence of a Putative Sensory Kinase Gene from the Cyanobacterium, Anacystis nidulans 6301

The nucleotide sequence of a 2,146 bp portion of the Anacystisnidulans (Synechococcus PCC6301) genome has been determined.This region contains an open reading frame (ORF) of 392 codons,whose predicted protein sequence shows partial homology to thoseof E. coli phoM and envZ. Hence ORF392 is suggested to be asensory kinase gene in cyanobacteria.