1
|
Mohr G, Yao J, Park SK, Markham L, Lambowitz AM. Mechanisms used for cDNA synthesis and site-specific integration of RNA into DNA genomes by a reverse transcriptase-Cas1 fusion protein. SCIENCE ADVANCES 2024; 10:eadk8791. [PMID: 38608016 PMCID: PMC11014452 DOI: 10.1126/sciadv.adk8791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 03/08/2024] [Indexed: 04/14/2024]
Abstract
Reverse transcriptase-Cas1 (RT-Cas1) fusion proteins found in some CRISPR systems enable spacer acquisition from both RNA and DNA, but the mechanism of RNA spacer acquisition has remained unclear. Here, we found that Marinomonas mediterranea RT-Cas1/Cas2 adds short 3'-DNA (dN) tails to RNA protospacers, enabling their direct integration into CRISPR arrays as 3'-dN-RNAs or 3'-dN-RNA/cDNA duplexes at rates comparable to similarly configured DNAs. Reverse transcription of RNA protospacers is initiated at 3' proximal sites by multiple mechanisms, including recently described de novo initiation, protein priming with any dNTP, and use of short exogenous or synthesized DNA oligomer primers, enabling synthesis of near full-length cDNAs of diverse RNAs without fixed sequence requirements. The integration of 3'-dN-RNAs or single-stranded DNAs (ssDNAs) is favored over duplexes at higher protospacer concentrations, potentially relevant to spacer acquisition from abundant pathogen RNAs or ssDNA fragments generated by phage defense nucleases. Our findings reveal mechanisms for site-specifically integrating RNA into DNA genomes with potential biotechnological applications.
Collapse
Affiliation(s)
- Georg Mohr
- Departments of Molecular Biosciences and Oncology, University of Texas at Austin, Austin, TX 78712, USA
| | - Jun Yao
- Departments of Molecular Biosciences and Oncology, University of Texas at Austin, Austin, TX 78712, USA
| | | | - Laura Markham
- Departments of Molecular Biosciences and Oncology, University of Texas at Austin, Austin, TX 78712, USA
| | | |
Collapse
|
2
|
Aviram N, Shilton AK, Lyn NG, Reis BS, Brivanlou A, Marraffini LA. The Cas10 nuclease activity relieves host dormancy to facilitate spacer acquisition and retention during type III-A CRISPR immunity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.11.579731. [PMID: 38405743 PMCID: PMC10888962 DOI: 10.1101/2024.02.11.579731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
A hallmark of CRISPR immunity is the acquisition of short viral DNA sequences, known as spacers, that are transcribed into guide RNAs to recognize complementary sequences. The staphylococcal type III-A CRISPR-Cas system uses guide RNAs to locate viral transcripts and start a response that displays two mechanisms of immunity. When immunity is triggered by an early-expressed phage RNA, degradation of viral ssDNA can cure the host from infection. In contrast, when the RNA guide targets a late-expressed transcript, defense requires the activity of Csm6, a non-specific RNase. Here we show that Csm6 triggers a growth arrest of the host that provides immunity at the population level which hinders viral propagation to allow the replication of non-infected cells. We demonstrate that this mechanism leads to defense against not only the target phage but also other viruses present in the population that fail to replicate in the arrested cells. On the other hand, dormancy limits the acquisition and retention of spacers that trigger it. We found that the ssDNase activity of type III-A systems is required for the re-growth of a subset of the arrested cells, presumably through the degradation of the phage DNA, ending target transcription and inactivating the immune response. Altogether, our work reveals a built-in mechanism within type III-A CRISPR-Cas systems that allows the exit from dormancy needed for the subsistence of spacers that provide broad-spectrum immunity.
