Biology subjects

Martina, V.

Publications and source records attributed to Martina, V..

3 recordsLinked to original sources

bioRxiv2024

Removal of developmentally regulated microexons has a minimal impact on larval zebrafish brain morphology and function

Microexon splicing is a vertebrate-conserved process through which small, often in-frame, exons are differentially included during brain development and across neuron types. Although the protein sequences encoded by these exons are highly conserved and can mediate interactions, the neurobiological functions of only a small number have been characterized. To establish a more generalized understanding of their roles in brain development, we used CRISPR/Cas9 to remove 45 microexons in zebrafish and assessed larval brain activity, morphology, and behavior. Most mutants had minimal or no phenotypes at this developmental stage. Among previously studied microexons, we uncovered baseline and stimulus-driven phenotypes for two microexons (meA and meB) in ptprd and reduced activity in the telencephalon in the tenm3 B0 isoform. Although mild neural phenotypes were discovered for several microexons that have not been previously characterized, including in ppp6r3, sptan1, dop1a, rapgef2, dctn4, vti1a, and meaf6. This study establishes a general approach for investigating conserved alternative splicing events and prioritizes microexons for downstream analysis.

neuroscience↗

bioRxiv2024

Diencephalic and Neuropeptidergic Dysfunction in Zebrafish with Autism Risk Mutations

Hundreds of human mutations are linked to autism and related disorders, yet the functions of many of these mutated genes during vertebrate neurodevelopment are unclear. We generated 27 zebrafish mutants with presumptive protein-truncating mutations or specific missense variants corresponding to autism-risk alleles in 17 human genes. We observed baseline and stimulus-driven behavioral changes at larval stages, as well as social behavior differences in lines tested as juveniles. Imaging whole-brain activity revealed a near identical activity map for mutations in the unrelated genes kmt5b and hdlbpa, defined by increased activity mainly in the diencephalon. Mutating 7 of the 17 risk genes resulted in substantial brain size differences. Using RNA sequencing, we further defined molecular drivers of the observed phenotypes, identifying targetable disruptions in neuropeptide signaling, neuronal maturation, and cell proliferation. This multi-modal screen nominated brain regions, cell types, and molecular pathways that may contribute to autism susceptibility. TeaserZebrafish screen uncovers diencephalon, social interaction, and neuropeptidergic signaling phenotypes in ASD risk mutants.

genetics↗

bioRxiv2023

The lncRNA Neat1 is associated with astrocyte reactivity and memory deficits in a mouse model of Alzheimer's disease

Dysregulation of long non-coding RNAs (lncRNAs) have been associated with Alzheimers disease (AD). However, the functional role of lncRNAs in AD remains unclear. Here, we report a crucial role for the lncRNA Neat1 in astrocyte dysfunction and memory deficits associated with AD. Transcriptomics analysis show abnormally high expression levels of NEAT1 in the brains of AD patients relative to aged-matched healthy controls, with the most significantly elevated levels in glial cells. In a human transgenic APP-J20 (J20) mouse model of AD, RNA-fluorescent in situ hybridization characterization of Neat1 expression in hippocampal astrocyte versus non-astrocyte cell populations revealed a significant increase in Neat1 expression in astrocytes of male, but not female, mice. This corresponded with increased seizure susceptibility in J20 male mice. Interestingly, Neat1 deficiency in the dCA1 in J20 male mice did not alter seizure threshold. Mechanistically, Neat1 deficiency in the dorsal area CA1 of the hippocampus (dCA1) J20 male mice significantly improved hippocampus-dependent memory. Neat1 deficiency also remarkably reduced astrocyte reactivity markers suggesting that Neat1 overexpression is associated with astrocyte dysfunction induced by hAPP/A{beta} in the J20 mice. Together, these findings indicate that abnormal Neat1 overexpression may contribute to memory deficits in the J20 AD model not through altered neuronal activity, but through astrocyte dysfunction.

neuroscience↗