Labeling of the cDNA probes was performed via standard PCR (5 min
initial denaturation at 94C; denaturation for 40 s at 94C; annealing
for 30 s at 50C; elongation for 60 s at 72C; final extension for 20 min
at 72C) using digoxygenin-labeled nucleotides from Roche (Mannheim),
with GCAGGTACGCAGCTTGGAAAC (forward) and
CCGCTTCGAGTCTGTTGATG (reverse) as specific primers.