CREB in the pond snail Lymnaea stagnalis: cloning, gene expression, and function in identifiable neurons of the central nervous system.
The pond snail Lymnaea stagnalis is an excellent model system in which to study the neuronal and molecular substrates of associative learning and its consolidation into long-term memory. Until now, the presence of cyclic AMP (cAMP)-responsive element binding protein (CREB), which is believed to be a necessary component in the process of a learned behavior that is consolidated into long-term memory, has only been assumed in Lymnaea neurons. We therefore cloned and analyzed the cDNA sequences of homologues of CREB1 and CREB2 and determined the presence of these mRNAs in identifiable neurons of the central nervous system (CNS) of L. stagnalis. The deduced amino acid sequence of Lymnaea CREB1 is homologous to transcriptional activators, mammalian CREB1 and Aplysia CREB1a, in the C-terminal DNA binding (bZIP) and phosphorylation domains, whereas the deduced amino acid sequence of Lymnaea CREB2 is homologous to transcriptional repressors, human CREB2, mouse activating transcription factor-4, and Aplysia CREB2 in the bZIP domain. In situ hybridization revealed that only a relatively few neurons showed strongly positive signals for Lymnaea CREB1 mRNA, whereas all the neurons in the CNS contained Lymnaea CREB2 mRNA. Using one of the neurons (the cerebral giant cell) containing Lymnaea CREB1 mRNA, we showed that the injection of a CRE oligonucleotide inhibited a cAMP-induced, long-lasting synaptic plasticity. We therefore conclude that CREBs are present in Lymnaea neurons and may function as necessary players in behavioral plasticity.
Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan.
Hisayo
H
Sadamoto
Hanae
H
Sato
Suguru
S
Kobayashi
Jun
J
Murakami
Hitoshi
H
Aonuma
Hironori
H
Ando
Yutaka
Y
Fujito
Kaoru
K
Hamano
Masahiko
M
Awaji
Ken
K
Lukowiak
Akihisa
A
Urano
Etsuro
E
Ito
D000595:Amino Acid Sequence / Q000235:genetics; D000818:Animals; D002490:Central Nervous System / Q000187:drug effects / Q000378:metabolism*; D003001:Cloning, Molecular / Q000379:methods*; D000242:Cyclic AMP / Q000494:pharmacology; D017362:Cyclic AMP Response Element-Binding Protein / Q000096:biosynthesis* / Q000235:genetics; D005786:Gene Expression Regulation / Q000502:physiology; D008195:Lymnaea / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*
D017362:Cyclic AMP Response Element-Binding Protein; D000242:Cyclic AMP