Chitin synthase genes of Tuber magnatum were sought in order to investigate
the molecular bases of its growth. Primers designed from highly conserved
Chs domains were used to identify a rhs gene portion. A genomic library was
used to obtain the full gene sequence (TMchs4) with an open reading frame
which encodes a predicted protein of 1230 amino acids. The sequence is simi
lar (62%) to the class IV chitin synthase from Neurospora crassa. The putat
ive protein shows hydrophobicity pattern that suggests the presence of seve
ral intramembranous domains and other peculiar features common to the other
rhs of class IV. Northern experiments demonstrated that the gene is expres
sed in ascomata sampled at different maturation steps, These data suggest t
hat ascomata growth requires new chitin deposition, which is based on a chs
gene activation and not only on an enzymatic activity.