Bringing Gratitude to Aphasia Intervention: A Scoping Review of Gratitude Interventions for Adults with Chronic Health Conditions.

Aphasia negatively impacts mental health, disrupting social connections and meaningful life activities. Gratitude interventions for healthy adults positively impact well-being, physical health, and mental health. A systematic review of gratitude interventions for people living with chronic health conditions was conducted to identify current practices and existing gaps and to map the literature for incorporating gratitude interventions into aphasia rehabilitation. A scoping review of the literature published prior to March 2023 was conducted using CINAHL, Google Scholar, PubMed, and ERIC to identify gratitude interventions for adults with chronic health conditions. The search identified 414 studies. Five met the inclusion criteria. Interventions targeting chronic health conditions included alcohol use disorder, chronic heart failure, cancer, and asthma. No empirical studies were identified that used gratitude interventions with people who have aphasia or have had a stroke. Four studies used journaling as the intervention and one used gratitude letters. All interventions used written or verbal expressions of gratitude. Gratitude interventions have been used in limited ways with chronic health conditions. As gratitude interventions are language-based and rely on writing, people with aphasia may need modifications to support accessibility to these interventions which can positively impact mental health and well-being.

Mechanistic Insight into NMDA Receptor Dysregulation by Rare Variants in the GluN2A and GluN2B Agonist Binding Domains.

Epilepsy and intellectual disability are associated with rare variants in the GluN2A and GluN2B (encoded by GRIN2A and GRIN2B) subunits of the N-methyl-D-aspartate receptor (NMDAR), a ligand-gated ion channel with essential roles in brain development and function. By assessing genetic variation across GluN2 domains, we determined that the agonist binding domain, transmembrane domain, and the linker regions between these domains were particularly intolerant to functional variation. Notably, the agonist binding domain of GluN2B exhibited significantly more variation intolerance than that of GluN2A. To understand the ramifications of missense variation in the agonist binding domain, we investigated the mechanisms by which 25 rare variants in the GluN2A and GluN2B agonist binding domains dysregulated NMDAR activity. When introduced into recombinant human NMDARs, these rare variants identified in individuals with neurologic disease had complex, and sometimes opposing, consequences on agonist binding, channel gating, receptor biogenesis, and forward trafficking. Our approach combined quantitative assessments of these effects to estimate the overall impact on synaptic and non-synaptic NMDAR function. Interestingly, similar neurologic diseases were associated with both gain- and loss-of-function variants in the same gene. Most rare variants in GluN2A were associated with epilepsy, whereas GluN2B variants were associated with intellectual disability with or without seizures. Finally, discerning the mechanisms underlying NMDAR dysregulation by these rare variants allowed investigations of pharmacologic strategies to correct NMDAR function.

The Bioactive Protein-Ligand Conformation of GluN2C-Selective Positive Allosteric Modulators Bound to the NMDA Receptor.

N-methyl-d-aspartate (NMDA) receptors are ligand-gated, cation-selective channels that mediate a slow component of excitatory synaptic transmission. Subunit-selective positive allosteric modulators of NMDA receptor function have therapeutically relevant effects on multiple processes in the brain. A series of pyrrolidinones, such as PYD-106, that selectively potentiate NMDA receptors that contain the GluN2C subunit have structural determinants of activity that reside between the GluN2C amino terminal domain and the GluN2C agonist binding domain, suggesting a unique site of action. Here we use molecular biology and homology modeling to identify residues that line a candidate binding pocket for GluN2C-selective pyrrolidinones. We also show that occupancy of only one site in diheteromeric receptors is required for potentiation. Both GluN2A and GluN2B can dominate the sensitivity of triheteromeric receptors to eliminate the actions of pyrrolidinones, thus rendering this series uniquely sensitive to subunit stoichiometry. We experimentally identified NMR-derived conformers in solution, which combined with molecular modeling allows the prediction of the bioactive binding pose for this series of GluN2C-selective positive allosteric modulators of NMDA receptors. These data advance our understanding of the site and nature of the ligand-protein interaction for GluN2C-selective positive allosteric modulators for NMDA receptors.

GluN2D-Containing N-methyl-d-Aspartate Receptors Mediate Synaptic Transmission in Hippocampal Interneurons and Regulate Interneuron Activity.

