这项最新的研究突出强调了一种学习CRISPR系统如何工作的方法以及一种潜在的开展基于CRISPR的基因编辑的附加工具。相关研究结果于2016年6月13日在线发表在Nature Microbiology期刊上，论文标题为“Inactivation of CRISPR-Cas systems by anti-CRISPR proteins in diverse bacterial species”。
2013年，Davidson团队在一项研究中，发现铜绿假单胞菌（Pseudomonas aeruginosa）基因组中的单个原噬菌体能够抵抗一系列其他类型的噬菌体（Nature,17 January 2013, doi:10.1038/nature11723）。因此，他们对铜绿假单胞菌CRISPR系统进行调整以便试图理解这种原噬菌体如何可能影响这种细菌对噬菌体感染的敏感性。他们发现铜绿假单胞菌的I-F型CRISPR系统仅仅阻止某些类型的噬菌体的感染。通过搜寻噬菌体基因组，他们发现5种独特的基因，每种都有抗CRISPR活性。在随后的一项研究中，Davidson团队鉴定出另外4种基因，它们表现出抗铜绿假单胞菌I-F型CRISPR系统的活性（mBio, 15 April 2014, doi: 10.1128/mBio.00896-14）。
Davidson告诉《科学家》杂志，“存在许多种不同抗CRISPR基因家族表明这些基因对噬菌体是有益处的，以及CRISPR系统是噬菌体感染的一种重要的阻碍物。”Davidson团队在之前的一项研究中鉴定出的三种抗CRISPR蛋白在体外测试时以一种不同的方式结合到CRISPR系统上并阻断它的功能（Nature, 01 October 2015, doi:10.1038/nature15254）。
Inactivation of CRISPR-Cas systems by anti-CRISPR proteins in diverse bacterial species
CRISPR-Cas systems provide sequence-specific adaptive immunity against foreign nucleic acids1,2. They are present in approximately half of all sequenced prokaryotes3 and are expected to constitute a major barrier to horizontal gene transfer. We previously described nine distinct families of proteins encoded in Pseudomonas phage genomes that inhibit CRISPR-Cas function4,5. We have developed a bioinformatic approach that enabled us to discover additional anti-CRISPR proteins encoded in phages and other mobile genetic elements of diverse bacterial species. We show that five previously undiscovered families of anti-CRISPRs inhibit the type I-F CRISPR-Cas systems of both Pseudomonas aeruginosa and Pectobacterium atrosepticum, and a dual specificity anti-CRISPR inactivates both type I-F and I-E CRISPR-Cas systems. Mirroring the distribution of the CRISPR-Cas systems they inactivate, these anti-CRISPRs were found in species distributed broadly across the phylum Proteobacteria. Importantly, anti-CRISPRs originating from species with divergent type I-F CRISPR-Cas systems were able to inhibit the two systems we tested, highlighting their broad specificity. These results suggest that all type I-F CRISPR-Cas systems are vulnerable to inhibition by anti-CRISPRs. Given the widespread occurrence and promiscuous activity of the anti-CRISPRs described here, we propose that anti-CRISPRs play an influential role in facilitating the movement of DNA between prokaryotes by breaching the barrier imposed by CRISPR-Cas systems.