A Winged-Helix Transcription Factor Foxg1 Induces Expression of Mss4 Gene in Rat Hippocampal Progenitor Cells

Foxg1 (previously named BF1) is a winged-helix transcription factor with restricted expression pattern in the telencephalic neuroepithelium of the neural tube and in the anterior half of the developing optic vesicle. Previous studies have shown that the targeted disruption of the Foxg1 gene leads to hypoplasia of the cerebral hemispheres with severe defect in the structures of the ventral telencephalon. To further investigate the molecular mechanisms by which Foxg1 plays essential roles during brain development, we have adopted a strategy to isolate genes whose expression changes immediately after introduction of Foxg1 in cultured neural precursor cell line, HiB5. Here, we report that seventeen genes were isolated by ordered differential displays that are up-regulated by over-expression of Foxg1, in cultured neuronal precursor cells. By nucleotide sequence comparison to known genes in the GeneBank database, we find that nine of these clones represent novel genes whose DNA sequences have not been reported. The results suggest that these genes are closely related to developmental regulation of Foxg1.

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.

Cloning and characterization of developmentally differentially expressed novel genes from developing rat cerebral cortex / 대한해부학회지

The structural complexity and heterogeneity of cerebral cortex have been obvious since the earliest days of light microscopy. In fact, if there is one word that captures many of the key attributes of cortical structures, it is diversity. Neurodevelopmental approach is the one of the effective ways to understand complicated structures of cerebral cortex. In this experiment, as a first step to clone the genes related with development of cerebral cortex, the developmentally differentially expressed genes were cloned from developing rat brain with ordered differential display PCR(ODD-PCR). Novel genes were screened from these cloned genes by sequencing and sequence analysis with blast search program. The developmental expression patterns of novel genes in the cerebral cortex were investigated with in situ hybridization histochemistry on the developing and adult rat brain sections. Among the forty one developmentally differentially expressed cDNA bands, amplified with InEGA primer and TEAC primer by ODD PCR, twenty novel genes were screened by sequencing and sequence analysis with blast search program. Through the investigation of developmental expression pattern with in situ hybridization histochemistry, specific expression of five novel genes in the developing rat cerebral cortex was identified. 20-E14-2 was highly expressed in the cerebral cortex during the period of neurogenesis. The expression of 20-E20-1, 20-E20-6b, and 20-P0-5 was relatively well matched with neuronal cell migration in the cerebral cortex. And the strong expression of 20-P0-8b was observed in the neuronal cells of cerebral cortex during the period of syanptogenesis. From these results, it may be suspected that the five novel genes play roles in the development of cerebral cortex.

The expression of new rat Ulip mRNA in the developing rat brains / 대한해부학회지

One cDNA was cloned out of developmentally differentially expressed genes in developing rat brains with ordered differential display method (ODD). The expression of cloned cDNA was observed from embryonal day 12 (E12), peaked at postnatal day 7 (P7), decreased to undetectable level at adult. By sequencing and sequence search with GenBank data, it was revealed that cloned cDNA was very similar to mouse Unc-33-like phosphoprotein (Ulip), which is known to be involved in the axonal outgrowth, thus, named as new rat Ulip (nrUlip). In situ hybridization histochemistry of developing rat brains showed that nrUlip mRNA was highly expressed in the area for differentiating neurons and the expression was observed just after neurogenesis in the various brain areas including thalamus, septal area, cerebral cortex, caudate-putamen, hippocampus, cerebellum, and dentate gyrus in the order of neurogenesis. These developmental expression pattern was well matched with the result of ODD. This may justify ODD as one of the best way to clone the genes differen-tially expressed among samples. These results and high sequence homology of nrUlip to mouse Ulip related with axonal outgrowth suggest that nrUlip may be also involved in the outgrowth of axon.