A unique role for the Rb protein in controlling E2F accumulation during cell growth and differentiation.

Examination of the interactions involving transcription factor E2F activity during cell growth and terminal differentiation suggests distinct roles for Rb family members in the regulation of E2F accumulation. The major species of E2F in quiescent cells is a complex containing the E2F4 product in association with the Rb-related p130 protein. As cells enter the cell cycle, this complex disappears, and there is a concomitant accumulation of free E2F activity of which E2F4 is a major component. E2F4 then associates with the Rb-related p107 protein as cells enter S phase. Rb can be found in interactions with each E2F species, including E2F4, during G1, but there appears to be a limited amount of Rb with respect to E2F, likely due to the maintenance of most Rb protein in an inactive state by phosphorylation. A contrasting circumstance can be found during the induction of HL60 cell differentiation. As these cells exit the cell cycle, active Rb protein appears to exceed E2F, as there is a marked accumulation of E2F-Rb interactions, involving all E2F species, including E2F4, which is paralleled by the conversion of Rb from a hyperphosphorylated state to a hypophosphorylated state. These results suggest that the specific ability of Rb protein to interact with each E2F species, dependent on concentration of active Rb relative to accumulation of E2F, may be critical in cell-growth decisions.

Cell-cell communication regulates the effects of protein aspartate phosphatases on the phosphorelay controlling development in Bacillus subtilis.

Rap phosphatases are a recently discovered family of protein aspartate phosphatases that dephosphorylate the Spo0F--P intermediate of the phosphorelay, thus preventing sporulation of Bacillus subtilis. They are regulators induced by physiological processes that are antithetical to sporulation. The RapA phosphatase is induced by the ComP-ComA two-component signal transduction system responsible for initiating competence. RapA phosphatase activity was found to be controlled by a small protein, PhrA, encoded on the same transcript as RapA. PhrA resembles secreted proteins and the evidence suggests that it is cleaved by signal peptidase I and a 19-residue C-terminal domain is secreted from the cell. The sporulation deficiency caused by the uncontrolled RapA activity of a phrA mutant can be complemented by synthetic peptides comprising the last six or more of the C-terminal residues of PhrA. Whether the peptide controls RapA activity directly or by regulating its synthesis remains to be determined. Complementation of the phrA mutant can also be obtained in mixed cultures with a wild-type strain, suggesting the peptide may serve as a means of communication between cells. Importation of the secreted peptide required the oligopeptide transport system. The sporulation deficiency of oligopeptide transport mutants can be suppressed by mutating the rapA and rapB genes or by introduction of a spo0F mutation Y13S that renders the protein insensitive to Rap phosphatases. The data indicate that the sporulation deficiency of oligopeptide transport mutants is due to their inability to import the peptides controlling Rap phosphatases.

UME6 is a central component of a developmental regulatory switch controlling meiosis-specific gene expression.

The UME6 gene of Saccharomyces cerevisiae was identified as a mitotic repressor of early meiosis-specific gene expression. It encodes a Zn2Cys6 DNA-binding protein which binds to URS1, a promoter element needed for both mitotic repression and meiotic induction of early meiotic genes. This paper demonstrates that a complete deletion of UME6 causes not only vegetative derepression of early meiotic genes during vegetative growth but also a significant reduction in induction of meiosis-specific genes, accompanied by a severe defect in meiotic progression. After initiating premeiotic DNA synthesis the vast majority of cells (approximately 85%) become arrested in prophase and fail to execute recombination; a minority of cells (approximately 15%) complete recombination and meiosis I, and half of these form asci. Quantitative analysis of the same early meiotic transcripts that are vegetatively derepressed in the ume6 mutant, SPO11, SPO13, IME2, and SPO1, indicates a low level of induction in meiosis above their vegetative derepressed levels. In addition, the expression of later meiotic transcripts, SPS2 and DIT1, is significantly delayed and reduced. The expression pattern of early meiotic genes in ume6-deleted cells is strikingly similar to that of early meiotic genes with promoter mutations in URS1. These results support the view that UME6 and URS1 are part of a developmental switch that controls both vegetative repression and meiotic induction of meiosis-specific genes.

