ADAMs与哺乳动物受精

ADAMs是近几年发现的一类具有多个结构区和广泛生物学功能的糖蛋白,它们在哺乳动物受精中的作用日益得到实验结果的支持,本文简要总结了近几年ADAMs在哺乳动物受精中作用的研究进展。     

哺乳动物的受精

受精是单倍体配子（精子和卵子）融合产生新生命的过程,是有性生殖个体发育的起点。根据动物种类的不同,受精可以发生在体内,也可以发生在体外。它一方面恢复了染色体双倍体数目,保证了双亲的遗传作用;另一方面,受精可以把生殖细胞通过减数分裂同源重组获得遗传物质变化和个体发生过程中产生的变异遗传下去,保证了物种的遗传多样性,在生物进化上具有重要意义。     

哺乳动物受精的生物学

哺乳动物的受精(Mammalian Fertilization)是两性配子(精子和卵子)相结合而形成合子的过程,它标志着胚胎发育的开始,也即是一个新生命的起点。受精是生物学家饶有兴味的课题。因为它不仅涉及到一个理论问题,更重要的是当今节育和不育的世界性问题尚未解决,因此,受精的重要性是不言而喻的。当然,受精是一个极其复杂的生命现象,涉及到两性配子的发育和成熟、精子获能、顶体反应、精卵激活、精子     

受精环境对哺乳动物性别形成的影响

性别控制是人类很早就关心的研究领域, 许多重要的经济性状与性别有直接的关系。控制受精环境即可控制性别, 这种方法不需昂贵的仪器设备或者药品, 易实践, 可普遍应用, 其经济效益和社会效益难以估量。文章综述了受精环境对哺乳动物性别形成影响的研究进展。这些环境因素包括母体生殖道中精氨酸含量、胚胎发育过程中子宫内葡萄糖浓度、输精时卵母细胞成熟程度以及哺乳动物受孕时生殖激素的水平等方面, 为进一步开展性别控制研究积累一定的资料。     

哺乳动物精卵融合机制

最近基因打靶研究揭示出了参与精卵结合和融合的各种分子。精子中ADAMs因子（是含有裂解蛋白和金属蛋白酶结构域蛋白质家族）,包括繁殖因子α、繁殖因子β以及cyritestin,经过研究已经发现它们对精卵结合有重要作用,而对精卵的融合不重要。通过研究推测出其受体为卵母细胞整合蛋白,其对精卵交互作用是必需的。最近,一些研究表明CD9和卵母细胞上GPI锚定蛋白（glycosyl phosphatidyl inositol糖基磷脂酰肌醇）,以及精子上的附睾蛋白DE均是精卵融合过程中的侯选因子,如果缺乏这些蛋白质分子或其作用受到干扰将导致精卵融合机制紊乱。综述重点讨论了参与精卵交互作用的相关分子的最新研究进展。     

ADAMs参与哺乳动物精-卵结合与融合

ADAMs家族是含多结构域的跨膜蛋白。睾丸特异的ADAMs,在精子发生与附睾精子转运过程中,经过蛋白水解成为成熟精子的分子形式,与精．卵质膜结合和融合有关。对于精-卵质膜相互作用,ADAMs去整合素域具有关键氨基酸残基和特殊模体。模拟ADAM2和ADAM3去整合素域的短肽能用于鉴别特异性卵子识别蛋白。精子ADAMs去整合素域与卵子膜蛋白整合素β1、α4／α9、α6和CD9相互作用,介导了精卵质膜的结合与融合。     

ADAMs与生长发育

ADAMs是近几年发现和鉴定的一类具有多个结构域和广泛生物学功能的细胞表面糖蛋白,由信号肽区、前调控区、金属蛋白水解酶区、去整合蛋白区、富半胱氨酸区、表皮生长因子区、跨膜区和细胞质区组成,已发现30多种成员。它们在性细胞发生、受精、胚胎发育、细胞融合、器官形成、细胞分化等方面起重要作用。本文重点介绍了ADAM10／Kuz在神经发育过程中的信号传导和蛋白水解酶作用及ADAM17／TACE、ADAMTS在小鼠胚胎发育过程中对眼、肾、肾上腺、生殖等器官结构、功能的作用;另外,还对ADAM12／meltrin α促进肥细胞融合、分化、MIG－17介导细胞迁移等多种ADAMs在生长发育方面的研究作了简要介绍。     

