wDAZ is an RNA-binding protein encoded by a region on the Y chromosome impl
icated in infertility, and DAZ-like (Dazl) proteins are master regulators o
f germ line gene expression in all animals. In mice Dazl is only expressed
in germ cells and is necessary for meiosis. A dual approach was taken to un
derstand the RNA-binding specificity of the Dazl protein: (i) traditional S
ELEX and (ii) a novel tri-hybrid screen, Both approaches led to the same co
nclusion, namely that Dazl binds oligo(U) stretches interspersed by G or C
residues. In a directed tri-hybrid assay the strongest interaction was with
the consensus (GUn)n. This motif is found in the 5' UTR of CDC25C whose ho
mologue is thought to be the target of Boule, the Dazl homologue in flies.
CDC25C 5' UTR also interacted specifically with Dazl in vitro. The trihybri
d screen retrieved UTRs of known genes that may be physiological substrates
of Dazl.