先导编辑（prime editing）为何被称为「搜索-替换」式编辑，其 pegRNA 起了什么作用？
Why is prime editing described as a search-and-replace editor, and what role does its pegRNA play?
先导编辑利用融合逆转录酶的 nickase Cas9 与一种特殊 pegRNA，后者同时携带引导序列和编码预期编辑的逆转录模板。Cas9 在靶链切开单链后，逆转录酶以 pegRNA 的模板合成含所需突变的 DNA flap，再经细胞修复将修正整合进基因组，可在不引入双链断裂的情况下实现小片段插入、删除和所有 12 种碱基转换。
Prime editing uses a nickase Cas9 fused to reverse transcriptase together with a prime editing guide RNA (pegRNA) that carries both a targeting spacer and a reverse-transcription template encoding the desired edit. After Cas9 nicks one strand, the reverse transcriptase synthesizes a DNA flap containing the change from the pegRNA template, and cellular repair integrates it, enabling insertions, deletions and all 12 base-to-base conversions without double-strand breaks.
难度 专业 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
Anzalone AV et al. Search-and-replace genome editing without double-strand breaks or donor DNA. Nature (2019) 576:149-157
Anzalone AV et al. Search-and-replace genome editing without double-strand breaks or donor DNA. Nature (2019) 576:149-157
独立核验依据 · Independent verification: 核验依据 1 DOI 10.3410/f.736778482.793566505
#先导编辑 #pegRNA #逆转录酶 #精准编辑
CAR-T 细胞疗法为何被视作合成生物学的临床应用范例，其人工受体如何工作？
Why is CAR-T cell therapy considered a clinical application of synthetic biology, and how does its engineered receptor work?
CAR-T 通过病毒载体把编码嵌合抗原受体的基因导入患者 T 细胞，该受体将肿瘤识别域与 T 细胞激活域人工拼接，使细胞无需 MHC 提呈即可识别表面抗原。这种「即插即用」的受体设计正是合成生物学模块化装配思路的体现，已用于血液肿瘤治疗。
In CAR-T therapy, a viral vector introduces a gene encoding a chimeric antigen receptor into a patient's T cells; the receptor artificially fuses a tumor-recognition domain with T-cell activation domains so cells detect surface antigens without MHC presentation. This plug-and-play receptor design reflects synthetic biology's modular assembly and is already used against blood cancers.
难度 专业 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#CAR-T #嵌合抗原受体 #细胞疗法 #合成生物学应用
CRISPR-Cas9 系统实现精准基因组编辑，其核心的分子机制包含哪几个关键步骤？
What are the key molecular steps by which the CRISPR-Cas9 system achieves precise genome editing?
系统首先由 sgRNA 引导 Cas9 蛋白通过 PAM 序列识别靶 DNA 并解旋形成 R-loop。随后 Cas9 的两个核酸酶结构域 HNH 与 RuvC 分别在两条链上切开磷酸二酯键，产生双链断裂。细胞随后通过非同源末端连接或同源定向修复引入插入缺失或精确替换。
The system first uses a single-guide RNA to direct Cas9 to the target DNA, where the PAM sequence enables strand separation and R-loop formation. Cas9's two nuclease domains, HNH and RuvC, then cleave opposite DNA strands to create a double-strand break. The cell subsequently repairs the break by non-homologous end joining or homology-directed repair, yielding indels or precise edits.
难度 专业 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#CRISPR #基因编辑 #Cas9 #同源修复
病毒载体如何用于基因治疗？
How are viral vectors used in gene therapy?
改造后的病毒（如AAV、慢病毒）去掉致病部分、装入正常基因，把治疗基因送入患者细胞以弥补缺陷，用于治疗部分遗传病。
Engineered viruses (e.g. AAV, lentivirus) are stripped of disease genes and loaded with a normal gene to deliver therapy into patient cells, treating some genetic disorders.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#基因治疗 #病毒载体 #AAV
与传统 CRISPR-Cas9 造成双链断裂不同，碱基编辑器如何实现不依赖双链断裂的单碱基替换？
Unlike conventional CRISPR-Cas9 which creates double-strand breaks, how do base editors achieve single-base substitution without such breaks?
