title: Genome organization and transcription response to harvest of two metallothionein-like genes in Agaricus bisporus fruiting bodies.
abstract: Metallothioneins are a class of small cysteine-rich proteins that have been associated with increased tolerance to metal and oxidative stresses in animals, plants, and fungi. We investigated a metallothionein-like (mt-like) gene shown previously to be upregulated in fruiting bodies of the fungus Agaricus bisporus in response to post-harvest storage. Analysis of an A. bisporus genomic DNA cosmid library identified two similar mt-like genes (met1 and met2) arranged as a bidirectional gene pair transcribed from the same promoter region. The promoter contained regulatory elements including 9 metal responsive elements and a CAAT box region 220 bp downstream of met1 that showed striking similarity to a feature in Coprinopsis cinerea mt-like gene promoters. Transcriptional analysis showed that both met genes are significantly and rapidly (within 3 hours) upregulated during post-harvest storage and expression is significantly greater in stipe and cap tissues compared with the gills. However, a strong directionality of the promoter was demonstrated, as transcript levels of met1 were at least two orders of magnitude greater than those of met2 in all samples tested.
authors: Department of Bioscience, College of Science, University of Swansea, Singleton Park, Swansea, Wales UK. d.c.eastwood@swansea.ac.uk
authors: Daniel C
authors: DC
authors: Eastwood
authors: Navdeep K
authors: NK
authors: Bains
authors: Janey
authors: J
authors: Henderson
authors: Kerry S
authors: KS
authors: Burton