哺乳动物卵母细胞成熟和受精中细胞骨架重组和作用

卵母细胞成熟和受精是动物生殖过程的核心环节。细胞骨架是遍布于卵母细胞胞质中的一种复杂的蛋白质纤维网络,研究表明,卵母细胞成熟和受精过程中伴随着广泛的胞质骨架重组。哺乳动物卵母细胞和早期胚胎中细胞骨架具有其独特的分布和功能,使卵母细胞和胚胎呈现出不同的变化特点。微丝、微管的分布变化与卵母细胞成熟和受精中遗传物质的重组密切相关。近年来,对哺乳动物不同物种间卵母细胞和胚胎中细胞骨架成分的研究取得了很大的进展,结合这些研究成果,对哺乳动物卵母细胞成熟和受精过程中细胞骨架的重组、分布和作用进行了介绍。同时,对多种信号转导途径参与卵母细胞成熟和受精中细胞骨架系统的调控也作了探讨。     

人及哺乳动物受精与糖蛋白的关系

越来越多的研究表明精卵识别与精子质膜及卵透明带中所含糖蛋白有直接关系。在精卵识别中存在着精子受体和卵透明带（zona pellucida,ZP）配体相互作用的糖类识别机制及精子质膜与卵子质膜的糖蛋白识别。本文主要从结构功能上对与受精相关的精卵表面糖蛋白作一介绍。卵子表面受精相关的糖蛋白主要是ZP1、ZP2、ZP3。与卵子表面糖蛋白相比,精子表面参与精卵识别的糖蛋白种类较多,在SP56、SP95、PH－20、FA－1、甘露糖结合蛋白、顶体素、fertilin蛋白等。     

ADAMs的结构和功能简介

ADAMs(a disintegrin and metallopoteinase）是近几年在细胞中发现的一类含有多个功能区的膜蛋白。本文简要介绍了ADAMs的结构和功能,为国内进行有关方面的研究提供了初步资料。     

Membrane interactions of the putative fusion peptide (MFalphaP) from fertilin-alpha,the mouse sperm protein complex involved in fertilization

Mammalian fertilization depends upon successful binding and fusion between the membranes of the spermatozoon and the oocyte. These processes are thought to be mediated by a series of protein-protein interactions in which sperm antigens known as fertilins are thought to play a key role. Using a recently developed fluorescence technique, the interactions of the oligopeptide sequence corresponding to the fusogenic domain of mouse fertilin-alpha (MFalphaP) and phospholipid vesicles have been investigated. Following stopped-flow mixing, MFalphaP bound rapidly to phospholipid membranes in a co-operative manner with a Hill coefficient of 2.4 and binding rate constants in excess of 1000 s-1. The co-operative nature of the binding process is suggested to represent evidence of a structural mechanism to prevent egg fertilization by immature spermatozoa. The subsequent membrane insertion was found to take place over a longer time period (with rate constants of up to 6.3 s-1), and was linear with respect to peptide concentration. Comparison of these processes with similar time-resolved circular dichroism measurements revealed that changes in peptide secondary structure were very rapid. Fourier transform infrared spectroscopy measurements confirmed changes in the secondary structure of MFalphaP during interaction with PC phospholipid membranes, indicating that the peptide is mainly present in a beta-structure with a small proportion of alpha-helix. These results are consistent with the hypothesis that fertilin-alpha is the fusogenic species with an important role in fertilization.     

TGFβ induces proHB-EGF shedding and EGFR transactivation through ADAM activation in gastric cancer cells

Background and aims: Transforming growth factor-beta (TGFβ) is known to potently inhibit cell growth. Loss of responsiveness to TGFβ inhibition on cell growth is a hallmark of many types of cancer, yet its mechanism is not fully understood. Membrane-anchored heparin-binding EGF-like growth factor (proHB-EGF) ectodomain is cleaved by a disintegrin and metalloproteinase (ADAM) members and is implicated in epidermal growth factor receptor (EGFR) transactivation. Recently, nuclear translocation of the C-terminal fragment (CTF) of pro-HB-EGF was found to induce cell growth. We investigated the association between TGFβ and HB-EGF signal transduction via ADAM activation.Materials and methods: The CCK-8 assay in two gastric cancer cell lines was used to determine the effect for cell growth by TGFβ. The effect of two ADAM inhibitors was also evaluated. Induction of EGFR phosphorylation by TGFβ was analyzed and the effect of the ADAM inhibitors was also examined. Nuclear translocation of HB-EGF-CTF by shedding through ADAM activated by TGFβ was also analyzed. EGFR transactivation, HB-EGF-CTF nuclear translocation, and cell growth were examined under the condition of ADAM17 knockdown.Result: TGFβ-induced EGFR phosphorylation of which ADAM inhibitors were able to inhibit. TGFβ induced shedding of proHB-EGF allowing HB-EGF-CTF to translocate to the nucleus. ADAM inhibitors blocked this nuclear translocation. TGFβ enhanced gastric cancer cell growth and ADAM inhibitors suppressed this effect. EGFR phosphorylation, HB-EGF-CTF nuclear translocation, and cell growth were suppressed in ADAM17 knockdown cells.Conclusion: HB-EGF-CTF nuclear translocation and EGFR transactivation from proHB-EGF shedding mediated by ADAM17 activated by TGFβ might be an important pathway of gastric cancer cell proliferation by TGFβ.     

