Detection of p75 mRNA in developing marsupial CNS by cross-hybridization with rat oligonucleotide probes.
We analyzed the distribution of mRNAs encoding the low-affinity neurotrophin receptor (p75) in the CNS of adult and neonatal opossum (Monodelphis demestica) by in situ hybridization with oligodeoxynucleotide probes complementary to cloned rat sequences. During the first 2 postnatal weeks high levels of p75 message were present in the mantle zone throughout the neural tube, in basal forebrain neurons, in motoneurons, and in cerebellar cell layers. Transcript expression decreased with age. In adult CNS only a few cells in the basal forebrain expressed high levels of p75 mRNA. Nerve growth factor upregulated p75 mRNA signals in dorsal root ganglia of cultured 7 day old whole-CNS preparations. Our results indicate the usefulness of rat p75 oligodexynucleotide probes to identify homologous species of transcripts in the CNS of a non-eutherian mammal.