TY - JOUR
T1 - Requirement of new protein synthesis of a transcription factor for memory consolidation
T2 - Paradoxical changes in mRNA and protein levels of C/EBP
AU - Hatakeyama, Dai
AU - Sadamoto, Hisayo
AU - Watanabe, Takayuki
AU - Wagatsuma, Akiko
AU - Kobayashi, Suguru
AU - Fujito, Yutaka
AU - Yamashita, Masakane
AU - Sakakibara, Manabu
AU - Kemenes, György
AU - Ito, Etsuro
N1 - Funding Information:
We show here that CTA in L. stagnalis is associated with a rapid synthesis and phosphorylation of LymC/EBP and a rapid breakdown of LymC/EBP mRNA in the neural network involved in feeding, and in particular, in a pair of identified motoneurons controlling foregut motility. In situ hybridization and immunohistochemistry revealed the existence of LymC/EBP mRNA and protein in the paired B2 motoneurons in the buccal ganglia ( Figures 2 and 3 ). Previous reports showed that two homologs of C/EBP, C/EBPβ and C/EBPδ, were co-localized with the phosphorylated form of CREB in rat hippocampus neurons and they were induced at discrete times after learning. 29 Although we did not examine the CRE element upstream of LymC/EBP in the present study, the expression of LymC/EBP is likely to be regulated by Lymnaea CREB. 32–35 This conclusion is supported by the data from Aplysia , 24 Helix 36 and mammals. 37
PY - 2006/2/24
Y1 - 2006/2/24
N2 - Some specific transcription factors are essential for memory consolidation across species. However, it is still unclear whether only the activation of constitutively expressed forms of these conserved transcription factors is involved in memory consolidation or their de novo synthesis also occurs after learning. This question has remained unanswered partly because of the lack of an efficient method for the determination of copy numbers of particular mRNAs in single neurons, which allows the detection of new transcription at the cellular level. Here we applied a newly developed protocol of single-cell quantitative real-time polymerase chain reaction (qRT-PCR) to single neurons playing an important role in associative learning. Specifically, we examined the changes in the mRNA and protein expression levels of a highly conserved transcription factor, CCAAT/enhancer binding protein (C/EBP), in the paired B2 motoneurons of the pond snail Lymnaea stagnalis. These buccal neurons are involved in the motor control of feeding behavior, with a potentially important role in conditioned taste aversion (CTA). Single-cell qRT-PCR revealed a significant decrease in LymC/EBP mRNA copy numbers in the B2 motoneurons during memory consolidation after CTA training. By contrast, isoelectric focusing and immunoblotting of extracts of the buccal ganglia showed that translation and phosphorylation levels of LymC/EBP significantly increased during memory consolidation. The C/EBP-like immunoreactivity in the B2 motoneurons, which are the major immunopositive component in the buccal ganglia, also significantly increased during memory consolidation, suggesting that the main source of increase in the level of protein in the buccal ganglia are the B2 motoneurons. Thus, early memory consolidation after CTA learning in L. stagnalis involves both the rapid synthesis and phosphorylation of LymC/EBP as well as the rapid breakdown of LymC/EBP mRNA in the neural network controlling feeding, suggesting that all of these processes play a role in the function of C/EBP in memory consolidation.
AB - Some specific transcription factors are essential for memory consolidation across species. However, it is still unclear whether only the activation of constitutively expressed forms of these conserved transcription factors is involved in memory consolidation or their de novo synthesis also occurs after learning. This question has remained unanswered partly because of the lack of an efficient method for the determination of copy numbers of particular mRNAs in single neurons, which allows the detection of new transcription at the cellular level. Here we applied a newly developed protocol of single-cell quantitative real-time polymerase chain reaction (qRT-PCR) to single neurons playing an important role in associative learning. Specifically, we examined the changes in the mRNA and protein expression levels of a highly conserved transcription factor, CCAAT/enhancer binding protein (C/EBP), in the paired B2 motoneurons of the pond snail Lymnaea stagnalis. These buccal neurons are involved in the motor control of feeding behavior, with a potentially important role in conditioned taste aversion (CTA). Single-cell qRT-PCR revealed a significant decrease in LymC/EBP mRNA copy numbers in the B2 motoneurons during memory consolidation after CTA training. By contrast, isoelectric focusing and immunoblotting of extracts of the buccal ganglia showed that translation and phosphorylation levels of LymC/EBP significantly increased during memory consolidation. The C/EBP-like immunoreactivity in the B2 motoneurons, which are the major immunopositive component in the buccal ganglia, also significantly increased during memory consolidation, suggesting that the main source of increase in the level of protein in the buccal ganglia are the B2 motoneurons. Thus, early memory consolidation after CTA learning in L. stagnalis involves both the rapid synthesis and phosphorylation of LymC/EBP as well as the rapid breakdown of LymC/EBP mRNA in the neural network controlling feeding, suggesting that all of these processes play a role in the function of C/EBP in memory consolidation.
KW - Conditioned taste aversion
KW - Lymnaea
KW - Single-cell qRT-PCR
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U2 - 10.1016/j.jmb.2005.12.009
DO - 10.1016/j.jmb.2005.12.009
M3 - Article
C2 - 16403525
AN - SCOPUS:31344457448
VL - 356
SP - 569
EP - 577
JO - Journal of Molecular Biology
JF - Journal of Molecular Biology
SN - 0022-2836
IS - 3
ER -