N-methyl-d-aspartate receptors (NMDARs) are ionotropic glutamatergic receptors that have been implicated in learning, development, and neuropathological conditions. They are typically composed of GluN1 and GluN2A-D subunits. Whereas a great deal is known about the role of GluN2A- and GluN2B-containing NMDARs, much less is known about GluN2D-containing NMDARs. Here we explore the subunit composition of synaptic NMDARs on hippocampal interneurons. GluN2D mRNA was detected by single-cell PCR and in situ hybridization in diverse interneuron subtypes in the CA1 region of the hippocampus. The GluN2D subunit was detectable by immunoblotting and immunohistochemistry in all subfields of the hippocampus in young and adult mice. In whole-cell patch-clamp recordings from acute hippocampal slices, (+)-CIQ, the active enantiomer of the positive allosteric modulator CIQ, significantly enhanced the amplitude of the NMDAR component of miniature excitatory postsynaptic currents (mEPSCs) in CA1 interneurons but not in pyramidal cells. (+)-CIQ had no effect in slices from Grin2d-/- mice, suggesting that GluN2D-containing NMDARs participate in excitatory synaptic transmission onto hippocampal interneurons. The time course of the NMDAR component of the mEPSC was unaffected by (+)-CIQ potentiation and was not accelerated in slices from Grin2d-/- mice compared with wild-type, suggesting that GluN2D does not detectably slow the NMDAR EPSC time course at this age. (+)-CIQ increased the activity of CA1 interneurons as detected by the rate and net charge transfer of spontaneous inhibitory postsynaptic currents (sIPSCs) recorded from CA1 pyramidal cells. These data provide evidence that interneurons contain synaptic NMDARs possessing a GluN2D subunit, which can influence interneuron function and signal processing.

Supporting Participation Through Project-Based Intervention: A Tutorial for Working With People With Aphasia in Individual Sessions.

PURPOSE: Participation is an integral focus of services to people with aphasia and is considered best practice within the scope of practice for speech-language pathology. The Life Participation Approach to Aphasia encourages meaningful participation in life for people living with aphasia. In theory, providing participation-based services to people with aphasia seems logical; however, embedding these constructs of participation into practice can be challenging for speech-language pathologists (SLPs). Project-based intervention (PBI) provides an authentic opportunity to target participation and support identity reformulation in aphasia intervention. Historically, projects have been provided primarily in group-based settings, which may be difficult for the majority of SLPs who primarily offer individual sessions due to reimbursement. This tutorial provides a framework for using PBI in individual sessions for clients with aphasia using five evidence-based components: (a) shared decision making, (b) patient-reported outcomes, (c) goal setting, (d) the project, and (e) ongoing evaluation. Evidence-based tools and a case example are provided to support each component. CONCLUSIONS: Projects and PBI provide tangible means of placing participation at the center of intervention while also providing opportunities to target language impairments, identity reconstruction, and various environments in a meaningful and personalized way. Projects can be scaled to the client's needs and abilities as well as to the constraints and options of the service delivery setting.

"I Could Not Talk . . . She Did Everything . . . She's Now My Sister": People With Aphasia's Perspectives on Friends Who Stuck Around.

PURPOSE: Aphasia may decrease the capacity to develop and maintain friendships. The aim of this study was to better understand the perspectives of people with aphasia on why some friendship bonds remain strong and some do not. Furthermore, we wanted to explore how age and aphasia severity shape views on friendship. METHOD: We interviewed 27 people with aphasia about their experiences of friendship before and after the onset of aphasia. We then used framework analysis and reflexive thematic analysis to interpret the interview data. RESULTS: From the interviews, we created four major themes concerning how friend relationships had been impacted by aphasia: (a) Not all bonds have the same chance of surviving the onset of aphasia; (b) people with aphasia's closest friends took active steps to keep relationships strong; (c) if friends knew some basic information about aphasia, bonds would stay stronger; (d) positive affective aspects of friendship play an important role in keeping bonds strong. We also noted differences in friendship experiences that appeared to be influenced by age and aphasia severity of participants. CONCLUSIONS: Interview data provided actionable ideas including focusing on friends who are likely to be responsive to help with maintaining the friendship, providing them with strategies to keep the friendship active and communication meaningful, and acknowledging the positive impact that this will have on the friend recovering from aphasia. More research is needed to develop programs that empower people with aphasia to maintain their friendships. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.24688671.

"It's not often that people want to hear me talk about my life": Storytelling experiences of people with aphasia in an interdisciplinary songwriting project.