Structural features of the invariant chain fragment CLIP controlling rapid release from HLA-DR molecules and inhibition of peptide binding.

The invariant chain (Ii) prevents binding of ligands to major histocompatibility complex (MHC) class II molecules in the endoplasmic reticulum and during intracellular transport. Stepwise removal of the Ii in a trans-Golgi compartment renders MHC class II molecules accessible for peptide loading, with CLIP (class II-associated Ii peptides) as the final fragment to be released. Here we show that CLIP can be subdivided into distinct functional regions. The C-terminal segment (residues 92-105) of the CLIP-(81-105) fragment mediates inhibition of self- and antigenic peptide binding to HLA-DR2 molecules. In contrast, the N-terminal segment CLIP-(81-98) binds to the Staphylococcus aureus enterotoxin B contact site outside the peptide-binding groove on the alpha 1 domain and does not interfere with peptide binding. Its functional significance appears to lie in the contribution to CLIP removal: the dissociation of CLIP-(81-105) is characterized by a fast off-rate, which is accelerated at endosomal pH, whereas in the absence of the N-terminal CLIP-(81-91), the off-rate of C-terminal CLIP-(92-105) is slow and remains unaltered at low pH. Mechanistically, the N-terminal segment of CLIP seems to prevent tight interactions of CLIP side chains with specificity pockets in the peptide-binding groove that normally occurs during maturation of long-lived class II-peptide complexes.

Multiple loci govern the bone marrow-derived immunoregulatory mechanism controlling dominant resistance to autoimmune orchitis.

The existence of immunoregulatory genes conferring dominant resistance to autoimmunity is well documented. In an effort to better understand the nature and mechanisms of action of these genes, we utilized the murine model of autoimmune orchitis as a prototype. When the orchitis-resistant strain DBA/2J is crossed with the orchitis-susceptible strain BALB/cByJ, the F1 hybrid is completely resistant to the disease. By using reciprocal radiation bone marrow chimeras, the functional component mediating this resistance was mapped to the bone marrow-derived compartment. Resistance is not a function of either low-dose irradiation- or cyclophosphamide (20 mg/kg)-sensitive immunoregulatory cells, but can be adoptively transferred by primed splenocytes. Genome exclusion mapping identified three loci controlling the resistant phenotype. Orch3 maps to chromosome 11, whereas Orch4 and Orch5 map to the telomeric and centromeric regions of chromosome 1, respectively. All three genes are linked to a number of immunologically relevant candidate loci. Most significant, however, is the linkage of Orch3 to Idd4 and Orch5 to Idd5, two susceptibility genes which play a role in autoimmune insulin-dependent type 1 diabetes mellitus in the nonobese diabetic mouse.

Aod1, the immunoregulatory locus controlling abrogation of tolerance in neonatal thymectomy-induced autoimmune ovarian dysgenesis, maps to mouse chromosome 16.

Mice thymectomized at three days of age (D3Tx) develop during adulthood a variety of organ-specific autoimmune diseases, including autoimmune ovarian dysgenesis (AOD). The phenotypic spectrum of AOD is characterized by the development of anti-ovarian autoantibodies, oophoritis, and atrophy. The D3Tx model of AOD is unique in that disease induction depends exclusively on perturbation of the normal developing immune system, is T-cell-mediated, and is strain specific. For example, D3Tx A/J mice are highly susceptible to AOD, whereas C57BL/6J mice are resistant. After D3Tx, self ovarian antigens, expressed at physiological levels, trigger an autoimmune response capable of eliciting disease. The D3Tx model provides, therefore, the opportunity to focus on the mechanisms of self-tolerance that are relevant to disease pathogenesis. Previous studies indicate that the principal mechanisms involved in AOD susceptibility are genetically controlled and govern developmental processes associated with the induction and maintenance of peripheral tolerance. We report here the mapping of the Aod1 locus to mouse chromosome 16 within a region encoding several loci of immunologic relevance, including scid, Igl1, VpreB, Igll, Igl1r, Mtv6 (Mls-3), Ly-7, Ifnar, and Ifgt.

