A subset of cerebrovascular pericytes originates from mature macrophages in the very early phase of vascular development in CNS.

Pericytes are believed to originate from either mesenchymal or neural crest cells. It has recently been reported that pericytes play important roles in the central nervous system (CNS) by regulating blood-brain barrier homeostasis and blood flow at the capillary level. However, the origin of CNS microvascular pericytes and the mechanism of their recruitment remain unknown.

Ect2, an ortholog of Drosophila Pebble, regulates formation of growth cones in primary cortical neurons.

In collaboration with Marshall Nirenberg, we performed in vivo RNA interference (RNAi) genome-wide screening in Drosophila embryos. Pebble has been shown to be involved in Drosophila neuronal development. We have also reported that depletion of Ect2, a mammalian ortholog of Pebble, induces differentiation in NG108-15 neuronal cells.

Ect2, an ortholog of Drosophila's pebble, negatively regulates neurite outgrowth in neuroblastoma × glioma hybrid NG108-15 cells.

To identify genes required for brain development, we previously performed in vivo RNA interference (RNAi) screening in Drosophila embryos. We identified pebble as a gene that disrupts development of the Drosophila nervous system. Although pebble has been shown to be involved in neuronal development of Drosophila in several screens, the involvement of Ect2, a mammalian ortholog of pebble, in mammalian neuronal development has not been addressed.

Identification and characterization of genes responsible for biosynthesis of kojic acid, an industrially important compound from Aspergillus oryzae.

Kojic acid is produced in large amounts by Aspergillus oryzae as a secondary metabolite and is widely used in the cosmetic industry. Glucose can be converted to kojic acid, perhaps by only a few steps, but no genes for the conversion have thus far been revealed. Using a DNA microarray, gene expression profiles under three pairs of conditions significantly affecting kojic acid production were compared.

Characterization of the palH gene from Aspergillus oryzae.

We disrupted the palH gene, which is known to participate in the ambient pH signal transduction pathway, in Aspergillus oryzae. palH disruption caused significant decreases in pacC expression and alkaline protease activity. Hence we believe that palH plays a very important role in controlling the alkaline protease level in A.

Characterization of copy number mutants of plasmid pSC101.

We have characterized three copy number mutants of the plasmid pSC101. These mutations caused single amino acid substitutions at the 46th, 83rd and 115th codons in the rep gene and an increase in the copy number by 4- to 8-fold. Although the in vivo and in vitro repressor activities of these mutated Rep proteins were quite different from each other, the intracellular concentrations of the proteins were maintained at higher levels than the wild-type protein.