RF3:GTP promotes rapid dissociation of the class 1 termination factor.

Translation termination is promoted by class 1 and class 2 release factors in all domains of life. While the role of the bacterial class 1 factors, RF1 and RF2, in translation termination is well understood, the precise contribution of the bacterial class 2 release factor, RF3, to this process remains less clear. Here, we use a combination of binding assays and pre-steady state kinetics to provide a kinetic and thermodynamic framework for understanding the role of the translational GTPase RF3 in bacterial translation termination. First, we find that GDP and GTP have similar affinities for RF3 and that, on average, the t1/2 for nucleotide dissociation from the protein is 1-2 min. We further show that RF3:GDPNP, but not RF3:GDP, tightly associates with the ribosome pre- and post-termination complexes. Finally, we use stopped-flow fluorescence to demonstrate that RF3:GTP enhances RF1 dissociation rates by over 500-fold, providing the first direct observation of this step. Importantly, catalytically inactive variants of RF1 are not rapidly dissociated from the ribosome by RF3:GTP, arguing that a rotated state of the ribosome must be sampled for this step to efficiently occur. Together, these data define a more precise role for RF3 in translation termination and provide insights into the function of this family of translational GTPases.

Visualization of the hybrid state of tRNA binding promoted by spontaneous ratcheting of the ribosome.

A crucial step in translation is the translocation of tRNAs through the ribosome. In the transition from one canonical site to the other, the tRNAs acquire intermediate configurations, so-called hybrid states. At this stage, the small subunit is rotated with respect to the large subunit, and the anticodon stem loops reside in the A and P sites of the small subunit, while the acceptor ends interact with the P and E sites of the large subunit. In this work, by means of cryo-EM and particle classification procedures, we visualize the hybrid state of both A/P and P/E tRNAs in an authentic factor-free ribosome complex during translocation. In addition, we show how the repositioning of the tRNAs goes hand in hand with the change in the interplay between S13, L1 stalk, L5, H68, H69, and H38 that is caused by the ratcheting of the small subunit.

[Bipolar disorder in adolescence]. / Trouble bipolaire de l'adolescent.

Juvenile mania is a concept widely developed but also highly debated since the 1990s. In the heart of this debate, Severe Mood Dysregulation (SMD) and "Temper Dysregulation disorder with Dysphoria" (recently integrated in DSM-5) showed their interest. Actually, the objective is to distinguish two clinical phenotypes in order to avoid confusion between (1) what would raise more of mood dysregulation with chronic manic like symptoms, and (2) bipolar disorder type I with episodic and acute manic episodes. Therapeutic stakes are major. In adolescents, even if DSM adult diagnostic criteria can be used and bipolar disorder type I clearly established, differential diagnostic at onset between acute manic episode and schizophrenia onset remain sometimes difficult to assess. Furthermore, it is crucial to better assess outcome of these adolescents, in terms of morbidity and potential prognosis factors, knowing that a younger age at onset is associated with a poorer outcome according to several adult studies. Therapeutic implications could then be drawn.

Short Report: 10-year follow-up of a boy with ARID1B-related disorder. Early intervention, longitudinal dimensional phenotype, brain imaging and outcome.

ARID1B-related disorders constitute a clinical continuum, from classic Coffin-Siris syndrome to intellectual disability (ID) with or without nonspecific dysmorphic features. Here, we describe an 11-year-old boy with an ARID1B mutation whose phenotype changed from severe developmental delay and ID to a complex neurodevelopmental disorder with multidimensional impairments, including normal intelligence despite heterogeneous IQ scores, severe motor coordination disorder, oral language disorder and attention-deficit/hyperactivity disorder. Phenotypic changes occurred after early intensive remediation and paralleled the normalization of myelination impairments, as evidenced by early brain imaging. WHAT THIS PAPER ADDS?: This report describes a 10-year multidisciplinary follow-up of a child with an ARID1B mutation who received early intensive remediation and whose phenotype changed during development. Clinical improvement paralleled the normalization of myelination impairments. This case supports a dimensional approach for complex neurodevelopmental disorders.

Transidentities and autism spectrum disorder: A systematic review.

