2,230 research outputs found

    TRIP13 is a protein-remodeling AAA+ ATPase that catalyzes MAD2 conformation switching.

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    The AAA+ family ATPase TRIP13 is a key regulator of meiotic recombination and the spindle assembly checkpoint, acting on signaling proteins of the conserved HORMA domain family. Here we present the structure of the Caenorhabditis elegans TRIP13 ortholog PCH-2, revealing a new family of AAA+ ATPase protein remodelers. PCH-2 possesses a substrate-recognition domain related to those of the protein remodelers NSF and p97, while its overall hexameric architecture and likely structural mechanism bear close similarities to the bacterial protein unfoldase ClpX. We find that TRIP13, aided by the adapter protein p31(comet), converts the HORMA-family spindle checkpoint protein MAD2 from a signaling-active 'closed' conformer to an inactive 'open' conformer. We propose that TRIP13 and p31(comet) collaborate to inactivate the spindle assembly checkpoint through MAD2 conformational conversion and disassembly of mitotic checkpoint complexes. A parallel HORMA protein disassembly activity likely underlies TRIP13's critical regulatory functions in meiotic chromosome structure and recombination

    Dynamic reorganization of the genome shapes the recombination landscape in meiotic prophase.

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    In meiotic prophase, chromosomes are organized into compacted loop arrays to promote homolog pairing and recombination. Here, we probe the architecture of the mouse spermatocyte genome in early and late meiotic prophase using chromosome conformation capture (Hi-C). Our data support the established loop array model of meiotic chromosomes, and infer loops averaging 0.8-1.0 megabase pairs (Mb) in early prophase and extending to 1.5-2.0 Mb in late prophase as chromosomes compact and homologs undergo synapsis. Topologically associating domains (TADs) are lost in meiotic prophase, suggesting that assembly of the meiotic chromosome axis alters the activity of chromosome-associated cohesin complexes. While TADs are lost, physically separated A and B compartments are maintained in meiotic prophase. Moreover, meiotic DNA breaks and interhomolog crossovers preferentially form in the gene-dense A compartment, revealing a role for chromatin organization in meiotic recombination. Finally, direct detection of interhomolog contacts genome-wide reveals the structural basis for homolog alignment and juxtaposition by the synaptonemal complex

    A conserved filamentous assembly underlies the structure of the meiotic chromosome axis.

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    The meiotic chromosome axis plays key roles in meiotic chromosome organization and recombination, yet the underlying protein components of this structure are highly diverged. Here, we show that 'axis core proteins' from budding yeast (Red1), mammals (SYCP2/SYCP3), and plants (ASY3/ASY4) are evolutionarily related and play equivalent roles in chromosome axis assembly. We first identify 'closure motifs' in each complex that recruit meiotic HORMADs, the master regulators of meiotic recombination. We next find that axis core proteins form homotetrameric (Red1) or heterotetrameric (SYCP2:SYCP3 and ASY3:ASY4) coiled-coil assemblies that further oligomerize into micron-length filaments. Thus, the meiotic chromosome axis core in fungi, mammals, and plants shares a common molecular architecture, and likely also plays conserved roles in meiotic chromosome axis assembly and recombination control

    Protocol for the Promoting Resilience in Stress Management (PRISM) Intervention: A Multi-Site Randomized Controlled Trial for Adolescents and Young Adults with Advanced Cancer

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    Background Adolescents and young adults (AYAs) with cancer are at high risk of poor psychosocial outcomes, and evidence-based interventions designed to meet their psychosocial and communication needs are lacking. The main objective of this project is to test the efficacy of a new adaptation of the Promoting Resilience in Stress Management intervention for AYAs with Advanced Cancer (PRISM-AC). Methods/design The PRISM-AC trial is a 2-arm, parallel, non-blinded, multisite, randomized controlled trial. 144 participants with advanced cancer will be enrolled and randomized to either usual, non-directive, supportive care without PRISM-AC (“control” arm) or with PRISM-AC (“experimental” arm). PRISM is a manualized, skills-based training program comprised of four 30–60 min, one-on-one sessions targeting AYA-endorsed resilience resources (stress-management, goal-setting, cognitive-reframing, and meaning-making). It also includes a facilitated family meeting and a fully equipped smartphone app. The current adaptation includes an embedded advance care planning module. English- or Spanish-speaking individuals 12–24 years old with advanced cancer (defined as progressive, recurrent, or refractory disease, or any diagnosis associated with \u3c 50% survival) receiving care at 4 academic medical centers are eligible. Patients’ caregivers are also eligible to participate in this study if they are able to speak and read English or Spanish, and are cognitively and physically able to participate. Participants in all groups complete surveys querying patient-reported outcomes at the time of enrollment and 3-, 6-, 9-, and 12-months post-enrollment. The primary outcome of interest is patient-reported health-related quality of life (HRQOL) and secondary outcomes of interest include patient anxiety, depression, resilience, hope and symptom burden, parent/caregiver anxiety, depression and health-related quality of life, and family palliative care activation. We will conduct intention-to-treat analysis to compare the group means of primary and secondary outcomes between PRISM-AC arm and control arm with regression models. Discussion This study will provide methodologically rigorous data and evidence regarding a novel intervention to promote resilience and reduce distress among AYAs with advanced cancer. This research has the potential to offer a practical, skills-based curriculum designed to improve outcomes for this high-risk group. Trial registration ClinicalTrials.gov Identifier NCT03668223, September 12, 2018

