Journal of Neuroscience, Vol 6, 522-530, Copyright © 1986 by Society for Neuroscience
The brain-specific gene 1B236 is expressed postnatally in the developing rat brain
D Lenoir, E Battenberg, M Kiel, FE Bloom and RJ Milner
The rat brain-specific polypeptide 1B236 was previously characterized by
molecular cloning and nucleotide sequence determination of its mRNA. It has
been shown to exist in rat brain in discrete neuronal circuits, primarily
as a 100,000 Da glycoprotein. We now have determined the time course of
expression of 1B236 mRNA and protein in rat brain during fetal and
postnatal development, detecting 1B236 mRNA by RNA blotting and assaying
1B236 protein by electroblotting and radioimmunoassay with antibodies
against synthetic peptides. By both indices, expression of the 1B236 gene
products is found to be a relatively late event in neuronal development.
1B236 mRNA is first detectable in extracts of whole rat brain at Postnatal
Day 5 (PD 5) and increases to a maximum concentration at PD 25. In extracts
of dissected brain regions, 1B236 mRNA is first detectable at PD 5 in
hindbrain and cerebellum, at PD 9 in midbrain/diencephalon, but not until
PD 13 in telencephalon. The appearance of 1B236 protein follows a very
similar time course to that of its mRNA in both whole brain and dissected
brain regions, suggesting that the expression of the protein during
development is regulated largely by transcription of its mRNA. The pattern
of 1B236 expression was confirmed by immunocytochemical localization of
1B236 protein: Immunoreactive material can be detected first in spinal cord
at PD 3-PD 5 and then appears in progressively more rostral brain regions
in increasingly older animals. Several brain regions, however, that do not
contain 1B236 immunoreactivity in the adult, such as optic nerve and
somatic efferent cranial nerve nuclei, show transient expression of 1B236
during postnatal development.(ABSTRACT TRUNCATED AT 250 WORDS)