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Requirement of the immediate early gene vesl-1S/homer-1a for fear memory formation.

Inoue N, Nakao H, Migishima R, Hino T, Matsui M, Hayashi F, Nakao K, Manabe T, Aiba A, Inokuchi K - Mol Brain (2009)

Bottom Line: The short form of Vesl (Vesl-1S) is an alternatively spliced isoform of the vesl-1 gene, which also encodes the long form of the Vesl protein (Vesl-1L).Vesl-1L is a postsynaptic scaffolding protein that binds to and modulates the metabotropic glutamate receptor 1/5 (mGluR1/5), the IP3 receptor, and the ryanodine receptor.These results indicate that the short form of the Vesl family of proteins plays a role in multiple steps of long-term, but not short-term, fear memory formation.

View Article: PubMed Central - HTML - PubMed

Affiliation: Mitsubishi Kagaku Institute of Life Sciences, MITILS, 11 Minamiooya, Machida, Tokyo 194-8511, Japan. inouenok@yahoo.co.jp

ABSTRACT

Background: The formation of long-term memory (LTM) and the late phase of long-term potentiation (L-LTP) depend on macromolecule synthesis, translation, and transcription in neurons. vesl-1S (VASP/Ena-related gene upregulated during seizure and LTP, also known as homer-1a) is an LTP-induced immediate early gene. The short form of Vesl (Vesl-1S) is an alternatively spliced isoform of the vesl-1 gene, which also encodes the long form of the Vesl protein (Vesl-1L). Vesl-1L is a postsynaptic scaffolding protein that binds to and modulates the metabotropic glutamate receptor 1/5 (mGluR1/5), the IP3 receptor, and the ryanodine receptor. Vesl-1 mutant mice show abnormal behavior, which includes anxiety- and depression-related behaviors, and an increase in cocaine-induced locomotion; however, the function of the short form of Vesl in behavior is poorly understood because of the lack of short-form-specific knockout mice.

Results: In this study, we generated short-form-specific gene targeting (KO) mice by knocking in part of vesl-1L/homer-1c cDNA. Homozygous KO mice exhibited normal spine number and morphology. Using the contextual fear conditioning test, we demonstrated that memory acquisition and short-term memory were normal in homozygous KO mice. In contrast, these mice showed impairment in fear memory consolidation. Furthermore, the process from recent to remote memory was affected in homozygous KO mice. Interestingly, reactivation of previously consolidated fear memory attenuated the conditioning-induced freezing response in homozygous KO mice, which suggests that the short form plays a role in fear memory reconsolidation. General activity, emotional performance, and sensitivity to electrofootshock were normal in homozygous KO mice.

Conclusion: These results indicate that the short form of the Vesl family of proteins plays a role in multiple steps of long-term, but not short-term, fear memory formation.

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Immunohistochemistry using a Vesl-1L-specific antibody. Mice were subjected to MECS and brains were dissected 5 h later. A sagital section is shown. IC, inferior colliculus; OB, olfactory bulb; S, subiculum; Cx, neocortex; BS, brain stem; Cer, cerebellum.
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Figure 3: Immunohistochemistry using a Vesl-1L-specific antibody. Mice were subjected to MECS and brains were dissected 5 h later. A sagital section is shown. IC, inferior colliculus; OB, olfactory bulb; S, subiculum; Cx, neocortex; BS, brain stem; Cer, cerebellum.

Mentions: Neural activity-dependent regulation of alternative RNA splicing is mediated by activity-dependent selection of poly(A) sites that are located at the 3' end of exons 5 and 6 [23,24]. Because genomic DNA of KO mice lacked these poly(A) sites and the expression of knocked-in vesl-1L mRNA was directed by the endogenous vesl-1 promoter, we wondered whether the level of Vesl-1L protein was augmented in a neural activity-dependent manner. Western blot analysis revealed that the level of Vesl-1L protein did not increase after the application of a maximum electroconvulsive shock (MECS) in the hippocampus of KO mice and was comparable to that of wild type mice in the condition where the level of Vesl-1S protein was increased (Figure 2c). Furthermore, the region specificity of the Vesl-1L protein was conserved between wild-type and KO mice (Figure 3). Regions that expressed Vesl-1L protein at high levels included the cortex, the CA1, the CA3, and the dentate gyrus of the hippocampus, the subiculum, and the inferior colliculus. Low Vesl-1 expression levels were detected in the CA2 area of the hippocampus, the olfactory bulb, the brain stem, and the cerebellum; thus, we successfully generated short-form-specific KO mice in which the expression of Vesl-1L protein was unaltered.


