猪脂肪前体细胞分化过程中聚脂相关基因的表达模式

本实验采用胶原酶消化法分离猪皮下脂肪前体细胞,用含850 nmol/L 胰岛素和50 nmol/L地塞米松的诱导培养液进行诱导,采用油红O提取法测定了细胞中的甘油三酯含量,同时采用实时定量RT-PCR方法检测了细胞分化过程中聚脂相关基因的表达.结果显示:转录因子PPAR γ和C/EBP β在诱导后12 h即迅速表达,SREBP-1 mRNA表达水平在诱导后12 h出现显著下调,随后逐渐升高,96 h达到最高水平;脂肪合成相关酶基因GPDH、FAS、ACC和LPL呈现出与SREBP-1相似的表达模式;脂肪酸转运相关基因aP2、FAT、FATP1与VLDLR的表达量随着细胞分化过程的延长而不断增加,并且与细胞内甘油三酯的含量变化高度相关.本实验结果表明,PPAR γ、C/EBP β和SREBP-1可能是调控猪脂肪前体细胞分化的关键转录因子.猪皮下脂肪组织在聚脂过程中,在分化早期可能以脂肪细胞自身合成脂肪酸为主,而后期则主要依赖细胞外脂肪酸的跨膜转运.这些结果可能有助于揭示脂肪细胞的分化调控规律.     

Chromosomal assignments for porcine genes encoding enzymes in hepatic metabolic pathways

Increasing the number of mapped genes will facilitate (1) the identification of potential candidate genes for a trait of interest within quantitative trait loci regions and (2) comparative mapping. The metabolic activities of the liver are essential for providing fuel to peripheral organs, for regulation of amino acid, carbohydrate and lipid metabolism and for homoeostasis of vitamins, minerals and electrolytes. We aimed to identify and map genes coding for enzymes active in the liver by somatic cell genetics in order to contribute to the improvement of the porcine gene map. We mapped 28 genes of hepatic metabolic pathways including six genes whose locations could be confirmed and 22 new assignments. Localization information in human was available for all but one gene. In total 24 genes were assigned to in the expected chromosomal regions on the basis of the currently available information on the comparative human and pig map while for four genes our results suggest a new correspondence or extended regions of conservation between porcine and human chromosomes.     

Chromosomal localization of three human genes encoding bone morphogenetic protein receptors

Bone morphogenetic proteins (BMPs) are members of the TGF-β superfamily that play a pivotal role in bone formation during embryogenesis and fracture repair. BMP signaling occurs via hetero-oligomeric serine/threonine kinase complexes of BMP type I (BMPR-IA or BMPR-IB) and type II receptors (BMPR-II). BMPR-IA and IB are closely related receptors, with sequence differences conserved between different species, suggesting that they serve distinct functions. Here we report the cDNA cloning of human BMPR1B and the chromosomal localization of all three BMPR genes. Using somatic cell hybrid and FISH analyses, the BMPR1A, BMPR1B, and BMPR2 genes were assigned to 10q23, 4q22-24, and 2q33-34, respectively. A processed BMPR1A pseudogene was mapped to 6q23. Received: 17 February 1997 / Accepted: 15 October 1998     

Multidimensional analysis and functional assignment of DNA-microarray transcription profiles of genes involved in adipogenesis

The results of two independent DNA-microarray experiments concerning adipogenesis in the murine preadipocyte 3T3-L1 cell line, which covered the first two days after the induction of differentiation, were analyzed using the multidimensional scaling (MDS) method. In both data arrays, the first three scaling components accounted for 73.5–73.8% of the total dispersion. This result implies that both arrays of the gene expression profiles are in fact three-dimensional and each component reflects a definite principal process involved in one of the three early stages of adipogenesis: (i) determination of the fibroblast-like stem cells, (ii) clonal expansion of adipoblasts, and (iii) preadipocyte conversion into a mature adipocyte phenotype. Each profile of the gene expression is characterized by coefficients of correlation with the first three scaling components. The functional annotation in terms of the Gene Ontology database profiles (sorted according to the correlations with each component) generally corresponds to a regular change of elementary biological processes during the three early stages of adipogenesis. Analysis of correlations with the principal scaling components for the genes previously classified as subject to differential expression in the course of adipogenesis in mice suggests a complicated role of these genes in early adipogenesis (in some cases, described in the literature). The MDS analysis of the gene expression profiles and the analysis of correlations between these profiles and the main scaling components provides a deeper insight into the fine role of these genes and makes possible the search for new biomarkers of various differentiation stages.

