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软件汇总
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数据汇总
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论文汇总
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Overview The Human Immunodeficiency Virus, also known as HIV, is a retrovirus responsible for impairing the human immune system. This virus attacks and gradually destroys the human immune system, leaving the host unprotected upon infection. Those who become infected with HIV and eventually die often succumb to secondary infections or cancers. AIDS (Acquired Immunodeficiency Syndrome) represents the final stage of an HIV infection.
Morphological Structure The Human Immunodeficiency Virus has a diameter of approximately 80-140 nanometers, appearing round or oval-shaped. The virus has a lipid envelope derived from the host cell, embedded with the viral proteins gp120 and gp41. Of these, gp41 is a transmembrane protein, and gp120 is surface-bound, connected to gp41 through non-covalent interactions. Inside is a spherical matrix formed by the p17 protein, a conical capsid formed by the p24 protein, which appears as high electron density under an electron microscope. The capsid contains the virus's RNA genome, enzymes (reverse transcriptase, integrase, protease), and other components from the host cell, such as tRNAlys3, which acts as a primer for reverse transcription. The viral surface envelope has increased electron density and visible rod-shaped protrusions. Fragmented, incomplete virions are common, with envelopes losing integrity. The fragmented virus appears as segmented or twisted amongst intact virions.
coding genes The HIV genome consists of two identical positive-strand RNAs, about 9.7 kilobase pairs (kb) in length, wrapped in a viral protein shell. Around the nucleocapsid is a phospholipid bilayer derived from the host cell membrane, including virally encoded membrane proteins. The genome has long terminal repeats at both ends, playing a regulatory role in viral gene integration, expression, and replication. The genome contains three structural genes (gag, pol, and env), two regulatory genes (tat and rev), and four accessory genes (nef, vpr, vpu, and vif). The gag gene codes for core proteins; the env gene for two essential glycoproteins, envelope glycoproteins gp120 and gp41; and the pol gene for essential replication enzymes, including reverse transcriptase, integrase, and viral protease. Due to the lack of proofreading by reverse transcriptase, random mutations occur, with high in-virus replication rates and recombination between viral DNA and host DNA. This leads to drug resistance and makes HIV highly mutable, with the env gene most prone to mutation. HIV-2 and HIV-1 have significant nucleotide sequence differences, only about 40%-50% similarity. Their gene structures are essentially the same, but HIV-2 lacks the vpu gene and has the vpx gene. The predominant strain of HIV in China is HIV-1, with 10 subtypes identified, mainly being the AE and BC recombinants.
Subtypes The virus has two main types: HIV-1 and HIV-2. HIV-1, originating from the Congo Basin region in Africa, is the most prevalent strain worldwide and is responsible for approximately 95% of all HIV infections. HIV-2 is primarily found in West Africa, though it also affects a minority in Europe, India, and the US. HIV-2 is less contagious and takes longer to develop into AIDS. Even though non-nucleoside reverse transcriptase inhibitors (like Nevirapine and Efavirenz) are ineffective against HIV-2, it's essential for those infected with HIV-2 to receive treatment. More information about HIV-2 is available on another page. HIV-1 is further subdivided into four groups; M, N, O, and P, with Group M being the most widespread. Group M is divided into nine subtypes: A, B, C, D, F, G, H, J, and K. A brief overview of the nine HIV genes:
- gag gene: Encodes for the HIV core protein (p24), capsid protein (p17), and ribonucleotide reductase (p7).
- pol gene: Encodes the virus reverse transcriptase, RNase H, and protease.
- env gene: Encodes for the virus's surface proteins (gp120 and gp41), which bind to the host cell's CD4 and co-receptors, facilitating HIV entry.
- tat gene: Encodes the viral transcription activation protein (Tat), essential for HIV transcription.
- rev gene: Encodes the post-transcriptional regulatory protein (Rev) crucial for subsequent processes after HIV transcription.
- vif gene: Encodes for the viral auxiliary factor (Vif), assisting in viral replication within host cells.
- vpr gene: Encodes the viral protein (Vpr) with multiple roles post-HIV infection.
- vpu gene: Encodes for the viral protein (Vpu) with various roles post-infection.
- nef gene: Encodes the viral protein (Nef), which helps the virus evade the host immune system in multiple ways.
