Class I histone deacetylase (HDAC) inhibitors are believed to have positive 
effects on neurite outgrowth, synaptic plasticity, and neurogenesis in adult 
brain. However, the downstream molecular targets of class I HDAC inhibitors in 
neurons are not clear. Although class I HDAC inhibitors are thought to broadly 
promote transcription of many neuronal genes through enhancement of histone 
acetylation, the affected gene set may include unidentified genes that are 
essential for neuronal survival and function. To identify novel genes that are 
targets of class I HDAC inhibitors, we used a microarray to screen transcripts 
from neuronal cultures and evaluated changes in protein and mRNA expression 
following treatment with four HDAC inhibitors. We identified tescalcin (Tesc) as 
the most strongly up-regulated gene following treatment with class I HDAC 
inhibitors in neurons. Moreover, hippocampal neurons overexpressing TESC showed 
a greater than 5-fold increase in the total length of neurites and number of 
branch points compared with controls. These findings highlight a potentially 
important role for TESC in mediating the neuroprotective effect of class I HDAC 
inhibitors. TESC may also be involved in the development of brain and 
neurodegenerative diseases through epigenetic mechanisms.