Lack of a Retinal Phenotype in a Syne-2/Nesprin-2 Knockout Mouse Model

Language
en
Document Type
Article
Issue Date
2020-01-16
First published
2019-10-11
Issue Year
2019
Authors
Falk, Nathalie
Joachimsthaler, Anneka
Kessler, Kristin
Lux, Uwe Thorsten
Noegel, Angelika Anna
Kremers, Jan
Brandstätter, Johann Helmut
Gießl, Andreas
Editor
Publisher
MDPI
Abstract

Syne-2 (also known as Nesprin-2) is a member of a family of proteins that are found primarily in the outer nuclear membrane, as well as other subcellular compartments. Syne-2 contains a C-terminal KASH transmembrane domain and is part of a protein network that associates the nuclear envelope to the cytoskeleton via the binding to actin filaments. Syne-2 plays a role in nuclear migration, nuclear positioning during retinal development, and in ciliogenesis. In a previous study, we showed a connection between Syne-2 and the multifunctional scaffold protein Pericentrin (Pcnt). The elimination of the interaction of Syne-2 and Pcnt showed defects in nuclear migration and the formation of outer segments during retinal development, as well as disturbances in centrosomal migration at the beginning of ciliogenesis in general. In this study, the Syne-2 KO mouse model Nesprin-2△ABD (Syne-2tm1Ngl, MGI) with special attention to Pcnt and ciliogenesis was analyzed. We show reduced expression of Syne-2 in the retina of the Syne-2 KO mouse but found no significant structural—and only a minor functional—phenotype. For the first time, detailed expression analyses showed an expression of a Syne-2 protein larger than 400 kDa (~750 kDa) in the Syne-2/Nesprin-2 KO mouse. In conclusion, the lack of an overt phenotype in Syne-2/Nesprin-2 KO mice suggests the usage of alternative translational start sites, producing Syne-2 splice variants with an intact Pcnt interaction site. Nevertheless, deletion of the actin-binding site in the Syne-2/Nesprin-2 KO mouse revealed a high variability in scotopic oscillatory potentials assuming a novel function of Syne-2 in synchronizing inner retinal processes.

Journal Title
Cells
Volume
8
Issue
10
Citation
Cells 8.10 (2019): 1238. <https://www.mdpi.com/2073-4409/8/10/1238>