凋亡相关基因的整合分析及基因表达芯片的制备

利用IPI和GenBank,收集了与凋亡相关的5 333条基因序列,用一定的标准,整合筛选得到1 384个凋亡相关的基因．通过亚细胞定位、组织表达差异显著性分析、自然正义/反义RNA对预测、基因簇在pathway上的定位、蛋白质/蛋白质相互作用等方面的分析发现,一些基因只在一个组织里显著差异表达,一些基因存在自然正义/反义RNA对现象,一些基因簇同时位于多条pathway等重要信息．同时,制作了一张凋亡相关基因的寡核苷酸芯片,并且对于一对NAIF1表达质粒转染前后的HeLa样品,通过该芯片的筛选,得到24个差异表达的基因．发现NAIF1过表达诱导的细胞凋亡,伴随了PAX2、PDCD8、PDCD10、DFFA、CASP7等基因表达的显著变化,同时还发现,U58668,该mRNA没有任何基因或蛋白质的注释信息,当camptothecin诱导U937细胞系凋亡时上调,在这里的NAIF1过表达诱导的HeLa细胞系中也上调(上述数据结果见http://gpcrome.cbi.pku.edu.cn:2005/chip)．     

Detection of SNPs in Porcine Haptoglobin and Apolipoprotein Genes

To find differentially expressed protein spots using two-dimensional electrophoresis proteomic analysis, we took blood serum samples from 40 purebred Yorkshire pigs at 12, 18, 24, and 30 weeks. Each growth stage contained 10 male pigs having half-sib pedigrees. With the pooled serum samples, two interesting spots, differentially expressed in the growth stages, were identified using MALDI-TOF-TOF MS/MS analysis as haptoglobin alpha 1S (Hp) and apolipoprotein A-IV (APOA4) gene products. The Hp was down-regulated from 12 to 30 weeks, and APOA4 was not expressed much before 18 weeks but was highly expressed in the late growth stages. There may be an inverse relationship between the Hp and APOA4 genes. Four segments for the Hp and APOA4 genes were successfully amplified with sizes around 500 bp. The porcine Hp and APOA4 genes were screened in the 40 purebred Yorkshire pigs and a random cross population (90 pigs), resulting in the location of 6 single nucleotide polymorphisms (SNPs) in the coding regions. The mutations resulted in amino acid changes in segments of Hp627, Hp742, and APOA41203. Further investigation of the function of the Hp and APOA4 genes with SNPs will be necessary to understand fully the different expression profiles and association studies.     

Suppression subtractive hybridization identifies differentially expressed genes in Brassica napus chlorophyll-reduced mutant

Suppressive subtraction hybridization (SSH) was used to identify differentially expressed genes caused by a chlorophyll-reduced mutation in B. napus. The cDNA fragments, derived from SSH positive subtractive library (tester: normal wild type, driver: mutant) were cloned into pMD18-T vector. Two hundred SSH cDNA clones were screened by dot blot array, and 151 clones were identified as differentially expressed cDNA fragments in Cr3529 line. Thirty-six positive clones which showed marked expression differences were selected and sequenced. After redundant cDNAs were removed, 33 differentially expressed unique cDNA section clones were obtained. Among the 33 clones, two clones possess different parts of the cDNA sequence of the same gene coding geranylgeranyl reductase, four clones belong to unknown proteins, and the rest share homology to genes of diverse class. Sequence analysis showed that at least 12 genes were discovered to be related to the photosynthesis, seven of them coded the proteins which belong to the subunit of photosystem 2. RNA gel blot analysis showed that compared with 3529, the gene expression of the chlorophyll a/b-binding protein Lhcb2 in photosystem 2 declined markedly in the cotyledons and seedling leaves of Cr3529, indicating that the reduced light-harvesting complex 2 accumulation in thylakoid membrane of Cr3529 was due to the decrease of the related gene mRNA level for translation.