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Abstract

Ascomycetes develop four major types of fruiting bodies that share a
common ancestor, and a set of common core genes most likely controls
this process. One way to identify such genes is to search for conserved
expression patterns. We analysed microarray data of Fusarium graminearum
and Sordaria macrospora, identifying 78 genes with similar expression
patterns during fruiting body development. One of these genes was asf1
(anti-silencing function 1), encoding a predicted histone chaperone.
asf1 expression is also upregulated during development in the distantly
related ascomycete Pyronema confluens. To test whether asf1 plays a role
in fungal development, we generated an S. macrospora asf1 deletion
mutant. The mutant is sterile and can be complemented to fertility by
transformation with the wild-type asf1 and its P. confluens homologue.
An ASF1EGFP fusion protein localizes to the nucleus. By tandem-affinity
purification/mass spectrometry as well as yeast two-hybrid analysis, we
identified histones H3 and H4 as ASF1 interaction partners. Several
developmental genes are dependent on asf1 for correct transcriptional
expression. Deletion of the histone chaperone genes rtt106 and cac2 did
not cause any developmental phenotypes. These data indicate that asf1 of
S. macrospora encodes a conserved histone chaperone that is required for
fruiting body development.