Deletion of Prdm8 impairs development of upper-layer neocortical neurons.

Upper-layer (UL) neocortical neurons are the most prominent distinguishing features of the mammalian neocortex compared with those of the avian dorsal cortex and are vastly expanded in primates. However, little is known about the identities of the genes that control the specification of UL neurons. Here, we found that Prdm8, a member of the PR (PRDI-BF1 and RIZ homology) domain protein family, was specifically expressed in the postnatal UL neocortex, particular those in late-born RORß-positive layer IV neurons.

Prdm8 regulates the morphological transition at multipolar phase during neocortical development.

Here, we found that the PR domain protein Prdm8 serves as a key regulator of the length of the multipolar phase by controlling the timing of morphological transition. We used a mouse line with expression of Prdm8-mVenus reporter and found that Prdm8 is predominantly expressed in the middle and upper intermediate zone during both the late and terminal multipolar phases. Prdm8 expression was almost coincident with Unc5D expression, a marker for the late multipolar phase, although the expression of Unc5D was found to be gradually down-regulated to the point at which mVenus expression was gradually up-regulated.

Expression of the mouse PR domain protein Prdm8 in the developing central nervous system.

It was first shown in the PR (PRDI-BF1 and RIZ homology) domain family proteins that the PR domain has homology to the SET (Su(var)3-9, Enhancer-of-zeste and Trithorax) domain, a catalytic domain of the histone lysine methyltransferases. Recently, there are many reports that the PR domain proteins have important roles in development and/or cell differentiation. In this report, we show the expression patterns of one of the mouse PR domain proteins, Prdm8, in the developing central nervous system.

Nutrient-regulated antisense and intragenic RNAs modulate a signal transduction pathway in yeast.

The budding yeast Saccharomyces cerevisiae alters its gene expression profile in response to a change in nutrient availability. The PHO system is a well-studied case in the transcriptional regulation responding to nutritional changes in which a set of genes (PHO genes) is expressed to activate inorganic phosphate (Pi) metabolism for adaptation to Pi starvation. Pi starvation triggers an inhibition of Pho85 kinase, leading to migration of unphosphorylated Pho4 transcriptional activator into the nucleus and enabling expression of PHO genes.

Transcriptional repression by the Pho4 transcription factor controls the timing of SNZ1 expression.

Nutrient-sensing kinases play important roles for the yeast Saccharomyces cerevisiae to adapt to new nutrient conditions when the nutrient status changes. Our previous global gene expression analysis revealed that the Pho85 kinase, one of the yeast nutrient-sensing kinases, is involved in the changes in gene expression profiles when yeast cells undergo a diauxic shift. We also found that the stationary phase-specific genes SNZ1 and SNO1, which share a common promoter, are not properly induced when Pho85 is absent.