     

罗格列酮对猪脂肪前体细胞分化过程中聚脂相关基因表达模式的影响

为了解罗格列酮对猪脂肪前体细胞诱导分化过程的影响, 利用胶原酶消化法分离猪皮下脂肪前体细胞, 采用含50 nmol/L胰岛素、100 nmol/L地塞米松及0.25 mmol/L 3-异丁基-1-甲基黄嘌呤的分化培养液Ⅰ(对照组)和在分化培养液Ⅰ中添加100 nmol/L罗格列酮的分化培养液Ⅱ(实验组)两种诱导分化方法对脂肪前体细胞进行诱导分化, 借助实时定量RT-PCR方法检测了细胞分化过程中聚脂相关基因的表达。结果显示: 罗格列酮对PPARγ、C/EBPα、FABP4、FASN和GPAT基因的表达有显著的上调作用, 而对PPARα有一定的下调作用。试验组中PPARα、PPARγ、C/EBPα、FABP4、FASN和GPAT等基因分别于48 h、48 h、48 h、108 h、60 h和24 h达到表达高峰, 此时的表达量分别是诱导前的1.7、48、3.3、487.5、5.8和3.6倍, GPAT同PPARα和FASN基因表达量间均达到显著相关(P<0.05); 而对照组中PPARα、PPARγ、C/EBPα、FABP4、FASN和GPAT等基因分别于84 h、96 h、48 h、96 h、36 h和36 h达到表达高峰, 此时的表达量分别是诱导前的2.1、11、1.6、216.5、3.5和2.8倍, GPAT同PPARα和FASN基因表达量间均达到极显著相关(P<0.01)。本实验结果表明: 罗格列酮不仅可以极大的促进PPARγ和C/EBPα基因的表达, 还能让其协同达到表达高峰; PPARγ和C/EBPα可能是调控猪脂肪前体细胞分化的关键转录因子; 在脂肪形成过程中, 甘油脂类的生物合成可能发生较早, 同时PPARα可能主要参与甘油脂类生物合成的调控。     

Chromosomal localization of genes involved in biosynthesis,metabolism or transport of cholesterol in the rat

Several genes involved in biosynthesis, transport or metabolism of cholesterol have been localized on rat chromosomes by using a radiation hybrid (RH) panel. The genes, coding for squalene epoxidase (Sqle), mevalonate kinase (Mvk), and farnesyl diphosphate farnesyl transferase 1 (Fdft1) which are involved in cholesterol biosynthesis, have been mapped on chromosome 7, 12, and 15, respectively. The genes coding for phospholipid transfer protein (Pltp), sterol carrier protein-2 (Scp2), ATP binding cassette reporter A7 (Abca7), scavenger receptor class B, type 1 (Cd36l1), steroidogenic acute regulatory protein (Star), and lecithin:cholesterol acyl transferase (Lcat), which are involved in the transfer and/or metabolism of cholesterol, have been mapped on chromosome 3, 5, 7, 12, 16, and 19, respectively. Each of the genes Scp2, Sqle and Fdft1 maps close to a QTL for serum total cholesterol in rat, suggesting that these three genes might represent candidate genes for the previously mapped QTLs.     

Chromosomal localization of HSP70 genes in cattle

Five genomic clones representing three HSP70 genes of cattle were biotin labeled and independently hybridized to cattle chromosomes. Fluorescence in situ hybridization localized HSP70-2 to Chromosome (Chr) 23 band 22 (the BoLA region), HSP70-3 to Chr 10 band 34, and HSP70-4 to Chr 3 band 13. Since HSP70-1, a fourth HSP70 gene, is tightly linked with HSP70-2 and the BOLA@, HSP70-1 was also localized to Chr 23 band 22. The localization of HSP70-4 is the first assignment of a cattle U6 marker; thus, this entire syntenic group is tentatively placed in cattle Chr 3.