Kanda, R. | Search bioRxiv

bioRxiv2025

Novel Endogenous Retrovirus in the Slow Loris

Endogenous retroviruses (ERVs) are the result of an exogenous infectious retrovirus becoming integrated within the host genome through infection of germline cells. The majority of ERV research has been conducted on humans and other great apes and research of them within other primates can provide unique insights. Screening the genome of two endangered slow lorises Nycticebus bengalensis and N. coucang with a previously identified LTR, a novel ERV was identified within their genomes with varying levels of completeness and numerous solo LTRs. Phylogenetic analysis of the genes of this ERV indicates that it is a betaretrovirus most closely related to HERV-K. Despite being closely related to HERV-K, the ERV does not appear to be within humans and is only found in Asian lorises and absent in all other primates. Due to the staggering similarity of viral insertions of this ERV between the two species of slow lorises, indicates that the current N. coucang genome may actually be a hybrid of the two species or a N. bengalensis from a different population as the reference genome. This study highlights that studying ERVs in more distant primates provides information about the genomes and evolution of these species as well as viral evolution.

genomics↗

bioRxiv2022

A novel micro-ECoG recording method for recording multisensory neural activity from the parietal to temporal cortexes in mice

Characterization of inter-regional interactions in brain is essential for understanding the mechanism relevant to normal brain function and neurological disease. The recently developed flexible micro ()-electrocorticography (ECoG) device is one prominent method used to examine large-scale cortical activity across multiple regions. The sheet-shaped ECoG electrodes arrays can be placed on a relatively wide area of cortical surface beneath the skull by inserting the device into the space between skull and brain. Although rats and mice are useful tools for neuroscience, current ECoG recording methods in these animals are limited to the parietal region of cerebral cortex. Recording cortical activity from the temporal region of cortex in mice has proven difficult because of surgical barriers created by the skull and surrounding temporalis muscle anatomy. Here, we developed a sheet-shaped 64-channel ECoG device that allows access to the mouse temporal cortex, and we determined the factor determining the appropriate bending stiffness for the ECoG electrode array. We also established a surgical technique to implant the electrode arrays into the epidural space over a wide area of cerebral cortex covering from the barrel field to olfactory (piriform) cortex, which is the deepest region of the cerebral cortex. Using histology and computed tomography (CT) images, we confirmed that the tip of the ECoG device reached to the most ventral part of cerebral cortex without causing noticeable damage to the brain surface. Moreover, the device simultaneously recorded somatosensory and odor stimulus-evoked neural activity from dorsal and ventral parts of cerebral cortex in awake and anesthetized mice. These data indicate that our ECoG device and surgical techniques enable the recording of large-scale cortical activity from the parietal to temporal cortex in mice, including somatosensory and olfactory cortices. This system will provide more opportunities for the investigation of physiological functions from wider areas of the mouse cerebral cortex than those currently available with existing ECoG techniques.

neuroscience↗