Transidentity and autism frequently co-occur. Previous reviews have focused mainly on frequencies. Here, we conducted a systematic review to condense all the studies and themes on this co-occurrence and to offer a global view. We followed the PRISMA method and selected 77 articles (including 59 clinical studies) in April 2022. We found 5 main themes (sex ratio, theories, sexual orientation, clinical and social consequences, and care implications) in addition to frequencies. Many theories have been proposed to explain the co-occurrence. One posits that social difficulties related to autism would lead to less identification with gender norms and less pressure to conform to these norms, allowing for greater gender diversity in people with autism. Given their difficulties with social interactions and communication, the announcement of one's transidentity to one's social group is often discredited, increasing the risk of suffering and delayed care. Many reports reaffirm the importance of providing specialised care for transgender people with autism. Autism is not a contraindication for gender-affirming treatment. However, some cognitive specificities can affect the planning of care, and transgender people with autism are at high risk of discrimination and harassment. We conclude that there is a need to raise awareness about gender and autism.

Recognition of aminoacyl-tRNA: a common molecular mechanism revealed by cryo-EM.

The accuracy of ribosomal translation is achieved by an initial selection and a proofreading step, mediated by EF-Tu, which forms a ternary complex with aminoacyl(aa)-tRNA. To study the binding modes of different aa-tRNAs, we compared cryo-EM maps of the kirromycin-stalled ribosome bound with ternary complexes containing Phe-tRNA(Phe), Trp-tRNA(Trp), or Leu-tRNA(LeuI). The three maps suggest a common binding manner of cognate aa-tRNAs in their specific binding with both the ribosome and EF-Tu. All three aa-tRNAs have the same 'loaded spring' conformation with a kink and twist between the D-stem and anticodon stem. The three complexes are similarly integrated in an interaction network, extending from the anticodon loop through h44 and protein S12 to the EF-Tu-binding CCA end of aa-tRNA, proposed to signal cognate codon-anticodon interaction to the GTPase centre and tune the accuracy of aa-tRNA selection.

Mutational analysis reveals two independent molecular requirements during transfer RNA selection on the ribosome.

Accurate discrimination between cognate and near-cognate aminoacyl-tRNAs during translation relies on the specific acceleration of forward rate constants for cognate tRNAs. Such specific rate enhancement correlates with conformational changes in the tRNA and small ribosomal subunit that depend on an RNA-specific type of interaction, the A-minor motif, between universally conserved 16S ribosomal RNA nucleotides and the cognate codon-anticodon helix. We show that perturbations of these two components of the A-minor motif, the conserved rRNA bases and the codon-anticodon helix, result in distinct outcomes. Although both cause decreases in the rates of tRNA selection that are rescued by aminoglycoside antibiotics, only disruption of the codon-anticodon helix is overcome by a miscoding tRNA variant. On this basis, we propose that two independent molecular requirements must be met to allow tRNAs to proceed through the selection pathway, providing a mechanism for exquisite control of fidelity during this step in gene expression.

[Specificities and non-specificities of the accompaniment of transgender and/or questioning people]. / Spécificités et non-spécificités de l'accompagnement des personnes transgenres et/ou en questionnement.

Gender transitions have been taking place in France for more than fifty years. Recently, case law has come to fruition and has further strengthened the rights of transgender people. However, the issues related to being transgender, including in the medical field, remain too often unknown. This article reports on the specificities and non-specificities of the transidentitarian experience.

Examining the hikikomori syndrome in a French sample of hospitalized adolescents with severe social withdrawal and school refusal behavior.

While the term hikikomori (HKM) has spread internationally to describe a chronic and severe form of social withdrawal, its place in current nosography and its transposition into non-Asian cultures are still debated. A retrospective chart review was conducted to determine the rate and the clinical profiles of HKM among a French sample of adolescent inpatients. Data were obtained from 191 adolescents aged 12-18 years (M = 15.0, 44% boys) consecutively admitted in two inpatient units from January 2017 to December 2019. Using a retrospective diagnosis of HKM based on Teo and Gaw's criteria, we compared socio-demographic characteristics, clinical features, and treatment outcomes between HKM patients and those with other forms of social withdrawal and/or school refusal (SW/SR). At admission, 7% of participants met HKM criteria (n = 14, M = 14.3, 64% boys), one out of six adolescents with SW/SR. Among those with SW/SR, HKM + vs. HKM- participants had higher rates of anxiety disorder (Odd Ratio, OR = 35.2) and lower disruptive behavioral disorder (OR = 0.03). A minority of the participants with anxiety and depressive disorders met the HKM criteria (respectively, 15% and 9%), but those with HKM had a longer duration of symptoms, longer hospitalization, and required more daily care facilities at discharge compared to HKM-. While HKM syndrome could not be delimitated from anxiety disorder, it was associated with specific clinical features and treatment outcomes. The clinical characteristics observed were consistent with the features reported in Asian HKM adults, supporting face validity of this clinical concept in adolescent inpatients with different cultural contexts.

