Daina Bujanauskienė has defended her thesis entitled "Molecular profiling of synapses during brain circuit refinement" for the degree of Doctor of Science in Biochemistry.
The scientific supervisor is Prof. Dr. Urtė Neniškytė
Composition of the Dissertation Defense Board:
Chairperson - Prof. Dr. Vilmantė Borutaitė (Lithuanian University of Health Sciences, Natural Sciences, Biochemistry); Dr. Etienne Herzog (Bordeaux University, France, Natural Sciences, Biophysics); Dr. Giancarlo Russo (Vilnius University, Natural Sciences, Biochemistry); Dr. Giedrius Steponaitis (Lithuanian University of Health Sciences, Natural Sciences, Biology); Dr. Giedrė Valiulienė (Vilnius University, Natural Sciences, Biochemistry).
Critical periods, characterized by heightened synaptic plasticity, are crucial for proper brain development. After these periods, plasticity diminishes. Recent studies highlight the potential role of localized synaptic protein synthesis in regulating this process. During critical plasticity periods, the dynamic formation and elimination of synapses depend on molecular signals, such as externalized phosphatidylserine (PS). However, the biochemical processes within synapses that initiate their removal remain unclear.
Synaptosomes - isolated excitatory synapses - were analyzed to investigate changes in the local transcriptome during critical periods of brain development. These samples showed reduced ribosomal RNA (rRNA) levels, rendering traditional RNA integrity assessment methods unsuitable. A 5′:3′ method based on the PGK1 transcript was developed for reliable mRNA integrity evaluation in synapses. mRNA sequencing analysis revealed that synaptic transcripts primarily regulate cellular transport, synaptic signaling, and local protein synthesis. Furthermore, dynamic transcriptome changes occur during cortical development.
An FS marker based on the C2 domain of lactadherin (MFG-E8) was also developed to visualize and quantify PS on synapses. This study provides new insights into synaptic plasticity and introduces novel tools for studying brain development and remodeling processes.
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