Periodic Reporting for period 1 - TransNeuroFate (Translational Control of Neuronal Fate and Identity)
Reporting period: 2023-01-01 to 2025-06-30
The cerebral cortex is a central structure of the mammalian brain, characterized by a remarkable diversity of neuronal types. Understanding the origin of the extraordinary neuronal diversity is fundamental to understand how cortical architecture and functions emerge during development and remains a critical challenge in cellular and molecular neurobiology.
While the efforts have been focused on transcriptional control, evidence for regulation at the translational level is emerging. I hypothesize that translational control, albeit overlooked, acts in a combinatorial fashion with transcriptional induction to regulate gene expression programs during cortical patterning. I have demonstrated an intimate functional link between cortical development and pools of mature transfer RNA (tRNAs), the major determinant of translation. I, therefore, propose to address how translational control, through the modulation of the availability of mature translationally competent tRNAs, fine-tunes gene expression programs during lineage progression, thereby regulating neuronal diversity. Studying this yet unexplored question should unravel a hitherto unrecognized level of neuronal fate identity determination in the cerebral cortex.
This project should bring conceptual advances in the understanding of brain development mechanisms that could be instrumental to interpret the pathological mechanisms of neurodevelopmental disorders.
While the efforts have been focused on transcriptional control, evidence for regulation at the translational level is emerging. I hypothesize that translational control, albeit overlooked, acts in a combinatorial fashion with transcriptional induction to regulate gene expression programs during cortical patterning. I have demonstrated an intimate functional link between cortical development and pools of mature transfer RNA (tRNAs), the major determinant of translation. I, therefore, propose to address how translational control, through the modulation of the availability of mature translationally competent tRNAs, fine-tunes gene expression programs during lineage progression, thereby regulating neuronal diversity. Studying this yet unexplored question should unravel a hitherto unrecognized level of neuronal fate identity determination in the cerebral cortex.
This project should bring conceptual advances in the understanding of brain development mechanisms that could be instrumental to interpret the pathological mechanisms of neurodevelopmental disorders.
We are combining ribosome profiling, mRNA and tRNA deep sequencing, screening of genetic perturbation and gene manipulation in vivo in the mouse embryonic cortex to i) uncover the specific translational programs that influence neuronal lineages progression (Aim 1); and ii) determine how tRNA repertoires (both at the transcriptional (Aim 2) and post-transcriptional levels (Aim 3)) are shaped to meet the specific translational needs of different cell types during corticogenesis. To date, we have optimized most of the techniques required to complete the project. We have generated several datasets that are currently analyzed and integrated to better understand the role of tRNAs in brain development. We have initiated the characterization of tRNA content in the developing murine cortex and identify dynamic pattern of transfer RNA expression over time in the developing cerebral cortex. We have also pursued our investigation of functional roles of tRNA modification during the corticogenesis. We provide the first evidence for physiological roles for the ADAT2/ADAT3 complex and tRNA deamination during the development of the mammalian cerebral cortex. We propose that a critical threshold of ADAT2/ADAT3 activity is necessary to support proper neuronal development. This raises important questions about the role of I34 tRNA modifications in supporting the protein demands during brain development.
This project provides the first catalogues of tRNA pools during corticogenesis and describe the underlying regulatory mechanisms. This work sheds new light on fundamental questions in cell biology, and provide significant molecular insights into cortical neurogenesis in health and disease. It opens new questions: How do tRNA repertoires change in time in pathological scenarios? Which developmental processes are controlled by tRNAs? Which mRNAs are aberrantly translated in neuronal cells with perturbed tRNA pools? Answers to those questions are critical to interpret the pathological mechanisms that participate in the onset and the progression of neurological disorders