碱基编辑器将失活的 Cas9 或切口酶与脱氨酶融合，由 sgRNA 定位到靶位点。脱氨酶直接在单链 DNA 上将胞嘧啶或腺嘌呤化学转化为另一种碱基，再由细胞修复机制固定为永久替换，从而避免双链断裂带来的插入缺失风险。
A base editor fuses a catalytically impaired Cas9 or nickase with a deaminase and is guided by sgRNA to the target site. The deaminase chemically converts cytosine or adenine to another base on the single-stranded DNA, and cellular repair fixes the change as a permanent substitution, avoiding the indels caused by double-strand breaks.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
Komor AC et al. Programmable editing of a target base in genomic DNA without double-stranded DNA cleavage. Nature (2016) 533:420-424
Komor AC et al. Programmable editing of a target base in genomic DNA without double-stranded DNA cleavage. Nature (2016) 533:420-424
独立核验依据 · Independent verification: 核验依据 1 DOI 10.1038/nature17946
#碱基编辑 #单碱基编辑 #脱氨酶 #基因修正
何为「正交」基因线路，设计正交系统的意义是什么？
What is an orthogonal genetic circuit, and why is designing such systems meaningful?
正交线路使用与宿主天然生物分子互不干扰的 DNA、RNA 或蛋白质部件，使其调控行为独立于细胞原有网络。这样可减少串扰与意外反馈，让工程师在活细胞内可靠地叠加多个独立功能模块。
An orthogonal circuit uses DNA, RNA or protein parts that do not cross-talk with the host's native molecules, so its behavior is independent of the cell's existing networks. This reduces interference and unexpected feedback, letting engineers reliably layer multiple independent functional modules inside living cells.
难度 进阶 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#正交系统 #合成线路 #模块化 #减少串扰
合成生物学中「基因线路」指的是什么，通常由哪些标准化的 DNA 元件构成？
What is meant by a genetic circuit in synthetic biology, and which standardized DNA parts typically compose it?
基因线路是由启动子、核糖体结合位点、编码序列和终止子等标准生物元件组装而成的调控网络，能把输入信号转化为可测量的输出，如蛋白质表达或荧光。工程师借助 BioBrick 等标准化部件库，像搭积木一样构建逻辑门、振荡器和传感器。
A genetic circuit is a regulatory network assembled from standardized parts such as promoters, ribosome-binding sites, coding sequences and terminators, which converts input signals into measurable outputs such as protein expression or fluorescence. Using libraries like BioBrick, engineers build logic gates, oscillators and sensors in a modular way.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#合成生物学 #基因线路 #标准生物元件 #逻辑门
CRISPR可以怎样用于基因治疗？
How can CRISPR be used in gene therapy?
CRISPR-Cas9像分子剪刀，可在基因组特定位置切断并修正致病突变，或敲除有害基因，为遗传性疾病的精准治疗提供工具。
CRISPR-Cas9 acts like molecular scissors to cut and correct disease-causing mutations at precise sites, or knock out harmful genes, enabling precise treatment of inherited diseases.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#CRISPR #基因编辑 #治疗
脱靶效应是 CRISPR 编辑的主要风险之一，研究者常用哪些实验方法评估脱靶位点？
Off-target effects are a major risk of CRISPR editing; what experimental methods do researchers commonly use to assess off-target sites?
常用方法包括 GUIDE-seq、CIRCLE-seq 和 Digenome-seq 等，它们通过体外或体内标记 Cas9 切割位点后测序，全基因组地发现潜在的脱靶位置。此外，计算工具先预测候选位点，再用高保真测序或报告系统验证实际编辑频率。
Common approaches such as GUIDE-seq, CIRCLE-seq and Digenome-seq tag and sequence Cas9 cleavage sites genome-wide to reveal potential off-target locations in vitro or in cells. Computational tools first predict candidate sites, which are then validated for actual editing frequency by high-fidelity sequencing or reporter assays.
难度 进阶 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
Tsai SQ et al. GUIDE-seq enables genome-wide profiling of off-target cleavage by CRISPR-Cas nucleases. Nature Biotechnology (2015) 33:187-197
Tsai SQ et al. GUIDE-seq enables genome-wide profiling of off-target cleavage by CRISPR-Cas nucleases. Nature Biotechnology (2015) 33:187-197
独立核验依据 · Independent verification: 核验依据 1 DOI 10.1038/nbt.3117
#脱靶效应 #GUIDE-seq #全基因组评估 #编辑安全性
在 CRISPR 应用中，sgRNA（单链向导 RNA）承担什么功能？
In CRISPR applications, what function does the single-guide RNA (sgRNA) perform?
sgRNA 由 CRISPR RNA 与 trans-activating RNA 融合而成，其约 20 个核苷酸的引导序列决定靶标特异性，与 Cas9 结合后带其找到互补的 DNA 序列。它同时包含与 Cas9 结合的结构骨架，使单一分子同时完成靶向与定位。
The sgRNA fuses the CRISPR RNA and trans-activating RNA into one molecule; its roughly 20-nucleotide spacer determines target specificity and, together with Cas9, directs the complex to the complementary DNA. It also contains the scaffold that binds Cas9, so a single molecule handles both targeting and localization.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#sgRNA #向导 RNA #靶向 #Cas9 复合物