ADAM的遗传和进化

ADAM,又称MDC,分别是去整合蛋白和金属蛋白水解酶（a disintegrin and metalloproteinase,ADAM）及金属蛋白水解酶、去整合蛋白和富半胱氨酸（metalloproteinase/disintegrin/cysteine-rich,MDC）的英文缩写,是近几年在多细胞动物中发现的一类含信号肽区、前调控区、金属蛋白水解酶区、去整合蛋白区、富半胱氨酸区、上皮生长因子区、跨膜区和胞内区的细胞表面糖蛋白,本文简要总结了有关ADAM起源、遗传、进化和亲缘关系的研究结果。Abstract:ADAM (a disintegrin and metalloproteinase),or named MDC (metalloproteinase/disintegrin/cysteine-rich) is a family of glycoproteins in cell surface,which was found in recent years and consists of a signal peptide,a propetide,a metalloproteinase,a disintegrin,a cysteine-rich domain,and an epidermal growth factor (EGF)-like domain,a transmembrane region,and a cytoplasmic tail.The research results about their origin,heredity,evolution and evolutionary relationship are summaried in this paper.     

靶向ADAM17基因RNA干扰慢病毒载体的构建及慢病毒包装

目的构建靶向ADAM17基因RNA干扰（RNAi）慢病毒载体及包装慢病毒。方法根据人ADAM17mRNA序列设计4个靶序列,合成4对寡核苷酸序列,同时合成1对阴性对照寡核苷酸序列;将以上5对寡核苷酸序列退火后连入pLVTHM质粒,经酶切和测序鉴定。将重组慢病毒质粒转染至A549细胞,以Real-time PCR检测A549细胞中ADAM17 mRNA表达。将干扰效果最佳的质粒载体和包装质粒共转染至293T细胞,包装产生病毒颗粒。以流式细胞术检测重组慢病毒的滴度。结果酶切和测序证实干扰靶序列已被准确克隆到pLVTHM质粒载体。pLVTHM-ADAM17-siRNA1-4均可显著抑制A549细胞ADAM17 mRNA的表达,其中pLVTHM-ADAM17-siRNA4的抑制效果最佳。LV-ADAM17-siRNA4重组慢病毒的滴度为2.16×108TU/ml。结论成功构建了靶向人ADAM17基因RNAi慢病毒载体及包装了重组慢病毒。     

含凝血酶敏感素1型基序的解聚素样金属蛋白酶在冠心病中作用的研究进展

含凝血酶敏感素1型基序的解聚素样金属蛋白酶(a disintegrin and metalloproteinase with thrombospondin motifs 1,ADAMTS-1)可降解细胞外基质中的多能蛋白聚糖,促进平滑肌细胞的迁移,参与动脉粥样硬化的发生,并能进一步活化粥样斑块,促进斑块破裂;还可抑制血管的新生、参与胶原代谢加速心室重构、心肌纤维化等病理过程的进展,与各种类型的冠心痛如稳定型心绞痛(stable angina,SA)、急性冠脉综合征(acute coronary syndrome,ACS)、缺血性心肌病(ischemic cardiomyopathy,ICM)均密切相关.研究表明,ADAMTS-1有助于冠脉狭窄程度评估、斑块稳定性判断、ACS的辅助诊断及治疗策略的选择,有望用于冠心病的危险分层和预后评估,并可能成为动脉粥样硬化和各种类型冠心病预防和治疗的新靶点.本文将就ADAMTS-1在冠心病中作用的研究进展进行综述.