Biology subjects

Amberg, N.

Publications and source records attributed to Amberg, N..

4 recordsLinked to original sources

bioRxiv2026

Pten Orchestrates Neurogenic Radial Glia Lineage Progression and Tunes Neocortical Astrocyte Production

The cerebral cortex consists of immense numbers of neuronal and glial cell-types derived from radial glial progenitor (RGP) cells. How RGPs generate appropriate quantities of distinct cortical cell-types to safeguard a brain of correct size, is not well understood. However, genetic aberration in human, including mutations in PTEN, lead to cortical malformation such as macrocephaly, albeit with unknown etiology. Here we utilized Mosaic Analysis with Double Markers (MADM)-based clonal analysis and single cell phenotyping to decipher the role of Pten in neurogenic and gliogenic RGP lineage progression during cortical ontogeny. While neurogenic RGP lineage progression and projection neuron production was moderately altered in the absence of Pten, cortical astrocyte production was drastically increased. Through genetic epistasis experiments we show that the loss of Pten uncouples astrocyte generation from essential growth factor signaling hubs, funneling into MAPK. Collectively, our results suggest that Pten regulates RGP lineage progression with distinct sequential functions in cortical projection neurogenesis and astrocyte production to ensure the emergence of a correctly-sized cerebral cortex.

neuroscience↗

bioRxiv2022

Large neutral amino acid levels tune perinatal neuronal excitability and survival

Surprisingly little is known about the critical metabolic changes that neural cells have to undergo during development and how even mild, temporary shifts in this program can influence brain circuitries and behavior. Inspired by the discovery that mutations in SLC7A5, a transporter of metabolically-relevant large neutral amino acids, lead to a form of autism spectrum disorder, we employed metabolomic profiling to study the metabolic states of the cerebral cortex across different stages of life. We found that the cerebral cortex undergoes significant metabolic remodeling throughout development, with certain groups of metabolites showing stage-specific changes. But what are the consequences of interfering with this metabolic program? By manipulating Slc7a5 expression in neural cells, we found that the metabolism of large neutral amino acids and lipids in the cerebral cortex are highly interconnected. Deletion of Slc7a5 in neurons perturbs specifically the postnatal metabolic state leading to a shift in lipid metabolism and a stage- and cell-type-specific alteration in neuronal activity patterns, resulting in a long-term cortical circuit dysfunction.

neuroscience↗

bioRxiv2022

Tissue-wide Genetic and Cellular Landscape Shapes the Execution of Sequential PRC2 Functions in Neural Stem Cell Lineage Progression

The generation of a correctly-sized cerebral cortex with all-embracing neuronal and glial cell-type diversity critically depends on faithful radial glial progenitor (RGP) cell proliferation/differentiation programs. Temporal RGP lineage progression is regulated by Polycomb Repressive Complex 2 (PRC2) and loss of PRC2 activity results in severe neurogenesis defects and microcephaly. How PRC2-dependent gene expression instructs RGP lineage progression is unknown. Here we utilize Mosaic Analysis with Double Markers (MADM)-based single cell technology and demonstrate that PRC2 is not cell-autonomously required in neurogenic RGPs but rather acts at the global tissue-wide level. Conversely, cortical astrocyte production and maturation is cell-autonomously controlled by PRC2-dependent transcriptional regulation. We thus reveal highly distinct and sequential PRC2 functions in RGP lineage progression that are dependent on complex interplays between intrinsic and tissue-wide properties. In a broader context our results imply a critical role for the genetic and cellular niche environment in neural stem cell behavior.

neuroscience↗

bioRxiv2020

A Genome-wide Library of MADM Mice for Single-Cell Genetic Mosaic Analysis

Mosaic Analysis with Double Markers (MADM) offers a unique approach to visualize and concomitantly manipulate genetically-defined cells in mice with single-cell resolution. MADM applications include the analysis of lineage; single-cell morphology and physiology; genomic imprinting phenotypes; and dissection of cell-autonomous gene functions in vivo in health and disease. Yet, MADM could only be applied to <25% of all mouse genes on select chromosomes thus far. To overcome this limitation, we generated transgenic mice with knocked-in MADM cassettes near the centromeres of all 19 autosomes and validated their use across organs. With this resource, >96% of the entire mouse genome can now be subjected to single-cell genetic mosaic analysis. Beyond proof-of-principle, we applied our MADM library to systematically trace sister chromatid segregation in distinct mitotic cell lineages. We found striking chromosome-specific biases in segregation patterns, reflecting a putative mechanism for the asymmetric segregation of genetic determinants in somatic stem cell division.

developmental biology↗