Collapse
Affiliation(s)
- Naama Aviram
- Laboratory of Bacteriology, the Rockefeller University, 1230 York Ave, New York, NY 10065, USA
| | - Amanda K Shilton
- Laboratory of Bacteriology, the Rockefeller University, 1230 York Ave, New York, NY 10065, USA
| | - Nia G Lyn
- Laboratory of Bacteriology, the Rockefeller University, 1230 York Ave, New York, NY 10065, USA
| | - Bernardo S Reis
- Laboratory of Mucosal Immunology, the Rockefeller University, 1230 York Ave, New York, NY 10065, USA
| | - Amir Brivanlou
- Laboratory of Bacteriology, the Rockefeller University, 1230 York Ave, New York, NY 10065, USA
| | - Luciano A Marraffini
- Laboratory of Bacteriology, the Rockefeller University, 1230 York Ave, New York, NY 10065, USA
- Howard Hughes Medical Institute, The Rockefeller University, 1230 York Ave, New York, NY 10065, USA
| |
Collapse
|
3
|
Mohr G, Yao J, Park SK, Markham LM, Lambowitz AM. Mechanisms used for cDNA synthesis and site-specific integration of RNA into DNA genomes by a reverse transcriptase-Cas1 fusion protein. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.01.555893. [PMID: 37693417 PMCID: PMC10491204 DOI: 10.1101/2023.09.01.555893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Reverse transcriptase-Cas1 (RT-Cas1) fusion proteins found in some CRISPR systems enable spacer acquisition from both RNA and DNA, but the mechanism of RNA spacer acquisition has remained unclear. Here, we found Marinomonas mediterranea RT-Cas1/Cas2 adds short 3'-DNA (dN) tails to RNA protospacers enabling their direct integration into CRISPR arrays as 3'-dN-RNA/cDNA duplexes or 3'-dN-RNAs at rates comparable to similarly configured DNAs. Reverse transcription of RNA protospacers occurs by multiple mechanisms, including recently described de novo initiation, protein priming with any dNTP, and use of short exogenous or synthesized DNA oligomer primers, enabling synthesis of cDNAs from diverse RNAs without fixed sequence requirements. The integration of 3'-dN-RNAs or single-stranded (ss) DNAs is favored over duplexes at higher protospacer concentrations, potentially relevant to spacer acquisition from abundant pathogen RNAs or ssDNA fragments generated by phage-defense nucleases. Our findings reveal novel mechanisms for site-specifically integrating RNA into DNA genomes with potential biotechnological applications.
Collapse
Affiliation(s)
- Georg Mohr
- Departments of Molecular Biosciences and Oncology University of Texas at Austin Austin TX, 78712
| | - Jun Yao
- Departments of Molecular Biosciences and Oncology University of Texas at Austin Austin TX, 78712
| | | | - Laura M. Markham
- Departments of Molecular Biosciences and Oncology University of Texas at Austin Austin TX, 78712
| | - Alan M. Lambowitz
- Departments of Molecular Biosciences and Oncology University of Texas at Austin Austin TX, 78712
| |
Collapse
|
4
|
Malla RR, Middela K. CRISPR-Based Approaches for Cancer Immunotherapy. Crit Rev Oncog 2023; 28:1-14. [PMID: 38050977 DOI: 10.1615/critrevoncog.2023048723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR) technology is a powerful gene editing tool that has the potential to revolutionize cancer treatment. It allows for precise and efficient editing of specific genes that drive cancer growth and progression. CRISPR-based approaches gene knock-out, which deletes specific genes or sequences of DNA within a cancer cell, and gene knock-in, which inserts new sequences of DNA into a cancer cell to identify potential targets for cancer therapy. Further, genome-wide CRISPR-Cas9-based screens identify specific markers for diagnosis of cancers. Recently, immunotherapy has become a highly efficient strategy for the treatment of cancer. The use of CRISPR in cancer immunotherapy is focused on enhancing the function of T cells, making them more effective at attacking cancer cells and inactivating the immune evasion mechanisms of cancer cells. It has the potential to generate CAR-T cells, which are T cells that have been genetically engineered to target and attack cancer cells specifically. This review uncovers the latest developments in CRISPR-based gene editing strategies and delivery of their components in cancer cells. In addition, the applications of CRISPR in cancer immune therapy are discussed. Overall, this review helps to explore the potential of CRISPR-based strategies in cancer immune therapy in clinical settings.