    Gender differences in identities and their socio-structural correlates: how gendered lives shape parental and work identities

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    This study draws on identity theory to explore parental and work identities. It examined gender differences in identities, as well as the moderating role of gender in the effects of individuals’ socio-structural characteristics. A sample of 148 couples with young children completed extensive questionnaires. As hypothesized, couples’ paid work strategy moderated gender differences in the salience and centrality of parental and work identities. Whereas significant differences in identities were found between stay-at-home mothers and their breadwinning husbands, no differences were found among dual-earner couples. Moreover, men’s work identity centrality increased when they had more and younger children, whereas women’s work identity centrality decreased. Finally, men’s parental identity centrality increased with their income, whereas women’s parental identity centrality decreased the more they earned. These findings attest to the importance of examining differences within as well as between genders, by taking into account the interactive effects of gender with other socio-structural characteristics

    Gray space \u3ci\u3eand\u3c/i\u3e green space proximity associated with higher anxiety in youth with autism

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    This study used ZIP code level data on children\u27s health (National Survey of Children\u27s Health, 2012) and land cover (National Land Cover Database, 2011) from across the United States to investigate connections between proximity to green space (tree canopy), gray space (impervious surfaces), and expression of a critical co-morbid condition, anxiety, in three groups of youth: children diagnosed with autism spectrum disorder (ASD, n=1501), non-ASD children with special healthcare needs (CSHCN, n=15,776), and typically developing children (n=53,650). Both impervious surface coverage and tree canopy coverage increased the risk of severe anxiety in youth with autism, but not CSHCN or typical children. Children with ASD might experience the stress-reducing benefits of nature differently than their typically developing peers. More research using objective diagnostic metrics at finer spatial scales would help to illuminate complex relationships between green space, anxiety, and other co-morbid conditions in youth with ASD

    Emission-Line Galaxy Surveys as Probes of the Spatial Distribution of Dwarf Galaxies. I. The University of Michigan Survey

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    Objective-prism surveys which select galaxies on the basis of line-emission are extremely effective at detecting low-luminosity galaxies and constitute some of the deepest available samples of dwarfs. In this study, we confirm that emission-line galaxies (ELGs) in the University of Michigan (UM) objective-prism survey (MacAlpine et al. 1977-1981) are reliable tracers of large-scale structure, and utilize the depth of the samples to examine the spatial distribution of low-luminosity (MB>_{B} > -18.0) dwarfs relative to higher luminosity giant galaxies (MB_{B} \leq -18.0) in the Updated Zwicky Catalogue (Falco et al. 1999). New spectroscopic data are presented for 26 UM survey objects. We analyze the relative clustering properties of the overall starbursting ELG and normal galaxy populations, using nearest neighbor and correlation function statistics. This allows us to determine whether the activity in ELGs is primarily caused by gravitational interactions. We conclude that galaxy-galaxy encounters are not the sole cause of activity in ELGs since ELGs tend to be more isolated and are more often found in the voids when compared to their normal galaxy counterparts. Furthermore, statistical analyses performed on low-luminosity dwarf ELGs show that the dwarfs are less clustered when compared to their non-active giant neighbors. The UM dwarf samples have greater percentages of nearest neighbor separations at large values and lower correlation function amplitudes relative to the UZC giant galaxy samples. These results are consistent with the expectations of galaxy biasing.Comment: 17 pages, 4 tables, 10 figures. Accepted for publication in the Ap

    CD8 T cell effector maturation in HIV-1-infected children

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    AbstractHIV-1 infection generates maturational responses in overall CD4 and CD8 T cell populations in adults, with elevated expression of lytic effector molecules perforin and granzyme B, and reduced expression of CCR7 and CD45RA. Here, we have found that these marked effects were significantly less pronounced in children, both in terms of the skewed CCR7/CD45RA expression profile as well as the increased perforin expression. Similar to adults, HIV-specific CD8 cells in children were largely CD27+ CD45RA− and lacked perforin. However, one pediatric subject with late-stage infection displayed robust expansion of Gag 77–85-specific CD8 T cells which were perforin+ and lytic, but lacked expression of CD27 and IFNγ. Our data indicate that the T cell effector maturation induced by HIV-1 infection is markedly weaker in children as compared to adults. The data also suggest, however, that the perforin-deficient state of HIV-specific CD8 T cells in children may be reversible
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