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The initiation and pattern of spread of histone H4 acetylation parallel the order of transcriptional activation of genes in the aflatoxin cluster
Author(s) -
Roze Ludmila V.,
Arthur Anna E.,
Hong SungYong,
Chanda Anindya,
Linz John E.
Publication year - 2007
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2007.05952.x
Subject(s) - acetylation , biology , histone h4 , chromatin immunoprecipitation , histone , aflatoxin , gene cluster , gene , promoter , biochemistry , microbiology and biotechnology , gene expression , food science
Summary The 27 genes involved in aflatoxin biosynthesis are clustered within a 70 kb region in the Aspergillus parasiticus genome. Using chromatin immunoprecipitation, we demonstrated a positive correlation between the initiation and spread of histone H4 acetylation in aflatoxin promoters and the onset of accumulation of aflatoxin proteins and aflatoxin. Histone H4 acetylation in the pks A (encodes an ‘early’ biosynthetic pathway enzyme) promoter peaked at 30 h, prior to the increased acetylation in the omt A and ord A (encode ‘late’ enzymes) promoters detected at 40 h. The specific order in which pks A, ver ‐1 (encodes a ‘middle’ enzyme) and omt A transcripts accumulated in cells paralleled the pattern of spread of histone H4 acetylation. Binding of AflR, a positive regulator of aflatoxin biosynthesis, to the ord A promoter showed a positive correlation with the spread of histone H4 acetylation. The data suggest that the order of genes within the aflatoxin cluster determines the timing and order of transcriptional activation, and that the site of initiation and spread of histone H4 acetylation mediate this process. Our data indicate that the aflatoxin and adjacent sugar utilization clusters are part of a larger ‘regulatory unit’.