RESUMEN
Budding yeast cells have the capacity to adopt few but distinct physiological states depending on environmental conditions. Vegetative cells proliferate rapidly by budding while spores can survive prolonged periods of nutrient deprivation and/or desiccation. Whether or not a yeast cell will enter meiosis and sporulate represents a critical decision that could be lethal if made in error. Most cell fate decisions, including those of yeast, are understood as being triggered by the activation of master transcription factors. However, mechanisms that enforce cell fates posttranscriptionally have been more difficult to attain. Here, we perform a forward genetic screen to determine RNA-binding proteins that affect meiotic entry at the posttranscriptional level. Our screen revealed several candidates with meiotic entry phenotypes, the most significant being RIE1, which encodes an RRM-containing protein. We demonstrate that Rie1 binds RNA, is associated with the translational machinery, and acts posttranscriptionally to enhance protein levels of the master transcription factor Ime1 in sporulation conditions. We also identified a physical binding partner of Rie1, Sgn1, which is another RRM-containing protein that plays a role in timely Ime1 expression. We demonstrate that these proteins act independently of cell size regulation pathways to promote meiotic entry. We propose a model explaining how constitutively expressed RNA-binding proteins, such as Rie1 and Sgn1, can act in cell fate decisions both as switch-like enforcers and as repressors of spurious cell fate activation.
Asunto(s)
Meiosis , Proteínas de la Membrana , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae , Puntos de Control del Ciclo Celular , Diferenciación Celular/genética , Tamaño de la Célula , Meiosis/genética , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de la Membrana/genéticaRESUMEN
Despite the high profile of fertility care and assisted reproductive technologies, their social and regulatory contexts remain largely unexplored. Yet, studies reveal a practice of candidate screening on a somewhat arbitrary basis. Examining the above issues is of special importance to Israel, given its high fertility rates. To this end, this study conducted a survey of physicians' attitudes regarding access to fertility care and treatment. An anonymous questionnaire was distributed among IVF providers in all fertility clinics in Israel during 2008-2009. A total of 46 physicians (>40%) responded. Although all agree that every person has a right to procreate, 15.25% believe it is important to screen candidates and 55.6% believe they should consider non-medical criteria when providing care. Only 47.8% of physicians acknowledge the existence of guidelines in their units, but where they exist, 22.5% state they do not follow them. Furthermore, between 24.4-63.0% of physicians are willing to perform controversial procedures if backed by official guidelines. In conclusion, existing guidelines are often vague or ignored. Contrary to the USA, IVF providers in Israel are shaped by the pro-natalist approach highly encouraged by the state and they act less as trustees and gatekeepers to the future child.
Asunto(s)
Actitud del Personal de Salud , Ética , Accesibilidad a los Servicios de Salud , Infertilidad/terapia , Médicos/psicología , Técnicas Reproductivas Asistidas/psicología , Adulto , Difusión de Innovaciones , Femenino , Adhesión a Directriz , Administradores de Instituciones de Salud/psicología , Humanos , Infertilidad/psicología , Israel , Masculino , Política Organizacional , Rol del Médico/psicología , Guías de Práctica Clínica como Asunto , Negativa al Tratamiento , Derechos Sexuales y Reproductivos/psicología , Encuestas y CuestionariosRESUMEN
BACKGROUND: Although both assisted reproduction technologies (ART) and adoption services are designed to help childless couples, their legal status is overwhelmingly different. In particular, applicants for adoption services in Israel are required to undergo a meticulous background check, whereas ART has no such precondition. The present study evaluated the attitude of gynecologists in Israel towards this difference and their opinion of their own responsibility to children born by in vitro fertilization (IVF) treatment. METHODS: One hundred and eighty-one gynecologists were asked to complete a questionnaire covering their opinions on the acceptance of applicants for IVF programs compared to adopting couples and their professional responsibility to children born by IVF. RESULTS: Average age of the responders was 47.9+/-9.2 years; 75% were male; average number of own children was 2.6+/-1.3. Sixty-one percent believed that the use of IVF conferred a duty upon the physician to ensure the well-being of the future child, and 66% believed it important to somehow screen potential parents. Forty percent favored equalizing the preconditions for IVF candidates and adopting couples. Thirty-five percent supported changing the adoption laws to make the process easier, and 33% supported changing the IVF program to prevent unsuitable candidates from starting therapy. Among the latter, a strong marital bond was considered important by 17%, health status of the potential parents by 72%, and possession of a criminal record by 35%. Forty percent favored parental evaluation by a social worker, and 66%, by a psychological assessment. Only 24% thought that economic status was important. CONCLUSIONS: Most gynecologists in ART programs believe they have a duty to look out for the unborn child. Approximately one-third support the institution of changes in parental evaluation to facilitate the adoption process and to provide more restrictions in ART programs. Most believed that parental evaluation, preferably by a psychological assessment, is important prior to starting an IVF program.