Expansion of a VR Exposure Therapy System for Combat-Related PTSD to Medics/Corpsman and Persons Following Military Sexual Trauma.

The stressful experiences that have been characteristic of the combat environments in Iraq and Afghanistan have produced significant numbers of returning service members at risk for developing posttraumatic stress disorder and other psychosocial/behavioral health conditions. This paper describes a set of projects that are expanding the content for inclusion in a newly updated "Virtual Iraq/Afghanistan" Virtual Reality system for the delivery of exposure therapy (VRET) for PTSD with Service Members and Veterans. In addition to the complete rebuilding of this VRET system using the latest version of the Unity Game Engine, the system's content and functionality has been expanded to now support the use of VRET with combat medics/corpsmen and persons who have experienced military sexual trauma (MST). The focus of this paper is to present the rationale and general overview of the progress on these projects that will provide new relevant and customizable options for conducting VRET with a wider range of trauma experiences.

User-state sensing for virtual health agents and telehealth applications.

Nonverbal behaviors play a crucial role in shaping outcomes in face-to-face clinical interactions. Experienced clinicians use nonverbals to foster rapport and "read" their clients to inform diagnoses. The rise of telemedicine and virtual health agents creates new opportunities, but it also strips away much of this nonverbal channel. Recent advances in low-cost computer vision and sensing technologies have the potential to address this challenge by learning to recognize nonverbal cues from large datasets of clinical interactions. These techniques can enhance both telemedicine and the emerging technology of virtual health agents. This article describes our current research in addressing these challenges in the domain of PTSD and depression screening for U.S. Veterans. We describe our general approach and report on our initial contribution: the creation of a large dataset of clinical interview data that facilitates the training of user-state sensing technology.

Functional association of Gdown1 with RNA polymerase II poised on human genes.

Most human genes are loaded with promoter-proximally paused RNA polymerase II (Pol II) molecules that are poised for release into productive elongation by P-TEFb. We present evidence that Gdown1, the product of the POLR2M gene that renders Pol II responsive to Mediator, is involved in Pol II elongation control. During in vitro transcription, Gdown1 specifically blocked elongation stimulation by TFIIF, inhibited the termination activity of TTF2, and influenced pausing factors NELF and DSIF, but did not affect the function of TFIIS or the mRNA capping enzyme. Without P-TEFb, Gdown1 led to the production of stably paused polymerases in the presence of nuclear extract. Supporting these mechanistic insights, ChIP-Seq demonstrated that Gdown1 mapped over essentially all poised polymerases across the human genome. Our results establish that Gdown1 stabilizes poised polymerases while maintaining their responsiveness to P-TEFb and suggest that Mediator overcomes a Gdown1-mediated block of initiation by allowing TFIIF function.

Functional coupling of cleavage and polyadenylation with transcription of mRNA.

Cleavage and polyadenylation define the 3' ends of almost all eukaryotic mRNAs and are thought to occur during transcription. We describe a human in vitro system utilizing an immobilized template, in which transcripts in RNA polymerase II elongation complexes are efficiently cleaved and polyadenylated. Because the cleavage rate of free RNA is much slower, we conclude that cleavage is functionally coupled to transcription. Inhibition of positive transcription elongation factor b (P-TEFb) had only a modest negative effect on cleavage, as long as transcripts were long enough to contain the polyadenylation signal. In contrast, removal of the carboxyl-terminal domain of the large subunit of RNA polymerase II had a dramatic negative effect on cleavage. Unexpectedly, the 5' portion of transcript after cleavage remained associated with the template in a functional, polyadenylation-competent complex. Efficient cleavage required 5' capping by the human capping enzyme, but the reduction of cleavage seen of transcripts in COOH-terminal domain-less polymerase elongation complexes, was not because of lack of capping.

Binding of the 7SK snRNA turns the HEXIM1 protein into a P-TEFb (CDK9/cyclin T) inhibitor.

The positive transcription elongation factor b (P-TEFb) plays a pivotal role in productive elongation of nascent RNA molecules by RNA polymerase II. Core active P-TEFb is composed of CDK9 and cyclin T. In addition, mammalian cell extracts contain an inactive P-TEFb complex composed of four components, CDK9, cyclin T, the 7SK snRNA and the MAQ1/HEXIM1 protein. We now report an in vitro reconstitution of 7SK-dependent HEXIM1 association to purified P-TEFb and subsequent CDK9 inhibition. Yeast three-hybrid tests and gel-shift assays indicated that HEXIM1 binds 7SK snRNA directly and a 7SK snRNA-recognition motif was identified in the central part of HEXIM1 (amino acids (aa) 152-155). Data from yeast two-hybrid and pull-down assay on GST fusion proteins converge to a direct binding of P-TEFb to the HEXIM1 C-terminal domain (aa 181-359). Consistently, point mutations in an evolutionarily conserved motif (aa 202-205) were found to suppress P-TEFb binding and inhibition without affecting 7SK recognition. We propose that the RNA-binding domain of HEXIM1 mediates its association with 7SK and that P-TEFb then enters the complex through association with HEXIM1.

Cotranscriptional processing of Drosophila histone mRNAs.

The 3' ends of metazoan histone mRNAs are generated by specialized processing machinery that cleaves downstream of a conserved stem-loop structure. To examine how this reaction might be influenced by transcription, we used a Drosophila melanogaster in vitro system that supports both processes. In this system the complete synthesis of histone mRNA, including transcription initiation and elongation, followed by 3' end formation, occurred at a physiologically significant rate. Processing of free transcripts was efficient and occurred with a t(1/2) of less than 1 min. Divalent cations were not required, but nucleoside triphosphates (NTPs) stimulated the rate of cleavage slightly. Isolated elongation complexes encountered a strong arrest site downstream of the mature histone H4 3' end. In the presence of NTPs, transcripts in these arrested complexes were processed at a rate similar to that of free RNA. Removal of NTPs dramatically reduced this rate, potentially due to concealment of the U7 snRNP binding element. The arrest site was found to be a conserved feature located 32 to 35 nucleotides downstream of the processing site on the H4, H2b, and H3 genes. The significance of the newly discovered arrest sites to our understanding of the coupling between transcription and RNA processing on the one hand and histone gene expression on the other is discussed.