PURPOSE: Storytelling is an integral part of human life, providing opportunities for social closeness, relationship development, and identity exploration. Having aphasia can disrupt the ability to convey stories across a variety of settings. Structured songwriting frameworks may provide people with aphasia an opportunity to successfully engage in this medium for storytelling. METHOD: Three individuals with aphasia participated in a structured songwriting intervention modified to support individuals with aphasia. Each participant-songwriter co-constructed three songs about their life in collaboration with an interdisciplinary team. Data about the songwriting process were collected via individual semi-structured qualitative interview and analysed using interpretative phenomenological analysis to identify superordinate themes and subthemes. RESULT: The overarching superordinate theme related to the process itself as a catalyst that occurred as a result of participating in a songwriting intervention modified for individuals with aphasia. Three subthemes were identified: (a) relationship-centred experience, (b) engagement in meaningful activities, and (c) identity exploration. CONCLUSION: Songwriting may provide meaningful opportunities for people with aphasia to experience the power of sharing stories about themselves. Key components of this experience aligned with the core elements of the positive psychology PERMA (Positive Emotion, Engagement, Relationships, Meaning, and Accomplishments) framework. Findings support incorporating storytelling through songwriting into the rehabilitation journey for individuals with aphasia.

A scoping review of friendship intervention for older adults: lessons for designing intervention for people with aphasia.

PURPOSE: Map the landscape of friendship interventions/programs for older adults to guide intervention/program development inclusive of the unique needs of older people with aphasia (PWA). METHODS: A search query of multiple databases was completed for articles published before 4 January 2021. Studies included all the following: (1) participants aged 55 years or older; (2) addressed an intervention/program designed to prevent social isolation and/or friendship loss; (3) used an outcome variable related to social isolation and/or friendship; and (4) published in a peer-reviewed journal. Title and abstract screening were conducted using Covidence software, which tracked disagreements across the study team. All studies included in the full-text review were identified as relevant by a minimum of two study authors, and a consensus was reached on all full-text reviews. Data were extracted according to (1) theoretical frameworks used; (2) interventionist and discipline; (3) participant characteristics; (4) intervention/program replicability; (5) format of intervention/program; (6) measures used in the intervention/programs; (7) and, reported effects of intervention/programs on individuals. RESULTS: A total of 40 articles with 42 intervention/programs were included and represented 4584 intervention/program participants ranging in age from 40 to 104 years. Intervention/programs involved a wide range of theoretical frameworks (e.g., theories of loneliness, feminist theory, positive psychology). Disciplines such as psychology and exercise science informed intervention/programs. Interventionists included many types of individuals like therapists, volunteers and home health aides. Intervention/programs often lacked adequate description for replication and included individual and group formats, most commonly delievered in the participants homes. Outcomes usually included self-report measures of loneliness, social networks, or well-being, and intervention/programming was primarily educational, activity-based, or networking-based in nature. CONCLUSIONS: The intervention/programs reviewed yield important lessons to support innovation in developing friendship intervention/programs for older PWA as most yielded positive results and were acceptable to participants.IMPLICATIONS FOR REHABILITATIONPeople with aphasia want their friendships addressed as part of their rehabilitation; however, the research literature has little guidance in this area.Studies reviewed of friendship intervention/programs for older adults yielded helpful lessons for consideration in developing this type of intervention/programming for people with aphasia.Interprofessional teams made up of rehabilitation professionals should address friendship for people with aphasia in both research and clinical practice.

How Do You Do Talk Therapy With Someone Who Can't Talk? Perspectives From Mental Health Providers on Delivering Services to Individuals With Aphasia.

Purpose Aphasia is correlated with depression and anxiety, and it has a negative impact on quality of life. Aphasia is also frequently misunderstood among mental health care providers. The aim of this study was to explore the experiences of mental health providers who provide services to people living with aphasia. Method Interpretative phenomenological analysis was used to analyze interviews of six mental health providers who had some experience in providing services to people with aphasia. Results Three main themes among mental health care providers' experiences providing services to people with aphasia were identified: barriers, interprofessional collaboration, and therapy looks different. Subthemes associated with barriers included insufficient training and knowledge of aphasia, the stigma of receiving mental health services, and accessibility to services. Subthemes related to interdisciplinary collaboration included referrals, knowledge and awareness, and strategies and tools. Subthemes supporting therapy looks different included a new approach to therapy and challenges. Conclusions Mental health providers' experiences reveal the need for an action-oriented approach to overcome barriers, a nontraditional approach to talk therapy for people with aphasia, and increased collaboration with speech-language pathologists (SLPs). Future research should explore expanding the collaboration between SLPs and mental health providers to increase shared knowledge and skills in issues related to reducing depression and anxiety to support the well-being of people with aphasia.

