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 
ASF1-EGFP 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.