Molecular cloning of a neuron-specific transcript and its regulation during normal and aberrant cerebellar development.
PEP-19 is a brain-specific polypeptide whose levels increase dramatically during the late maturation of the rodent nervous system. By using immunocytochemistry, PEP-19 is shown to be localized to several regions of the central nervous system, notably cerebellum, thalamus caudate putamen, and olfactory bulb. We have isolated a 0.5-kilobase cDNA clone that encodes the entire PEP-19 protein sequence, making this one of the smallest primary transcripts and translation products ever identified in eukaryotes. The cDNA was used to investigate the developmental expression of PEP-19 in rodent brain. PEP-19 mRNA rises from low levels at embryonic day 17 of gestation in the rat to a plateau value by day 18 postpartum. This mirrored the levels of the protein determined by radioimmunoassay. Since the rise coincided with the formation of synaptic contacts onto Purkinje cells (a major site of PEP-19 expression), the hypothesis was tested that the activity and/or presence of afferent input modulated PEP-19 expression. Parallel fiber innervation was disrupted either by killing granule cells with the cytostatic agent methylazoxymethanol or by examining PEP-19 levels in cerebellar granuloprival mutant mice (reeler and weaver). The influence of climbing fiber input was assessed by either eliminating them with 3-acetylpyridine or stimulating them with harmaline in both neonatal and mature rats. None of the above altered PEP-19 gene expression in cerebellum, leading us to propose that the signals triggering the PEP-19 gene do not emanate from granule cells or neurons in the olivary nucleus. However, preliminary evidence suggests that PEP-19 is under posttranscriptional regulation.
Sangameswaran
L
L
Department of Neurosciences, Roche Institute of Molecular Biology, Roche Research Center, Nutley, NJ 07110.
Hempstead
J
J
Morgan
J I
JI
D000375:Aging; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D001921:Brain / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D002148:Calmodulin-Binding Proteins; D002526:Cerebellar Diseases / Q000139:chemically induced / Q000378:metabolism*; D002531:Cerebellum / Q000378:metabolism*; D003001:Cloning, Molecular; D005786:Gene Expression Regulation; D005796:Genes; D006246:Harmaline / Q000494:pharmacology; D008297:Male; D008746:Methylazoxymethanol Acetate / Q000633:toxicity; D051379:Mice; D008817:Mice, Mutant Strains; D008969:Molecular Sequence Data; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000235:genetics*; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values; D014158:Transcription, Genetic / Q000187:drug effects
D002148:Calmodulin-Binding Proteins; D009419:Nerve Tissue Proteins; C489091:Pcp4 protein, mouse; C489090:Pcp4 protein, rat; D011725:Pyridines; D012333:RNA, Messenger; C010835:3-acetylpyridine; D008746:Methylazoxymethanol Acetate; D006246:Harmaline