Recurrent seizure-related GRIN1 variant: Molecular mechanism and targeted therapy.

OBJECTIVE: Genetic variants in the GRIN genes that encode N-methyl-D-aspartate receptor (NMDAR) subunits have been identified in various neurodevelopmental disorders, including epilepsy. We identified a GRIN1 variant from an individual with early-onset epileptic encephalopathy, evaluated functional changes to NMDAR properties caused by the variant, and screened FDA-approved therapeutic compounds as potential treatments for the patient. METHODS: Whole exome sequencing identified a missense variant in GRIN1. Electrophysiological recordings were made from Xenopus oocytes and transfected HEK cells to determine the NMDAR biophysical properties as well as the sensitivity to agonists and FDA-approved drugs that inhibit NMDARs. A beta-lactamase reporter assay in transfected HEK cells evaluated the effects of the variant on the NMDAR surface expression. RESULTS: A recurrent de novo missense variant in GRIN1 (c.1923G>A, p.Met641Ile), which encodes the GluN1 subunit, was identified in a pediatric patient with drug-resistant seizures and early-onset epileptic encephalopathy. In vitro analysis indicates that GluN1-M641I containing NMDARs showed enhanced agonist potency and reduced Mg2+ block, which may be associated with the patient's phenotype. Results from screening FDA-approved drugs suggested that GluN1-M641I containing NMDARs are more sensitive to the NMDAR channel blockers memantine, ketamine, and dextromethorphan compared to the wild-type receptors. The addition of memantine to the seizure treatment regimen significantly reduced the patient's seizure burden. INTERPRETATION: Our finding contributes to the understanding of the phenotype-genotype correlations of patients with GRIN1 gene variants, provides a molecular mechanism underlying the actions of this variant, and explores therapeutic strategies for treating GRIN1-related neurological conditions.

Distinct GluN1 and GluN2 Structural Determinants for Subunit-Selective Positive Allosteric Modulation of N-Methyl-d-aspartate Receptors.

N-Methyl-d-aspartate receptors (NMDARs) are ionotropic ligand-gated glutamate receptors that mediate fast excitatory synaptic transmission in the central nervous system (CNS). Several neurological disorders may involve NMDAR hypofunction, which has driven therapeutic interest in positive allosteric modulators (PAMs) of NMDAR function. Here we describe modest changes to the tetrahydroisoquinoline scaffold of GluN2C/GluN2D-selective PAMs that expands activity to include GluN2A- and GluN2B-containing recombinant and synaptic NMDARs. These new analogues are distinct from GluN2C/GluN2D-selective compounds like (+)-(3-chlorophenyl)(6,7-dimethoxy-1-((4-methoxyphenoxy)methyl)-3,4-dihydroisoquinolin-2(1H)-yl)methanone (CIQ) by virtue of their subunit selectivity, molecular determinants of action, and allosteric regulation of agonist potency. The (S)-enantiomers of two analogues (EU1180-55, EU1180-154) showed activity at NMDARs containing all subunits (GluN2A, GluN2B, GluN2C, GluN2D), whereas the (R)-enantiomers were primarily active at GluN2C- and GluN2D-containing NMDARs. Determination of the actions of enantiomers on triheteromeric receptors confirms their unique pharmacology, with greater activity of (S) enantiomers at GluN2A/GluN2D and GluN2B/GluN2D subunit combinations than (R) enantiomers. Evaluation of the (S)-EU1180-55 and EU1180-154 response of chimeric kainate/NMDA receptors revealed structural determinants of action within the pore-forming region and associated linkers. Scanning mutagenesis identified structural determinants within the GluN1 pre-M1 and M1 regions that alter the activity of (S)-EU1180-55 but not (R)-EU1180-55. By contrast, mutations in pre-M1 and M1 regions of GluN2D perturb the actions of only the (R)-EU1180-55 but not the (S) enantiomer. Molecular modeling supports the idea that the (S) and (R) enantiomers interact distinctly with GluN1 and GluN2 pre-M1 regions, suggesting that two distinct sites exist for these NMDAR PAMs, each of which has different functional effects.

Discovery of Dihydropyrrolo[1,2-a]pyrazin-3(4H)-one-Based Second-Generation GluN2C- and GluN2D-Selective Positive Allosteric Modulators (PAMs) of the N-Methyl-d-Aspartate (NMDA) Receptor.