The Impact of Transit Oriented Development on the Travel Behaviors of Workers in Denver, Colorado

To combat unsustainable transportation systems characterized by reliance on petroleum, polluting emissions, traffic congestion and suburban sprawl, planners encourage mixed use, densely populated areas that provide individuals with opportunities to live, work, eat and shop without necessarily having to drive private automobiles to accommodate their needs. Despite these attempts, the frequency and duration of automobile trips has consistently increased in the United States throughout past decades. While many studies have focused on how residential proximity to transit influences travel behavior, the effect of workplace location has largely been ignored. This paper asks, does working near a TOD influence the travel behaviors of workers differently than workers living near a TOD? We examine the non-work travel behaviors of workers based upon their commuting mode and proximity to TODs. The data came from a 2009 travel behavior survey by the Denver Regional Council of Governments, which contains 8,000 households, 16,000 individuals, and nearly 80,000 trips. We measure sustainable travel behaviors as reduced mileage, reduced number of trips, and increased use of non-automobile transportation. The results of this study indicate that closer proximity of both households and workplaces to TODs decrease levels of car commuting and that non-car commuting leads to more sustainable personal travel behaviors characterized by more trips made with alternative modes.

Using the R-PAS' Aggressive Content Score For the Evaluation of Aggressive Behaviors in Children

The Rorschach Performance Assessment System (R-PAS) was developed in 2011 as analternative to the previous Comprehensive System. The goal was to improve the psychometrics,and particularly the validity, of this assessment method. The norms for children werequestionable in the Comprehensive system (e.g., outdated, low numbers of subjects) and validitystudies for children were sparse. One of the indicators included in the R-PAS system, theaggressive content indicator (AgC), is intended to reflect aggressive behavior, but few studieshave examined the validity of this indicator. This study examined the validity of AgC in asample of 32 children and adolescents receiving services at a residential treatment center.Subjects' AgC scores were analyzed in relation to demographics and diagnosis, as well as ratingsof aggression and conduct problems from the Behavioral Assessment System for Children-2(BASC-2) Parent and Teacher Reports. Correlations between the AgC score and BASC-2aggression and conduct problems scores were not statistically significant. None of thecorrelations between AgC score and a diagnosis of Conduct Disorder, Oppositional DefiantDisorder, Posttraumatic Stress Disorder, or Mood Disorders were significant either. Given thesmall sample size, null results may be a result of power concerns. The lack of significantcorrelations may however, indicate that operational definitions of aggression used in variousforms of measurement reflect different constructs.

How Language and Stereotypes Affect the Help-Seeking Behaviors of Victims of Female-on-Female Sexual Assault

While much attention has been paid to the experiences of the female victims of male-perpetrated sexual assault, relatively little attention has been paid to the experiences of female-on-female sexual assault. However, female-on-female sexual assault can and does occur within lesbian and queer communities. What literature there is on the topic demonstrates that gender stereotypes, as well as stereotypes about the lesbian and queer communities, play a role in the decision process to seek help. This paper seeks to analyze the role of language and stereotypes in the help-seeking behaviors of victims of female-on-female sexual assault, using Relational Frame Theory as a framework.