The hybrid state of tRNA binding is an authentic translation elongation intermediate.

The GTPase elongation factor (EF)-G is responsible for promoting the translocation of the messenger RNA-transfer RNA complex on the ribosome, thus opening up the A site for the next aminoacyl-tRNA. Chemical modification and cryo-EM studies have indicated that tRNAs can bind the ribosome in an alternative 'hybrid' state after peptidyl transfer and before translocation, though the relevance of this state during translation elongation has been a subject of debate. Here, using pre-steady-state kinetic approaches and mutant analysis, we show that translocation by EF-G is most efficient when tRNAs are bound in a hybrid state, supporting the argument that this state is an authentic intermediate during translation.

"It Is Not the Robot Who Learns, It Is Me." Treating Severe Dysgraphia Using Child-Robot Interaction.

Writing disorders are frequent and impairing. However, social robots may help to improve children's motivation and to propose enjoyable and tailored activities. Here, we have used the Co-writer scenario in which a child is asked to teach a robot how to write via demonstration on a tablet, combined with a series of games we developed to train specifically pressure, tilt, speed, and letter liaison controls. This setup was proposed to a 10-year-old boy with a complex neurodevelopmental disorder combining phonological disorder, attention deficit/hyperactivity disorder, dyslexia, and developmental coordination disorder with severe dysgraphia. Writing impairments were severe and limited his participation in classroom activities despite 2 years of specific support in school and professional speech and motor remediation. We implemented the setup during his occupational therapy for 20 consecutive weekly sessions. We found that his motivation was restored; avoidance behaviors disappeared both during sessions and at school; handwriting quality and posture improved dramatically. In conclusion, treating dysgraphia using child-robot interaction is feasible and improves writing. Larger clinical studies are required to confirm that children with dysgraphia could benefit from this setup.

Peptide release on the ribosome depends critically on the 2' OH of the peptidyl-tRNA substrate.

Peptide release on the ribosome is catalyzed by protein release factors (RFs) on recognition of stop codons positioned in the A site of the small ribosomal subunit. Here we show that the 2' OH of the peptidyl-tRNA substrate plays an essential role in catalysis of the peptide release reaction. These observations parallel earlier studies of the mechanism of the peptidyl transfer reaction and argue that related mechanisms are at the heart of catalysis for these reactions.

Transgender fathering: Children's psychological and family outcomes.

Medical advances in assisted reproductive technology have created new ways for transgender persons to become parents outside the context of adoption. The limited empirical data does not support the idea that trans-parenthood negatively impacts children's development. However, the question has led to lively societal debates making the need for evidence-based studies urgent. We aimed to compare cognitive development, mental health, gender identity, quality of life and family dynamics using standardized instruments and experimental protocols in 32 children who were conceived by donor sperm insemination (DSI) in French couples with a cisgender woman and a transgender man, the transition occurring before conception. We constituted two control groups matched for age, gender and family status. We found no significant difference between groups regarding cognitive development, mental health, and gender identity, meaning that neither the transgender fatherhood nor the use of DSI had any impact on these characteristics. The results of the descriptive analysis showed positive psycho-emotional development. Additionally, when we asked raters to differentiate the family drawings of the group of children of trans-fathers from those who were naturally conceived, no rater was able to differentiate the groups above chance levels, meaning that what children expressed through family drawing did not indicate cues related to trans-fatherhood. However, when we assessed mothers and fathers with the Five-Minute Speech Sample, we found that the emotions expressed by transgender fathers were higher than those of cisgender fathers who conceived by sex or by DSI. We conclude that the first empirical data regarding child development in the context of trans-parenthood are reassuring. We believe that this research will also improve transgender couple care and that of their children in a society where access to care remains difficult in this population. However, further research is needed with adolescents and young adults.

The Developmental Implications of the Use of Reproductive Technologies for Transgender People: A Comparative Cross-Section Protocol.

