Cloning and localization of novel stage-specific gene (PKrCb1) of the postnatal rat cerebellum / 대한해부학회지

In rat that is helpless at birth, the cerebellum is in a corresponding state of immaturity, and its histogenesis and morphogenesis mainly occur after birth. The times and sites of origin of the four types of cerebellar local-circuit neurons, as well as their migration routes to specific positions in the cortex, their distinctive patterns of differentiation and growth, and their synaptogenesis, have been well studied. The stage-specific genes in the postnatal rat cerebellum may be related with these kind of neural development in the cerebellum. To clone the genes related with neural development in the postnatal cerebellum, developmentally differentially expressed genes were screened from postnatal rat cerebellum with ordered differential display (ODD) and the developmental expression pattern in the postnatal rat cerebella was investigated with in situ hybridization histochemistry. One novel postnatal stage-specific gene (PKrCb1) was cloned by ODD with 7 cDNA pools (P0, P3, P7, P12, P18, P25, adult rat cerebella). To investigate the developmental expression pattern of this novel gene on the cell level, in situ hybridization histochemistry was performed in the developing and adult rat brain sections. The developmental expression pattern of PKrCb1 in the cerebellum was well matched with spatiotemporal migration pattern of granule cells and it may be suspected that PKrCb1 is related with migration of granule cells from external granular layer to internal granular layer. From the results, it is suggested that the methods used in this experiment will be the powerful methods for the cloning and primary function study of the genes related with cerebellar development.

The effect of kainic acid induced convulsions on the expression of inositol 1,4,5-trisphosphate receptor mRNA in the rat brain / 대한해부학회지

In this study, the effect of systemic administration of kainic acid (KA) on the expression of inositol 1,4,5-trisphosphate receptor mRNA in the rat brain was investigated with in situ hybridization histochemistry. After the injection of KA in a convulsive dose (10 mg/kg i.p.), inositol 1,4,5-trisphosphate receptor mRNA was reduced significantly in dentate gyrus, cerebral cortex, and caudate-putamen and moderately in CA1-CA3 areas of hippocampus and cerebellum. In dentate gyrus, the expression of inositol 1,4,5-trisphosphate receptor mRNA was significantly decreased at 6 h, lowest level at 9 h, after that the expression was gradually recovered and returned to basal level at 72 h after KA injection. However, in the CA1-CA3 areas of the hippocampus, cerebral cortex, and caudate-putamen, the expression of inositol 1,4,5-trisphosphate receptor mRNA was abruptly decreased at 9 h and almost return to basal level at 24 h after KA injection. The significant repression of inositol 1,4,5-trisphosphate receptor mRNA in cerebellum was only found at 9 h after KA injection. But significant change of inositol 1,4,5-trisphosphate receptor mRNA was not found in the brains of rats treated with NMDA receptor blocker, MK-801, followed by KA injection. These observations suggest that the inositol 1,4,5-trisphosphate receptor is one of the genes whose expression can be altered by KA treatment and the NMDA receptor is related with this alternation.

The developmental expression of voltage dependent calcium channel alpha1 subunits (alpha1D, alpha1B, alpha1A, alpha1E) mRNA in the rat brain / 대한해부학회지

Voltage dependent calcium channels (VDCCs) mediate Ca++ influx into cells and are responsible for regulation of a variety of physiological effects. The key functional property of VDCCs are attributed to the calcium-pore forming alpha1 subunit. In this study, distribution pattern of alpha1 subunit (alpha1D, alpha1B, alpha1A, alpha1E) mRNA of VDCCs in developing and adult rat brain was investigated by in situ hybridization histochemistry. In the adult rat brain, each alpha1 subunit mRNA displayed a specific and distinct distribution pattern. alpha1D was highly expressed in the olfactory bulb, dentate gyrus, pituitary gland, pineal gland, hypothalamus, superior colliculus and cerebellum. Relatively low level of alpha1B was expressed throughout the whole brain and strong expression of alpha1A was observed in CA3 area of Ammon's horn, medial geniculate body, inferior colliculus and cerebellum. High level of alpha1E was found in the olfactory bulb, hippocampus, dentate gyrus, medial habenular nucleus and cerebellum. Moreover, alpha1B, alpha1A and alpha1E were expressed only in the nervous system but alpha1D was expressed not only in the nervous system but also in other tissues including liver, heart, lung and skeletal muscle. Generally the expression of alpha1D, alpha1A, and alpha1E subunit was observed from E14 and thereafter the intensity of labeling was gradually increased to P14 and then decreased to the adult level. But the expression of alpha1B subunit was observed from E14 and gradually increased to E20 and P0 and then decresaed. From the differential expressions of VDCC alpha1 subunits in developing and adult rat brain, it is suggested that each type of VDCCs may play a distinct roles in neural and nonneural tissues, and the VDCCs may be related with development of nervous system.

Chromosomal localization and neural distribution of voltage dependent calcium channel alpha1A and alpha1E subunit genes / 대한해부학회지

Fluorescent in situ hybridization using human genomic DNA probes was performed to localize genes encoding the alpha1A and alpha1E of voltage dependent calcium channels (VDCCs) in the human chromosome and the mRNA expression of these two alpha1 subunits of VDCC was demonstrated in the 18 day old embryo (E18) and adult rat brain by in situ hybridization histochemistry. The genes for the VDCC alpha1A and alpha1E were specifically localized on human chromosome 19p13.1 and 1q25, respectively. In 18 days old rat embryos, the mRNAs of the VDCC alpha1A and alpha1E were predominently expressed in the nervous system including brain and spinal cord. In adult rat brain, the expression pattern of each subunit was extremely different. The expression of alpha1A mRNA was strong in the purkinje cells of cerebellum and CA3 area of hippocampus, relatively high level of expression was found in the dentate gyrus, CA1 area of hippocampus, superficial layer of cerebral cortex and olfactory mitral cells. Whereas alpha1E was highly expressed in the dentate gyrus, CA1-3 area of hippocampus, medial habenula nucleus of thalamus and olfactory mitral and internal granule cells and relatively high level of expression was found in the Purkinje cells of cerebellum, cerebral cortex and caudate-putamen. Until now, no neurological disorder has been mapped to 1q25, location of VDCC alpha1E gene. Recently, it has been reported that mutation of VDCC alpha1A gene causes episodic ataxia type 2 (EA-2) and spinocerebellar ataxia 6 (SCA6). These reports comfirm the our experimental results of chromosomal mapping and prominent cerebellar expression of VDCC a1A gene.