Transcription templated assembly of the nucleolus in the C. elegans embryo.

The nucleolus is a multicomponent structure made of RNA and proteins that serves as the site of ribosome biogenesis within the nucleus. It has been extensively studied as a prototype of a biomolecular condensate whose assembly is driven by phase separation. While the steady-state size of the nucleolus is quantitatively accounted for by the thermodynamics of phase separation, we show that experimental measurements of the assembly dynamics are inconsistent with a simple model of a phase-separating system relaxing to its equilibrium state. Instead, we show that the dynamics are well described by a model in which the transcription of ribosomal RNA actively drives nucleolar assembly. We find that our model of active transcription-templated assembly quantitatively accounts for the rapid kinetics observed in early embryos at different developmental stages, and for different RNAi perturbations of embryo size. Our model predicts a scaling of the time to assembly with the volume of the nucleus to the one-third power, which is confirmed by experimental data. Our study highlights the role of active processes such as transcription in controlling the placement and timing of assembly of membraneless organelles.

The shared decision-making tool for caregivers of children with prenatal opioid exposure: A pilot and acceptability study.

This pilot and acceptability study sought to report provider acceptability and developmental concerns expressed by caregivers of children with prenatal opioid exposure using the Shared Decision-Making Tool (SDMT), an instrument created by study authors. Data were collected from five health care and early intervention providers and 83 caregivers from a medical clinic and early intervention service center. Descriptive statistics were used to identify frequency, mean level, and prioritization of developmental concerns using the SDMT, and to summarize provider acceptability about integrating the SDMT into their workflow. Communication was the most frequently cited concern in four consecutive age categories, followed by Inattention/impulsivity and Problem behavior. All providers "strongly agreed" or "agreed" with all statements on the provider feedback survey, except two instances. Results of this study support the SDMT as a potential tool to help engage caregivers and providers of children with prenatal opioid exposure in the shared decision-making process by standardizing communication related to areas of developmental concern and caregivers' priority needs. Findings from this pilot study will inform modifications to the SDMT and administration instructions before our next study, which will examine psychometric properties and caregiver acceptability of the scale.