Knockdown of Nurr1 in the rat hippocampus: implications to spatial discrimination learning and memory.

Nurr1 expression is up-regulated in the brain following associative learning experiences, but its relevance to cognitive processes remains unclear. In these studies, rats initially received bilateral hippocampal infusions of control or antisense oligodeoxynucleotides (ODNs) 1 h prior to training in a holeboard spatial discrimination task. Such pre-training infusions of nurr1 antisense ODNs caused a moderate effect in learning the task and also impaired LTM tested 7 d later.

Hippocampal gene expression profiling in spatial discrimination learning.

Learning and long-term memory are thought to involve temporally defined changes in gene expression that lead to the strengthening of synaptic connections in selected brain regions. We used cDNA microarrays to study hippocampal gene expression in animals trained in a spatial discrimination-learning paradigm. Our analysis identified 19 genes that showed statistically significant changes in expression when comparing Nai;ve versus Trained animals.

Induction of secretory pathway components in yeast is associated with increased stability of their mRNA.

The overexpression of certain membrane proteins is accompanied by a striking proliferation of intracellular membranes. One of the best characterized inducers of membrane proliferation is the 180-kD mammalian ribosome receptor (p180), whose expression in yeast results in increases in levels of mRNAs encoding proteins that function in the secretory pathway, and an elevation in the cell's ability to secrete proteins. In this study we demonstrate that neither the unfolded protein response nor increased transcription accounts for membrane proliferation or the observed increase in secretory pathway mRNAs.