Fallon Ann M, Carroll Elissa M
Department of Entomology, University of Minnesota, 1980 Folwell Ave., St. Paul, MN 55108, USA.
Insects. 2023 Jun 2;14(6):516. doi: 10.3390/insects14060516.
are obligate intracellular bacteria that occur in insects and filarial worms. Strains that infect insects have genomes that encode mobile genetic elements, including diverse lambda-like prophages called Phage WO. Phage WO packages an approximately 65 kb viral genome that includes a unique eukaryotic association module, or EAM, that encodes unusually large proteins thought to mediate interactions between the bacterium, its virus, and the eukaryotic host cell. The supergroup B strain, Stri from the planthopper , produces phage-like particles that can be recovered from persistently infected mosquito cells by ultracentrifugation. Illumina sequencing, assembly, and manual curation of DNA from two independent preparations converged on an identical 15,638 bp sequence that encoded packaging, assembly, and structural proteins. The absence of an EAM and regulatory genes defined for Phage WO from the wasp, was consistent with the possibility that the 15,638 bp sequence represents an element related to a gene transfer agent (GTA), characterized by a signature head-tail region encoding structural proteins that package host chromosomal DNA. Future investigation of GTA function will be supported by the improved recovery of physical particles, electron microscopic examination of potential diversity among particles, and rigorous examination of DNA content by methods independent of sequence assembly.
是存在于昆虫和丝虫中的专性细胞内细菌。感染昆虫的菌株具有编码可移动遗传元件的基因组，包括多种称为噬菌体WO的类λ原噬菌体。噬菌体WO包装一个约65 kb的病毒基因组，其中包括一个独特的真核生物关联模块，即EAM，它编码被认为介导细菌、其病毒和真核宿主细胞之间相互作用的异常大的蛋白质。来自飞虱的超群B菌株Stri产生噬菌体样颗粒，可通过超速离心从持续感染的蚊子细胞中回收。对来自两个独立制备物的DNA进行Illumina测序、组装和人工编辑，得到了一个相同的15638 bp序列，该序列编码包装、组装和结构蛋白。黄蜂中不存在为噬菌体WO定义的EAM和调控基因，这与15638 bp序列代表与基因转移因子（GTA）相关的元件的可能性一致，GTA的特征是具有一个编码包装宿主染色体DNA的结构蛋白的标志性头尾区域。通过改进物理颗粒的回收、电子显微镜检查颗粒间潜在的多样性以及通过独立于序列组装的方法严格检查DNA含量，将为未来对GTA功能的研究提供支持。
