A combined in situ hybridization and RT-PCR method to detect spatial and temporal patterns of Noggin gene expression in embryonic and postnatal rat hippocampus.

Recent studies indicate that Noggin not only plays an important role in the early development of the nervous system, but may also plays a role in postnatal central nervous system (CNS) development. In this study, we examined the relative levels and localization of Noggin mRNA in the hippocampus of rats of different developmental stages with reverse transcriptase-polymerase chain reaction (RT-PCR) and in situ hybridization. RT-PCR showed that the peak level of expression of Noggin mRNA was observed at embryonic day 13 (E13), subsequently gradually declined at 1-3 months (P1-3M) postnatal, and was detected only at a low level at P18M. In situ hybridization revealed that at embryonic stages, Noggin mRNA was localized throughout all hippocampal regions, whereas at early postnatal ages, Noggin mRNA was primarily localized in the anterior subiculum. At later postnatal ages, Noggin mRNA expression was obviously observed in the dentate gyrus and in the CA1-CA3 pyramidal cell layers. Taken together, our results demonstrate that Noggin is expressed in embryonic and postnatal hippocampus, and that the temporal and spatial patterns of its expression is developmentally regulated.