BACKGROUND: Today, individuals and couples with fertility issues can use advances in biomedical technologies to conceive. Transgender persons also benefit from these advances and can not only actualize their self-identified gender identities but also experience parenthood. These strategies for persons to self-actualize and to access parenthood have improved the condition of transgender persons. However, some may question the welfare of the offspring because such transfamily forms are often confusing to many. The sparse research on the psychological well-being of children of transgender people is reassuring. However, the limited empirical research justifies more studies to be conducted with an evidence-based methodology to assess whether these new methods of parenting have any adverse impact on children. AIMS: The current report details the protocol we built to compare cognitive development, mental health, gender identity, quality of life, and family dynamics in children of transgender fathers and donor sperm insemination (DSI) and two control groups matched for age and gende typically developing (TD) children and children from cisgender parents and DSI. HYPOTHESIS: To calculate sample sizes, we hypothesize no significant difference between groups. SUBJECTS AND METHODS: Since 2008, married couples that include a transgender father have been able to access DSI and have started conceiving children in France. They are always invited to participate in research to assess their children's well-being. To date, the cohort includes 53 children in 37 families. We propose to carry out a cross-sectional comparative study exploring cognitive development with the Brunet-Lézine Psychomotor Development Scale or Wechsler's Intelligence Scales according to age; mental health with the Child Behaviour Checklist; gender identity with the Gender Identity Interview for Children; quality of life with the KIDSCREEN and the Adolescent Coping Questionnaire; and family dynamics with the Parental Bonding Instrument, the Inventory of Parent and Peer Attachment, the Five-Minute Speech Sample, and Corman's Family Drawing Test. To assess possible subtle differences between children's family drawings, we will use a generalization of the "lady-tasting-tea" procedure to link qualitative and quantitative approaches in psychiatric research. Twenty raters [four child and family psychoanalysts (CHILDPSY), four adult psychiatrists (ADUPSY), four biologists working in assistive reproduction technology (BIOL), four endocrinologists working with transgender individuals (ENDOC), and four students (STUD)] will be randomly shown the drawings and asked to blindly classify them using a Likert scale according to whether the child has a transgender father. STATISTICAL ANALYSIS: After testing normality, comparisons between the three groups will be performed with appropriate statistical tests (Kruskal-Wallis, ANOVA, Chi2 or Fisher's exact test). For the "lady-tasting-tea" procedure, we will use a permutation test. ETHICS: The study protocol has been approved by the CERES (Comité d'Ethique de Recherche en Santé) of Paris 5 University. Registration number is 2015/31.

Phenomenology, socio-demographic factors and outcome upon discharge of manic and mixed episodes in hospitalized adolescents: a chart review.

BACKGROUND: The existence of bipolar disorder type I (BD-I) during adolescence is now clearly established whereas there are still some controversies on BD-II and BD-NOS diagnosis, mainly in Europe (O'Dowd in Br Med J 29, 2006). Little is known on the phenomenology and potential short-term prognosis factors of bipolar episodes in this age population. In particular, very few studies examine this issue on inpatients in the European context of free access to care. OBJECTIVE: To describe the phenomenology of acute manic and mixed episodes in hospitalized adolescents and to analyse potential predictive factors associated with clinical improvement at discharge and length of hospitalization. METHODS: A total of 80 subjects, aged 12-20 years, consecutively hospitalized for a manic or mixed episode. Socio-demographic and clinical data were extracted by reviewing patients' charts. We used a multivariate analysis to evaluate short-term outcome predictors. RESULTS: The sample was characterized by severe impairment, high rates of psychotic features (N = 50, 62.5%), a long duration of stay (mean 80.4 days), and an overall good improvement (86% very much or much improved). Thirty-three (41.3 %) patients had a history of depressive episodes, 13 (16.3%) had manic or brief psychotic episodes but only 3 (3.7%) had a history of attention deficit/hyperactivity disorders. More manic episodes than mixed episodes were identified in subjects with mental retardation (MR) and in subjects from migrant and/or low socio-economic families. Overall severity and female gender predicted better improvement in GAF scores. Poor insight and the existence of psychotic features predicted longer duration of stay. CONCLUSION: These results suggest that severe manic and mixed episodes in adolescents with BD-I need prolonged inpatient care to improve and that socio-cultural factors and MR should be examined more closely in youth with BD.

LdtMav2, a nonclassical transpeptidase and susceptibility of Mycobacterium avium to carbapenems.

AIM: Mycobacterium avium infections, especially in immune-compromised individuals, present a significant challenge as therapeutic options are limited. In this study, we investigated if M. avium genome encodes nonclassical transpeptidases and if newer carbapenems are effective against this mycobacteria. MATERIALS & METHODS: Biochemical and microbiological approaches were used to identify and characterize a nonclassical transpeptidase, namely L,D-transpeptidase, in M. avium. RESULTS & CONCLUSION: We describe the biochemical and physiological attributes of a L,D-transpeptidase in M. avium, LdtMav2. Suggestive of a constitutive requirement, levels of LdtMav2, a L,D-transpeptidase in M. avium, remain constant during exponential and stationary phases of growth. Among ß-lactam antibacterials, only a subset of carbapenems inhibit LdtMav2 and tebipenem, a new oral carbapenem, inhibits growth of M. avium.

