EXPERIMENTAL BIOLOGY ANNUAL MEETING April 2010 DNA and Histone Methylation in Learning and Memory J. David Sweatt Dept of Neurobiology McKnight Brain Institute UAB School of Medicine
The Molecular Basis of Memory
Memory at the Cellular Level ES Cell Neuron Differentiation Epigenetic Mechanisms: Histone Acetylation, Methylation, Chromatin Structure DNA Methylation Liver Cell 1 Liver Cell Division Encoded in a pattern of Gene expression Liver Cell 2
Epigenomic Targets Phosphorylation Acetylation Methylation Histones Ubiquitination DNA Methylation PO 4 PO 4 ser 133 ser 133 CREB CREB Basal Transcription Factor IID (TFIID) Complex RNA Polymerase II Target Gene camp Response Element 5 -TGACGTCA-3 TATA Sequence
H3 LYSINE METHYLATION Nowak and Corces (2004) H3 K4 me3 is associated with transcriptional activation. H3 K9 me2 is associated with transcriptional suppression.
Does Associative Learning Cause Hippocampal Histone Methylation? Train Test!@#$ Oh No! Context + Shock Freezing Behavior
Histone Methylation in Area CA1
Is Histone Methylation Necessary for Memory? MLL an H3K4 histone methyltransferase
Fear Conditioning in eed- and mll-deficient Mice
LTP in mll-deficient Mice
Effects of HDACi on Histone Methylation
Histone Methylation in Memory Histone methylation increases with memory formation Different types of memories, e.g. fear conditioning, latent inhibition, and extinction of fear conditioning, are associated with different methylation changes HMT-deficient animals have memory deficits Consistent with the idea of a histone code for memory
Is chemical modification of DNA involved in memory?
DNMT INHIBITORS BLOCK LTP INDUCTION No effect on baseline transmission, PPF, NMDAR
Contextual Fear Conditioning Train Test!@#$ Oh No! Context + Shock Freezing Behavior
DNMT inhibition in hippocampus blocks memory formation in vivo DNMT inhibitor Infusion 1h before Training DNMT inhibitor Training Chamber + Shock 24 h Test Day no shock
DNMT 1/3A Double Conditional Knockout Mice Floxed DNMT1 and DNMT3a Alleles CaMKII driven Cre Forebrain, Postnatal Cre Expression Approximately 80% Loss of DNMT1 and 3A in Adult Guoping Fan, Alcino Silva, UCLA
DNMT 1/3A Double Conditional Knockout Mice Morris Water Maze Contextual Fear Conditioning Guoping Fan, Alcino Silva
DNMT 1/3A Double Conditional Knockout Mice Fan, Silva, Sweatt Laboratories
What is the Cellular Basis for DNMT Control of Long-term Memory Formation?
Stable place cell firing rate maps with repeated spatial exploration
DNA Methyltransferase Inhibition Destabilizes Place Cell Firing
What is the Molecular Basis for DNMT Control of Long-term Memory Formation?
Identified Gene Methylation Targets (so far) BDNF Protein Phosphatase 1 Calcineurin Reelin Arc Zif268
CONCLUSIONS PART 2 DNA methylation is plastic in the adult CNS. Blocking DNMT activity affects memory formation, synaptic plasticity, and place cell stabilization. DNMT activity actively regulates a variety of neuronal gene targets in the adult CNS.
The Molecular Basis of Long-term Memory Epigenetic mechanisms are involved in memory formation Development and long-term memory are homologous molecular processes A universal molecular alphabet for triggering lasting cellular change
Acknowledgements Farah Lubin Tania Roth Courtney Miller Eric Roth Mark Kilgore
Chromatin Structure
Recording Hippocampal Place Cells Behavioral Room/ Experimental Testing Acquisition Room/ Data Processing Camera Commutator Neural data Video Signal Spatial Data: Position, Velocity, Head Direction Acquisition System: Neural Signal Behavioral Apparatus Custom Engineered Micro-drive
HISTONE METHYLATION IN MEMORY What are the upstream regulators?
H3K9me2 is Regulated by ERK -Contextual Fear Conditioning -Area CA1 -Mice p<0.005 p<0.001
HISTONE METHYLATION Histone methylation is downstream of ERK (H3K9me2) Eed and Mll may regulate histone methylation in memory Zif268 and BDNF are downstream of H3K4me3 methylation