Title: Notch signalling becomes transiently attenuated during long-term memory consolidation in adult Wistar rats
Authors: Conboy, Lisa
Seymour, Claire M
Monopoli, Marco P
O'Sullivan, Niamh C
Murphy, Keith J
Regan, Ciaran M # ×
Issue Date: Oct-2007
Publisher: Academic press inc elsevier science
Series Title: Neurobiology of Learning and Memory vol:88 issue:3 pages:342-351
Abstract: Recent evidence has suggested a role for Notch in memory consolidation but the means by which this evolutionarily conserved mechanism serves these plasticity-related processes remains to be established. We have examined a role for this signalling pathway in the hippocampal dentate gyrus of Wistar rats at increasing times following passive avoidance conditioning. Our principal finding is that a transient attenuation of Notch signalling occurs at the 10-12 h post-training time. In this period, extracellular Notch-1 protein fragment exhibited a significant 2- to 3-fold increase but, by contrast, Notch-I mRNA levels were significantly reduced. Moreover, transient inactivation of Notch-1 signalling was further suggested by concomitant reductions in the Notch ligand Jagged-1 and Notch-1 target protein Hes-1 mRNA levels. The C-terminal fragment of PS-1, necessary for gamma-secretase activity, was also significantly reduced at the 12 It post-training time. These events were commensurate with the increase of a Notch immunoreactive fragment of 66 kDa in the nuclear fraction of the dentate gyrus. This fragment, identified with two different Notch-1 antisera, was not the expected NICD polypeptide of similar to I 10 kDa and its accumulation was found to correlate with a significantly reduced expression of the Hes- 1 transcriptional repressor. During the period of reduced Notch activity, a transient increase in soluble P-catenin and GSK-3 beta phosphorylation was observed, indicating a reciprocal activation of the Writ signalling pathway. As down-regulation of Notch signalling promotes differentiation and neurite outgrowth in post-mitotic neurons, it is proposed that this pathway regulates the integration of synapses transiently produced during memory consolidation. (C) 2007 Elsevier Inc. All rights reserved.
ISSN: 1074-7427
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Non-KU Leuven Association publications
× corresponding author
# (joint) last author

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