Ecological Momentary Assessment and Smartphone Application Intervention in Adolescents with Substance Use and Comorbid Severe Psychiatric Disorders: Study Protocol.

CONTEXT: Substance use disorders (SUDs) are highly prevalent among inpatient adolescents with psychiatric disorders. In this population, substance use and other psychiatric outcomes can reinforce one another. Despite the need for integrated interventions in youths with dual diagnoses, few specific instruments are available. App-based technologies have shown promising results to help reduce substance use in adolescents, but their applicability in youths with associated severe psychiatric disorders is poorly documented. We aim to evaluate the feasibility of an ecological momentary assessment (EMA) intervention for all substance users, and of a smartphone application for cannabis users (Stop-Cannabis), for outpatient treatment after hospital discharge. METHODS AND ANALYSIS: All inpatient adolescents with psychiatric disorders hospitalized between 2016 and 2018 in a university hospital will be systematically screened for SUD and, if positive, will be assessed by an independent specialist addiction team. Participants with confirmed SUDs will be invited and helped to download an EMA app and, if required, the Stop-Cannabis app, the week preceding hospital discharge. Information about the acceptability and use of both apps and the validity of EMA data in comparison to clinical assessments will be assessed after 6 months and 1 year. DISCUSSION: This research has been designed to raise specific issues for consideration regarding the sequence between substance use, contextual factors, and other psychiatric symptoms among adolescents with comorbid severe psychiatric disorders. A better understanding of the mechanisms involved will inform the development of integrated treatment for dual disorders at that age. ETHICS AND DISSEMINATION: The study has already been approved and granted. Dissemination will include presentations at international congresses as well as publications in peer-reviewed journals. TRIAL REGISTRATION: European Clinical Trials Database: Number 2016-001999-30.

EFG-independent translocation of the mRNA:tRNA complex is promoted by modification of the ribosome with thiol-specific reagents.

Translation of polyphenylalanine from a polyuridine template by the ribosome in the absence of the elongation factors EFG and EFTu (and the energy derived from GTP hydrolysis) is promoted by modification of the ribosome with thiol-specific reagents such as para-chloromercuribenzoate (pCMB). Here, we examine the translational cycle of modified ribosomes and show that peptide bond formation and tRNA binding are largely unaffected, whereas translocation of the mRNA:tRNA complex is substantially promoted by pCMB modification. The translocation movements that we observe are authentic by multiple criteria including the processivity of translation, accuracy of movement (three-nucleotide) along a defined mRNA template and sensitivity to antibiotics. Characterization of the modified ribosomes reveals that the protein content of the ribosomes is not depleted but that their subunit association properties are severely compromised. These data suggest that molecular targets (ribosomal proteins) in the interface region of the ribosome are critical barriers that influence the translocation of the mRNA:tRNA complex.

Ribosomes slide on lysine-encoding homopolymeric A stretches.

Protein output from synonymous codons is thought to be equivalent if appropriate tRNAs are sufficiently abundant. Here we show that mRNAs encoding iterated lysine codons, AAA or AAG, differentially impact protein synthesis: insertion of iterated AAA codons into an ORF diminishes protein expression more than insertion of synonymous AAG codons. Kinetic studies in E. coli reveal that differential protein production results from pausing on consecutive AAA-lysines followed by ribosome sliding on homopolymeric A sequence. Translation in a cell-free expression system demonstrates that diminished output from AAA-codon-containing reporters results from premature translation termination on out of frame stop codons following ribosome sliding. In eukaryotes, these premature termination events target the mRNAs for Nonsense-Mediated-Decay (NMD). The finding that ribosomes slide on homopolymeric A sequences explains bioinformatic analyses indicating that consecutive AAA codons are under-represented in gene-coding sequences. Ribosome 'sliding' represents an unexpected type of ribosome movement possible during translation.

One-dimensional SDS-polyacrylamide gel electrophoresis (1D SDS-PAGE).

This protocol describes a denaturing polyacrylamide gel system utilizing sodium dodecyl sulfate (SDS) to separate protein molecules based on size as first described by Laemmli (1970). SDS-PAGE can be used to monitor protein purifications, check the purity of samples, and to estimate molecular weights for unknown proteins.