The α1 subunit of soluble guanylyl cyclase is expressed prenatally in the rat brain

Abstract

The mRNA encoding the α1 subunit of soluble guanylyl cyclase (α1sGC) was identified in a differential-display screening for genes spatially and temporally regulated during the development of fetal rat brain. The initially isolated fragment of the 3′ untranslated region was used for in situ hybridization and to produce full-length cDNA clones by hybridization screening of cDNA libraries and by RACE (rapid amplification of cDNA ends), respectively. In situ hybridization analysis revealed that α1sGC was absent at embryonic day 12 (E12), but by E14–E15, the forebrain exhibited dense expression in the developing striatum, medial cerebral wall containing the presumptive hippocampus, cerebellar neuroepithelium, and roof plate. Weaker expression was observed in the septum, epithalamus, ventral thalamus, pineal gland and retina. This pattern is largely maintained and refined at E18, with additional expression domains in the olfactory tubercle, nucleus accumbens, zona incerta and neocortex. During early postnatal development, the adult pattern is expressed, as previously reported. The unexpected, early expression of α1sGC, in conjunction with the known absence of its heterodimeric partner, the β subunit of sGC, from the developing rodent brain during fetal ages raises potentially novel functional roles of the α1 subunit during ontogeny, and might imply the existence of an alternative β subunit specific for the prenatal brain.