Requirement of the immediate early gene vesl-1S/homer-1a for fear memory formation.

Inoue N, Nakao H, Migishima R, Hino T, Matsui M, Hayashi F, Nakao K, Manabe T, Aiba A, Inokuchi K - Mol Brain (2009)

Immunohistochemistry using a Vesl-1L-specific antibody. Mice were subjected to MECS and brains were dissected 5 h later. A sagital section is shown. IC, inferior colliculus; OB, olfactory bulb; S, subiculum; Cx, neocortex; BS, brain stem; Cer, cerebellum.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2663561&req=5

Figure 3: Immunohistochemistry using a Vesl-1L-specific antibody. Mice were subjected to MECS and brains were dissected 5 h later. A sagital section is shown. IC, inferior colliculus; OB, olfactory bulb; S, subiculum; Cx, neocortex; BS, brain stem; Cer, cerebellum.
Mentions: Neural activity-dependent regulation of alternative RNA splicing is mediated by activity-dependent selection of poly(A) sites that are located at the 3' end of exons 5 and 6 [23,24]. Because genomic DNA of KO mice lacked these poly(A) sites and the expression of knocked-in vesl-1L mRNA was directed by the endogenous vesl-1 promoter, we wondered whether the level of Vesl-1L protein was augmented in a neural activity-dependent manner. Western blot analysis revealed that the level of Vesl-1L protein did not increase after the application of a maximum electroconvulsive shock (MECS) in the hippocampus of KO mice and was comparable to that of wild type mice in the condition where the level of Vesl-1S protein was increased (Figure 2c). Furthermore, the region specificity of the Vesl-1L protein was conserved between wild-type and KO mice (Figure 3). Regions that expressed Vesl-1L protein at high levels included the cortex, the CA1, the CA3, and the dentate gyrus of the hippocampus, the subiculum, and the inferior colliculus. Low Vesl-1 expression levels were detected in the CA2 area of the hippocampus, the olfactory bulb, the brain stem, and the cerebellum; thus, we successfully generated short-form-specific KO mice in which the expression of Vesl-1L protein was unaltered.

Bottom Line: The short form of Vesl (Vesl-1S) is an alternatively spliced isoform of the vesl-1 gene, which also encodes the long form of the Vesl protein (Vesl-1L).Vesl-1L is a postsynaptic scaffolding protein that binds to and modulates the metabotropic glutamate receptor 1/5 (mGluR1/5), the IP3 receptor, and the ryanodine receptor.These results indicate that the short form of the Vesl family of proteins plays a role in multiple steps of long-term, but not short-term, fear memory formation.

View Article: PubMed Central - HTML - PubMed

Affiliation: Mitsubishi Kagaku Institute of Life Sciences, MITILS, 11 Minamiooya, Machida, Tokyo 194-8511, Japan. inouenok@yahoo.co.jp

ABSTRACT

Background: The formation of long-term memory (LTM) and the late phase of long-term potentiation (L-LTP) depend on macromolecule synthesis, translation, and transcription in neurons. vesl-1S (VASP/Ena-related gene upregulated during seizure and LTP, also known as homer-1a) is an LTP-induced immediate early gene. The short form of Vesl (Vesl-1S) is an alternatively spliced isoform of the vesl-1 gene, which also encodes the long form of the Vesl protein (Vesl-1L). Vesl-1L is a postsynaptic scaffolding protein that binds to and modulates the metabotropic glutamate receptor 1/5 (mGluR1/5), the IP3 receptor, and the ryanodine receptor. Vesl-1 mutant mice show abnormal behavior, which includes anxiety- and depression-related behaviors, and an increase in cocaine-induced locomotion; however, the function of the short form of Vesl in behavior is poorly understood because of the lack of short-form-specific knockout mice.

Results: In this study, we generated short-form-specific gene targeting (KO) mice by knocking in part of vesl-1L/homer-1c cDNA. Homozygous KO mice exhibited normal spine number and morphology. Using the contextual fear conditioning test, we demonstrated that memory acquisition and short-term memory were normal in homozygous KO mice. In contrast, these mice showed impairment in fear memory consolidation. Furthermore, the process from recent to remote memory was affected in homozygous KO mice. Interestingly, reactivation of previously consolidated fear memory attenuated the conditioning-induced freezing response in homozygous KO mice, which suggests that the short form plays a role in fear memory reconsolidation. General activity, emotional performance, and sensitivity to electrofootshock were normal in homozygous KO mice.

Conclusion: These results indicate that the short form of the Vesl family of proteins plays a role in multiple steps of long-term, but not short-term, fear memory formation.

Show MeSH
Related in: MedlinePlus