tophome

E-poster

Session: 3

PS3-13 | CHARACTERIZING THE NANOSCALE ORGANIZATION OF THE ACTIN/SPECTRIN MEMBRANE-ASSOCIATED PERIODIC SKELETON IN RODENT NERVES USING 3D-STORM MICROSCOPY

Nahir Guadalupe Gazal

Laboratorio de Neurociencias / Instituto de Investigación Médica Mercedes y Martín Ferreyra (INIMEC- CONICET- UNC)

It has been recently discovered that axons and dendrites possess a particular arrangement of their cortical skeleton, referred to as the Membrane-associated actin/spectrin Periodic Skeleton (MPS). The MPS is a periodic protein structure consisting of actin “rings” located transversely to the axon and separated every 190 nm by α/β-spectrin tetramers “spacers”. The MPS can only be described using super-resolution (SR) microscopy approaches, since its spatial features lay below the diffraction limit of light. Most of published studies describe the MPS in vitro (in cultured neurons) and the precise organization of the spectrin “spacers” within each period is poorly resolved. We have thus begun a project to shed light into this in rodent nerve sections, that is, in situ, using 3D-STORM SR microscopy. We have first established a protocol for the examination of mouse optic and sciatic nerves preparations suitable for them by 3D-STORM. We have preliminary evidence for a model in which spectrin tetramers are arranged in each period at regular and fixed distances irrespective of axonal identity and that scales with axon diameter. We have also evidenced that the localization of a spectrin tetramer in one period is correlated with the position of tetramers in neighboring periods, suggesting a structural constrain for their interaction with actin rings. We believe that describing the MPS at the nanometer scale in situ will provide meaningful insights into its possible functions.