Ruden Douglas M
Department of Obstetrics and Gynecology, C. S. Mott Center for Human Growth and Development, Institute of Environmental Health Sciences, Wayne State University, Detroit, MI 48201, USA.
Genes (Basel). 2025 Jul 28;16(8):896. doi: 10.3390/genes16080896.
The recent discovery of TIGR-Tas (Tandem Interspaced Guide RNA-Targeting Systems) marks a major advance in the field of genome editing, introducing a new class of compact, programmable DNA-targeting systems that function independently of traditional CRISPR-Cas pathways. TIGR-Tas effectors use a novel dual-spacer guide RNA (tigRNA) to recognize both strands of target DNA without requiring a protospacer adjacent motif (PAM). These Tas proteins introduce double-stranded DNA cuts with characteristic 8-nucleotide 3' overhangs and are significantly smaller than Cas9, offering delivery advantages for in vivo editing. Structural analyses reveal homology to box C/D snoRNP proteins, suggesting a previously unrecognized evolutionary lineage of RNA-guided nucleases. This review positions TIGR-Tas at the forefront of a new wave of RNA-programmable genome-editing technologies. In parallel, I provide comparative insight into the diverse and increasingly modular CRISPR-Cas systems, including Cas9, Cas12, Cas13, and emerging effectors like Cas3, Cas10, CasΦ, and Cas14. While the CRISPR-Cas universe has revolutionized molecular biology, TIGR-Tas systems open a complementary and potentially more versatile path for programmable genome manipulation. I discuss mechanistic distinctions, evolutionary implications, and potential applications in human cells, synthetic biology, and therapeutic genome engineering.
TIGR-Tas（串联间隔引导RNA靶向系统）的最新发现标志着基因组编辑领域的一项重大进展，引入了一类新型的紧凑、可编程的DNA靶向系统，其功能独立于传统的CRISPR-Cas途径。TIGR-Tas效应器使用一种新型的双间隔引导RNA（tigRNA）来识别目标DNA的两条链，而无需原间隔相邻基序（PAM）。这些Tas蛋白会引入具有特征性8个核苷酸3'突出端的双链DNA切割，并且比Cas9小得多，为体内编辑提供了递送优势。结构分析揭示了与盒C/D snoRNP蛋白的同源性，表明存在一种以前未被认识的RNA引导核酸酶的进化谱系。这篇综述将TIGR-Tas置于新一轮RNA可编程基因组编辑技术的前沿。同时，我对包括Cas9、Cas12、Cas13以及如Cas3、Cas10、CasΦ和Cas14等新兴效应器在内的多样且日益模块化的CRISPR-Cas系统提供了比较性见解。虽然CRISPR-Cas领域已经彻底改变了分子生物学，但TIGR-Tas系统为可编程基因组操作开辟了一条互补且可能更具通用性的途径。我讨论了其机制差异、进化意义以及在人类细胞、合成生物学和治疗性基因组工程中的潜在应用。
