Genome-Wide Identification of Direct RTA Targets Reveals Key Host Factors for Kaposi's Sarcoma-Associated Herpesvirus Lytic Reactivation.

Kaposi's sarcoma-associated herpesvirus (KSHV) is a human oncogenic virus, which maintains the persistent infection of the host by intermittently reactivating from latently infected cells to produce viral progenies. While it is established that the replication and transcription activator (RTA) viral transcription factor is required for the induction of lytic viral genes for KSHV lytic reactivation, it is still unknown to what extent RTA alters the host transcriptome to promote KSHV lytic cycle and viral pathogenesis. To address this question, we performed a comprehensive time course transcriptome analysis during KSHV reactivation in B-cell lymphoma cells and determined RTA-binding sites on both the viral and host genomes, which resulted in the identification of the core RTA-induced host genes (core RIGs). We found that the majority of RTA-binding sites at core RIGs contained the canonical RBP-Jκ-binding DNA motif. Subsequently, we demonstrated the vital role of the Notch signaling transcription factor RBP-Jκ for RTA-driven rapid host gene induction, which is consistent with RBP-Jκ being essential for KSHV lytic reactivation. Importantly, many of the core RIGs encode plasma membrane proteins and key regulators of signaling pathways and cell death; however, their contribution to the lytic cycle is largely unknown. We show that the cell cycle and chromatin regulator geminin and the plasma membrane protein gamma-glutamyltransferase 6, two of the core RIGs, are required for efficient KSHV reactivation and virus production. Our results indicate that host genes that RTA rapidly and directly induces can be pivotal for driving the KSHV lytic cycle.IMPORTANCE The lytic cycle of KSHV is involved not only in the dissemination of the virus but also viral oncogenesis, in which the effect of RTA on the host transcriptome is still unclear. Using genomics approaches, we identified a core set of host genes which are rapidly and directly induced by RTA in the early phase of KSHV lytic reactivation. We found that RTA does not need viral cofactors but requires its host cofactor RBP-Jκ for inducing many of its core RIGs. Importantly, we show a critical role for two of the core RIGs in efficient lytic reactivation and replication, highlighting their significance in the KSHV lytic cycle. We propose that the unbiased identification of RTA-induced host genes can uncover potential therapeutic targets for inhibiting KSHV replication and viral pathogenesis.

Dental students' perspectives on three intraoral scanners and CAD/CAM systems before and after a pre-clinical elective course in digital dentistry.

Background: Intraoral scanners (IOS) are gaining interest in Dentistry for their ability to capture digital impressions of the oral cavity. These digital impressions facilitate the fabrication of indirect restorations using CAD/CAM technology. This study aimed to describe an elective course given to predoctoral dental students on the topic of Digital Dentistry and assess their learning outcomes and system preferences. Material and Methods: Three IOS were evaluated by eight students enrolled in a Digital Dentistry elective course. These systems included Emerald S (Planmeca), Cerec Omnicam (Denstply Sirona), and True Definition (3M/Midmark). After a literature review and a hands-on session were completed for each system, the students provided their perspectives on various factors such as ease of use, organization, and user-friendliness in a qualitative narrative of each system and quantitatively through a six-items survey. Results: Survey data suggests that the student cohort showed higher levels of previous familiarity, user preference, and clinical confidence in the Cerec and Planmeca systems as opposed to the True Definition system. Qualitatively, the students felt CEREC was the more educationally useful system to learn and presented with more ease of use, functionality, and efficacy than the other two systems. Conclusions: While each system proved to have its unique benefits and drawbacks, students' attitudes towards the Planmeca and Cerec systems were generally positive, while True Definition's evaluation was limited. Students appreciated their experiences throughout this elective, familiarizing themselves with various digital systems. Key words:Digital Dentistry, Intraoral Scanners, CAD/CAM, Dental Education, Learning Curve.