概述
人类免疫缺陷病毒又称艾滋病病毒，是造成人类免疫系统缺陷的一种逆转录病毒。这一病毒会攻击并逐渐破坏人类的免疫系统，致使宿主在被感染时得不到保护。感染人类免疫缺陷病毒并且去世的人，往往死于继发感染或者癌症。而艾滋病是人类免疫缺陷病毒感染的最后阶段。
形态结构
人类免疫缺陷病毒直径约80～140纳米，呈圆形或卵圆形。病毒外膜是类脂包膜，来自宿主细胞，并嵌有病毒的蛋白gp120与gp41。其中gp41是跨膜蛋白，gp120位于表面，与gp41通过非共价作用结合。向内是由蛋白p17形成的球形基质（matrix），以及蛋白p24形成的半锥形衣壳（capsid），衣壳在电镜下呈高电子密度。衣壳内含有病毒的RNA基因组、酶（逆转录酶、整合酶、蛋白酶）以及其他来自宿主细胞的成分（如tRNAlys3，作为逆转录的引物）。
病毒表面囊膜电子致密度增高，并且可见杆棒样表面突起。破碎不完整的毒粒尤为多见，囊膜会失去完整性，碎裂的病毒会呈片段状或者扭结状分散于成团的完整毒粒中。
编码基因
艾滋病病毒的基因组是两条相同的正链RNA，全长约9.7千碱基对（kb），包裹在一个病毒蛋白壳内，核衣壳外周是来源于宿主细胞膜的磷酸脂质双层，也包括病毒编码的膜蛋白。
艾滋病病毒基因组两端长末端重复序列发挥着调节病毒基因整合、表达和病毒复制的作用。基因组含有3个结构基因gag、pol和env，2个调节基因（tat反式激活因子、rev毒粒蛋白表达调节因子），4个辅助基因（nef负调控因子、vpr病毒蛋白r、vpu病毒蛋白和vif病毒感染因子）。其中gag基因序列编码核壳蛋白；env基因序列编码病毒感染细胞所必须的两种糖蛋白，即包膜糖蛋白gp120和gp41；pol基因序列编码病毒复制所必须的酶，即逆转录酶、结合酶和病毒蛋白酶 。
由于反转录酶无校正功能，出现随机变异，病毒体内复制频率高，病毒DNA与宿主DNA间存在基因重组，会出现耐药性。这使得艾滋病病毒成为一种变异性很强的病毒。其各部分基因变异强度不同，其中env基因最容易发生变异。
HIV-2和HIV-1核苷酸序列差异较大，仅有40%～50%相同。但是二者的基因结构基本相同，只是HIV-2没有vpu基因，而存在vpx基因。
我国人类免疫缺陷病毒的主要流行株为HIV-1，目前已发现10种亚型，流行的主要亚型是AE重组型和BC重组型。
分型
该病毒有两种主要类型：HIV-1 和 HIV-2。 HIV-1 起源于非洲刚果盆地周围地区，是全球最流行的毒株。它是造成大约 95% 的所有 HIV 感染的原因。
HIV-2 主要在西非发现，尽管它也影响欧洲、印度和美国的少数人。 HIV-2 的传染性较低，需要较长时间才能发展为艾滋病。尽管非核苷类逆转录酶类的抗逆转录病毒药物（例如奈韦拉平和依非韦伦）对 HIV-2 无效，但 HIV-2 感染者接受治疗仍然很重要。另一个页面上有关于 HIV-2 的更多信息。
HIV-1进一步分为四组； M、N、O 和 P。其中，M 组是世界范围内分布最广的。 M组分为九个不同的亚型； A、B、C、D、F、G、H、J 和 K。
HIV的9个基因的简要概述：
gag基因：编码HIV内核蛋白（p24）、囊膜蛋白（p17）和核糖核酸酶（p7）。
pol基因：编码病毒反转录酶（reverse transcriptase）、核糖核酸酶（RNase H）和病毒蛋白酶（protease）。
env基因：编码病毒的表面蛋白（gp120和gp41），它们与宿主细胞的CD4和共受体结合，介导HIV进入细胞。
tat基因：编码病毒转录激活蛋白（Tat），它在HIV的转录过程中发挥重要作用。
rev基因：编码病毒转录后调节蛋白（Rev），它在HIV转录后的后续过程中发挥重要作用。
vif基因：编码病毒的辅助因子（Vif），它帮助病毒在宿主细胞中复制。
vpr基因：编码病毒蛋白质（Vpr），它在HIV感染宿主细胞后的生命周期中发挥多种作用。
vpu基因：编码病毒蛋白质（Vpu），它在HIV感染宿主细胞后的生命周期中发挥多种作用。
nef基因：编码病毒蛋白质（Nef），它通过多种方式帮助病毒逃避宿主免疫系统的攻击。