The N-methyl-d-aspartate receptor (NMDAR) is an ion channel that mediates the slow, Ca2+-permeable component of glutamatergic synaptic transmission in the central nervous system (CNS). NMDARs are known to play a significant role in basic neurological functions, and their dysfunction has been implicated in several CNS disorders. Herein, we report the discovery of second-generation GluN2C/D-selective NMDAR-positive allosteric modulators (PAMs) with a dihydropyrrolo[1,2-a]pyrazin-3(4H)-one core. The prototype, R-(+)-EU-1180-453, exhibits log unit improvements in the concentration needed to double receptor response, lipophilic efficiency, and aqueous solubility, and lowers cLogP by one log unit compared to the first-generation prototype CIQ. Additionally, R-(+)-EU-1180-453 was found to increase glutamate potency 2-fold, increase the response to maximally effective concentration of agonist 4-fold, and the racemate is brain-penetrant. These compounds are useful second-generation in vitro tools and a promising step toward in vivo tools for the study of positive modulation of GluN2C- and GluN2D-containing NMDA receptors.

More Than a Story: My Life Came Back to Life.

Purpose: Social models of aphasia rehabilitation emphasize the importance of supporting identity renegotiation, which can be accomplished in part through personal narrative construction. The purpose of this study was to examine the experiences of persons who had engaged in a project to coconstruct personal narratives about life with aphasia. Method: Qualitative interviews were conducted with 3 participants with aphasia who completed a 4-week personal narrative coconstruction project, which included preadministration and postadministration of the Communication Confidence Rating Scale for Aphasia (Cherney & Babbitt, 2011). Results were analyzed using interpretative phenomenological analysis. Results: Three themes were revealed: (a) More than a story: It changed my life validated the idea that the narrative coconstruction process supported a positive view of identity; (b) A positive experience captured the participants' enjoyment in coconstructing and sharing their story; (c) Hope engendered by the coconstruction experience empowered participants with new levels of confidence not only in their communication skills but also in themselves. Conclusions: This study provided insight into the experience of coconstructing personal narratives using a structured protocol. Participants experienced the project as a positive, meaningful opportunity to actively contemplate their life and look forward. The study has implications for clinicians considering support of identity renegotiation in aphasia rehabilitation.

The Structure-Activity Relationship of a Tetrahydroisoquinoline Class of N-Methyl-d-Aspartate Receptor Modulators that Potentiates GluN2B-Containing N-Methyl-d-Aspartate Receptors.

We have identified a series of positive allosteric NMDA receptor (NMDAR) modulators derived from a known class of GluN2C/D-selective tetrahydroisoquinoline analogues that includes CIQ. The prototypical compound of this series contains a single isopropoxy moiety in place of the two methoxy substituents present in CIQ. Modifications of this isopropoxy-containing scaffold led to the identification of analogues with enhanced activity at the GluN2B subunit. We identified molecules that potentiate the response of GluN2B/GluN2C/GluN2D, GluN2B/GluN2C, and GluN2C/GluN2D-containing NMDARs to maximally effective concentrations of agonist. Multiple compounds potentiate the response of NMDARs with submicromolar EC50 values. Analysis of enantiomeric pairs revealed that the S-(-) enantiomer is active at the GluN2B, GluN2C, and/or GluN2D subunits, whereas the R-(+) enantiomer is only active at GluN2C/D subunits. These results provide a starting point for the development of selective positive allosteric modulators for GluN2B-containing receptors.

NMDA receptor modulators: an updated patent review (2013-2014).

INTRODUCTION: The NMDA receptor mediates a slow component of excitatory synaptic transmission, and NMDA receptor dysfunction has been implicated in numerous neurological disorders. Thus, interest in developing modulators that are capable of regulating the channel continues to be strong. Recent research has led to the discovery of a number of compounds that hold therapeutic and clinical value. Deeper insight into the NMDA intersubunit interactions and structural motifs gleaned from the recently solved crystal structures of the NMDA receptor should facilitate a deeper understanding of how these compounds modulate the receptor. AREAS COVERED: This article discusses the known pharmacology of NMDA receptors. A discussion of the patent literature since 2012 is also included, with an emphasis on those that claimed new chemical entities as regulators of the NMDA receptor. EXPERT OPINION: The number of patents involving novel NMDA receptor modulators suggests a renewed interest in the NMDA receptor as a therapeutic target. Subunit-selective modulators continue to show promise, and the development of new subunit-selective NMDA receptor modulators appears poised for continued growth. Although a modest number of channel blocker patents were published, successful clinical outcomes involving ketamine have led to a resurgent interest in low-affinity channel blockers as therapeutics.