Restrictive and Expansive Views of Equality: A Grounded Theory Study that Explores the Influence of Racial Consciousness on the Behaviors of White Faculty in the Classroom

Attempts to address the ever increasing achievement gap among students have failed to explain how and why educational traditions and teaching practices perpetuate the devaluing of some and the overvaluing of others. This predicament, which plagues our educational system, has been of increased concern, given the growing racial diversity among college students and the saturation of White faculty in the academy. White faculty make up the majority, 79%, of all faculty in the academy. White faculty, whether consciously or unconsciously, are less likely to interrogate how race and racism both privilege them within the academy and influence their faculty behaviors. The result of this cyclical, highly cemented process suggests that there is a relationship between racial consciousness and White faculty members' ability to employ behaviors in their classroom that promote equitable educational outcomes for racially minoritized students. An investigation of the literature revealed that racial consciousness and the behaviors of White faculty in the classroom appeared to be inextricably linked. A conceptual framework, Racial Consciousness and Its Influence on the Behaviors of White Faculty in the Classroom was developed by the author and tested in this study. Constructivist grounded theory was used to explore the role White faculty believe they play in the dismantling of the white supremacy embedded in their classrooms through their faculty behaviors. A substantive theory subsequently emerged. Findings indicate that White faculty with a higher level of racial consciousness employ behaviors in their classroom reflective of a more expansive view of equality in their pursuit of social justice, which they consider synonymous with excellence in teaching. This research bears great significance to higher education research and practice, as it is the first of its kind to utilize critical legal scholar Kimberlé Crenshaw's (1988) restrictive and expansive views of equality framework to empirically measure and describe excellence in college teaching. Implications for faculty preparation and continued education are also discussed.

Effects of a training program to enhance autonomy supportive behaviors among youth soccer coaches

This study aimed to evaluate the prevalence and implementation of a training emphasizing the use of autonomy supportive coaching behaviors among youth soccer coaches in game-play situations as well as evaluating its effects on motivational processes among athletes. Participants included youth sport soccer coaches and their intact teams. Coaches received a series of autonomy-supportive coaching training interventions based on successful programs in general and physical education (Reeve, Jang, Carrell, Jeon & Barch, 2004; Cheon, Reeve & Moon, 2012). Athletes completed questionnaires to assess perceived autonomy support, basic need satisfaction, and motivation (Harris & Watson, 2011). Observations indicated coaches were not able to significantly modify their behaviors, yet reflectively reported modest implementation of autonomy supportive behaviors. Coaches believed the training influenced their coaching style/philosophy in regards to the coach-athlete relationship and communication styles, emphasizing choice and rationales. Continued research is needed to enhance use of autonomy supportive behaviors with volunteer coaches in a youth sport environment.

Coach Behaviors and Athlete Satisfaction in Team and Individual Sports

The coach can have a profound impact on athlete satisfaction, regardless of the level of sport involvement. Previous research has identified differences between coaching behavior preferences in team and individual sport athletes. The present study examined the moderating effect that an athlete's sport type (i.e., individual or team) may have on the relationships among seven coaching behaviors (mental preparation, technical skills, goal setting, physical training, competition strategies, personal rapport, and negative personal rapport) for predicting coaching satisfaction. Moderated multiple regression analyses indicated that each of the seven coaching behaviors were significant main effect predictors of coaching satisfaction. However, sport type (i.e., team or individual sports) was found to moderate six of the seven relationships: mental preparation, technical skills, goal setting, competition strategies, personal rapport, and negative personal rapport in predicting satisfaction with the coach. These findings indicate that high coaching satisfaction for athletes in team sports is influenced to a greater extent by the demonstration of these behaviors than it is for individual sport athletes.

Effective Behaviors of Expert Rowing Coaches: A Qualitative Investigation of Canadian Athletes and Coaches

Ten Canadian expert rowing coaches and 10 Canadian elite rowers were interviewed regarding their perceptions of effective coaching behaviors. The questions of the interview guide focused on coaches' behaviors in training, competition, and organization settings. Qualitative data analyses revealed seven behaviors elicited by coaches and athletes. Effective coaching behaviors perceived as important by both athletes and coaches were; 1) plan proactively, 2)create a positive training environment, 3)facilitate goal setting, 4)build athletes' confidence, 5) teach skills effectively, 6)recognize individual differences, and 7)establish a positive rapport with each athlete.