Collapse
Affiliation(s)
- Rama Rao Malla
- Cancer Biology Laboratory, Department of Biochemistry and Bioinformatics, School of Science, Gandhi Institute of Technology and Management (GITAM) (Deemed to be University), Visakhapatnam-530045, Andhra Pradesh, India; Department of Biochemistry and Bioinformatics, School of Science, GITAM (Deemed to be University), Visakhapatnam-530045, Andhra Pradesh, India
| | - Keerthana Middela
- Department of Biochemistry and Bioinformatics, School of Science, GITAM (Deemed to be University), Visakhapatnam-530045, Andhra Pradesh, India
| |
Collapse
|
5
|
Zhang X, An X. Adaptation by Type III CRISPR-Cas Systems: Breakthrough Findings and Open Questions. Front Microbiol 2022; 13:876174. [PMID: 35495695 PMCID: PMC9048733 DOI: 10.3389/fmicb.2022.876174] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 03/03/2022] [Indexed: 12/26/2022] Open
Abstract
CRISPR-Cas systems acquire heritable defense memory against invading nucleic acids through adaptation. Type III CRISPR-Cas systems have unique and intriguing features of defense and are important in method development for Genetics research. We started to understand the common and unique properties of type III CRISPR-Cas adaptation in recent years. This review summarizes our knowledge regarding CRISPR-Cas adaptation with the emphasis on type III systems and discusses open questions for type III adaptation studies.
Collapse
Affiliation(s)
- Xinfu Zhang
- Department of Biochemistry and Molecular Biology, The University of Georgia, Athens, GA, United States
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, National Engineering Research Center of Tree breeding and Ecological Remediation, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, China
- *Correspondence: Xinfu Zhang,
| | - Xinmin An
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, National Engineering Research Center of Tree breeding and Ecological Remediation, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, China
- Xinmin An,
| |
Collapse
|
6
|
Lee H, Sashital DG. Creating memories: molecular mechanisms of CRISPR adaptation. Trends Biochem Sci 2022; 47:464-476. [DOI: 10.1016/j.tibs.2022.02.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 02/06/2022] [Accepted: 02/07/2022] [Indexed: 12/22/2022]
|
7
|
Aviram N, Thornal AN, Zeevi D, Marraffini LA. Different modes of spacer acquisition by the Staphylococcus epidermidis type III-A CRISPR-Cas system. Nucleic Acids Res 2022; 50:1661-1672. [PMID: 35048966 PMCID: PMC8860600 DOI: 10.1093/nar/gkab1299] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 12/15/2021] [Accepted: 01/06/2022] [Indexed: 12/23/2022] Open
Abstract
CRISPR-Cas systems provide prokaryotic organisms with an adaptive defense mechanism that acquires immunological memories of infections. This is accomplished by integration of short fragments from the genome of invaders such as phages and plasmids, called ‘spacers’, into the CRISPR locus of the host. Depending on their genetic composition, CRISPR-Cas systems can be classified into six types, I-VI, however spacer acquisition has been extensively studied only in type I and II systems. Here, we used an inducible spacer acquisition assay to study this process in the type III-A CRISPR-Cas system of Staphylococcus epidermidis, in the absence of phage selection. Similarly to type I and II spacer acquisition, this type III system uses Cas1 and Cas2 to preferentially integrate spacers from the chromosomal terminus and free dsDNA ends produced after DNA breaks, in a manner that is enhanced by the AddAB DNA repair complex. Surprisingly, a different mode of spacer acquisition from rRNA and tRNA loci, which spans only the transcribed sequences of these genes and is not enhanced by AddAB, was also detected. Therefore, our findings reveal both common mechanistic principles that may be conserved in all CRISPR-Cas systems, as well as unique and intriguing features of type III spacer acquisition.
Collapse
Affiliation(s)
- Naama Aviram
- Laboratory of Bacteriology, the Rockefeller University, 1230 York Ave, New York, NY 10065, USA
| | - Ashley N Thornal
- Laboratory of Bacteriology, the Rockefeller University, 1230 York Ave, New York, NY 10065, USA
| | - David Zeevi
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Luciano A Marraffini
- Laboratory of Bacteriology, the Rockefeller University, 1230 York Ave, New York, NY 10065, USA.,Howard Hughes Medical Institute, The Rockefeller University, 1230 York Ave, New York, NY 10065, USA
| |
Collapse
|