Synthesis and structure activity relationship of tetrahydroisoquinoline-based potentiators of GluN2C and GluN2D containing N-methyl-D-aspartate receptors.

We describe here the synthesis and evaluation of a series of tetrahydroisoquinolines that show subunit-selective potentiation of NMDA receptors containing the GluN2C or GluN2D subunits. Bischler-Napieralski conditions were employed in the key step for the conversion of acyclic amides to the corresponding tetrahydroisoquinoline-containing analogs. Compounds were evaluated using both two-electrode voltage clamp recordings from Xenopus laevis oocytes and imaging of mammalian BHK cells loaded with Ca(2+)-sensitive dyes. The most potent analogues had EC50 values of 300 nM and showed over 2-fold potentiation of the response to maximally effective concentrations of glutamate and glycine but had no effect on responses from NMDA receptors containing the GluN2A or GluN2B subunits AMPA, kainate, and GABA or glycine receptors or a variety of other potential targets. These compounds represent a potent class of small molecule subunit-selective potentiators of NMDA receptors.

Novel NMDA receptor modulators: an update.

INTRODUCTION: The NMDA receptor is a ligand-gated ion channel that plays a critical role in higher level brain processes and has been implicated in a range of neurological and psychiatric conditions. Although initial studies for the use of NMDA receptor antagonists in neuroprotection were unsuccessful, more recently, NMDA receptor antagonists have shown clinical promise in other indications such as Alzheimer's disease, Parkinson's disease, pain and depression. Based on the clinical observations and more recent insights into receptor pharmacology, new modulatory approaches are beginning to emerge, with potential therapeutic benefit. AREAS COVERED: The article covers the known pharmacology and important features regarding NMDA receptors and their function. A discussion of pre-clinical and clinical relevance is included, as well. The subsequent patent literature review highlights the current state of the art targeting the receptor since the last review in 2010. EXPERT OPINION: The complex nature of the NMDA receptor structure and function is becoming better understood. As knowledge about this receptor increases, it opens up new opportunities for targeting the receptor for many therapeutic indications. New strategies and advances in older technologies will need to be further developed before clinical success can be achieved. First-in-class potentiators and subunit-selective agents form the basis for most new strategies, complemented by efforts to limit off-target liability and fine-tune on-target properties.

Crystallization of the Oct-1/SNAP190 peptide/DNA complex.

Crystals of the Oct-1 POU/SNAP190 peptide/DNA tertiary complex have been obtained by hanging-drop vapor diffusion at 293K in 20% 2-propanol, 20% PEG 4000 and 0.1M sodium citrate pH 5.6. The Oct-1 POU protein has two domains, one a homeodomain and the other a POU domain, which are connected by a flexible linker. The DNA used in the complex is slightly different in the octamer region compared with the two previously crystallized Oct-1 POU/DNA complexes. The DNA is 14 base pairs, with an octamer sequence of 5'-ATGTAGAT-3' and an overhang of one base on both strands. The SNAP190 peptide is 27 amino acids long (residues 884-910). The crystals diffract to 2.3 A (94.1% completeness) at the synchrotron under cryogenic (123K) conditions. The crystals are triclinic, space group P1, with unit-cell parameters a = 36.4, b = 54.9, c = 77.6A, alpha = 94.9, beta = 99.6, gamma = 109.2 degrees. This structure will provide insight into how Oct-1 interacts with SNAP190, a critical component of the small nuclear RNA-activating protein complex (SNAPc). Transcription of human snRNA genes is activated by these direct protein-protein interactions.

Activator recruitment by the general transcription machinery: X-ray structural analysis of the Oct-1 POU domain/human U1 octamer/SNAP190 peptide ternary complex.

Transcriptional activation of the human U1 snRNA genes is dependent on a noncanonical octamer element contained within an upstream enhancer. The U1 octamer only weakly recruits the Oct-1 POU domain, although recruitment is stimulated by a peptide containing the Oct-1-binding domain of SNAP190. Structural analysis of the Oct-1 POU domain/U1 octamer/SNAP190 peptide complex revealed that SNAP190 makes extensive protein contacts with the Oct-1 POU-specific domain and with the DNA phosphate backbone within the enhancer. Although SNAP190 and OCA-B both interact with the Oct-1 POU domain through the same Oct-1 interface, a single nucleotide within the U1 octamer ablates OCA-B recruitment without compromising activator recruitment by SNAP190.