| Part IThe vertebrate skeleton is an excellent model for studying fundamental aspects of embryonic development. Cell proliferation, death and movement, and the interpretation of positional information, must be coordinated if an exquisitely patterned limb is to form. Because the limbs are not necessary for embryonic survival, the embryonic limb can be experimentally and molecularly manipulated to define the important cellular and molecular interactions that regulate patterning and skeletal development.The chick embryo has been considered as one of excellent models for studying organgenesis like limb development. In this dissertation, we have established the ectopic expression technique in the embryonic limbs based on electroporation method, and have confirmed the viability of the technique by observing the phenotype of ectopic expression of control gene, such as GFP and N terminal of human IHH cDNA. Then we utilized the electroporation method to implement the preliminary studies of the effect of a newly defined BMPs antagonist, Sostdc1, on the chondrogenesis. We ectopically expressed mouse Sostdc1 cNDA in the chick limb bud at HH stage 25-28, and found that Sostdc1 accelerated bone calcification, down-regulated expression of Msx-1, one of the target genes of BMPs signaling pathway, up-regulated the expression of Runx2, marker gene of terminal hypertrophic chondrocyte maturation and early differentiation of osteoblasts, and down-regulated expression of Sox9, marker gene of chondrocyte condensation, proliferation and differentiation. The data suggest that BMPs signaling could inhibit terminal maturation and calcification of hypertrophic chondrocytes, but it should be further tested whether the molecular interaction was direct or indirect.Part IISchizophrenia is one of the most serious and common type of mental disorders that affects approximately 1% of the population in the world, with characteristics of split of thought, affection and behavior. Genetic components have been considered to play important role in the etiology of schizophrenia, but major common risk loci have not been found yet. Schizophrenia is probably influenced by multiple genes with small or medium risks, and by environment factors as well.In this dissertation, we examined the association relationships of candidate genes Reticulon 4 receptor (RTN4R) and Glycogen synthase kinase-3β(GSK-3β) with schizophrenia in the Han Chinese population on the basis of linkage disequilibrium. RTN4R gene is located in the 22q11 region, which has been considered as one of the hot candidate regions for schizophrenia. Moreover, the gene, encoding a receptor of myelin proteins, is involved in the transduction of neural signals and possibly in the pathophysiology of schizophrenia. In this dissertation, we performed the association analysis of RTN4R gene with schizophrenia by Taqman genotyping technique in the Han Chinese population, with 707 unrelated persons with schizophenia and 689 controls subjects recruited from Shanghai and Jilin for the case-control study, and with 372 unrelated schizophrenia probands and their biological parents from Shanghai for the TDT study. We examined allele and genotype frequencies and haplotype distributions of four SNPs in both family- and nonfamily-based samples, and failed to find any significant association between RTN4R gene and schizophenia in the Han Chinese population. GSK-3βis involved in the WNT, MAPK and PI3K signal transduction cascades. Previous studies have already revealed significant reduction in the protein levels, enzyme activity and mRNA levels of GSK-3βin the postmortem cerebrum of schizophrenics. Relevant association studies have been carried out in a variety of populations, suggesting that GSK-3βmight act as a potential candidate locus for schizophrenia susceptibility. In this dissertation, we performed the association analysis of GSK-3βgene with schizophrenia by Taqman genotyping technique in the Chinese population, with 329 unrelated schizophenic patients, including 118 paranoid subtype subjects, and 288 controls subjects recruited from Shanghai for the case-control study. We found no significant differences of allele, genotype or haplotype frequencies at six SNPs between the schizophrenic patients and controls either in total or when subdivided according to gender. When taking paranoid subtype into consideration, significant differences in allele frequencies at two SNPs were found (P=0.039, 0.027); however, genotype frequency of these two SNPs were not significantly different between two groups. In view of the small sample size of paranoid schizophrenic patients, we considered the significant differences in allele frequencies of the SNPs between paranoid subtype and controls as marginal significance, resulting in no association of GSK-3βgene with susceptibility to schizophrenia in general or in paranoid subtype in the Chinese population. |
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