The basidiomycetous mushroom Lentinula edodes white collar-2 homolog PHRB,  a partner of putative blue-light photoreceptor PHRA, binds to a specific site in  the promoter region of the L. edodes tyrosinase gene.
We isolated a cDNA homolog of Neurospora crassa wc-2 from the basidiomycetous mushroom Lentinula edodes and termed it phrB cDNA. The deduced PHRB (313 amino acid residues) contained a PAS domain and a zinc-finger motif. Random binding-site selection analysis of the PHRB produced in Escherichia coli revealed that it bound to a 7-bp sequence with the consensus sequence 5'GATA/TTG/T/AC3'. Electrophoretic mobility-shift assay showed that it also bound to the consensus sequence 5'GATATTC3' in the promoter region of the L. edodes tyrosinase gene (Le.tyr). In vitro GST-pulldown immunoblot analysis disclosed that PHRB interacts with a putative blue-light photoreceptor of L. edodes (PHRA), the homolog of N. crassa WC-1, through the PAS B- and/or PAS C domain of PHRA. The expression of phrB and Le.tyr genes in pre-primordial mycelia of L. edodes is induced by light exposure, suggesting that PHRB can regulate the expression of the Le.tyr gene in a light-dependent manner.
Sano
Hiroaki
H
Department of Life Science, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Midori-ku, Yokohama, Japan. sano.h.aa@m.titech.ac.jp
Kaneko
Shinya
S
Sakamoto
Yuichi
Y
Sato
Toshitsugu
T
Shishido
Kazuo
K