细胞衰老相关基因的探索

细胞衰老与个体衰老、机体自我保护及细胞癌变等多种重要生理、病理现象密切相关,其机制研究可望应用于癌症治疗.简述了近年有关哺乳类动物细胞衰老相关基因的寻找过程.     

Candidate Genes Associated with Susceptibility for SARS-Coronavirus

Assuming that no human had any previously acquired immunoprotection against severe acute respiratory syndrome coronavirus (SARS-CoV) during the 2003 SARS outbreak, the biological bases for possible difference in individual susceptibility are intriguing. However, this issue has never been fully elucidated. Based on the premise that SARS patients belonging to a given genotype group having a significantly higher SARS infection rate than others would imply that genotype group being more susceptible, we make use of a compartmental model describing disease transmission dynamics and clinical and gene data of 100 laboratory confirmed SARS patients from Chinese Han population in Taiwan to estimate the infection rates of distinct candidate genotype groups among these SARS-infected individuals. The results show that CXCL10(−938AA) is always protective whenever it appears, but appears rarely and only jointly with either Fgl2(+158T/*) or HO-1(−497A/*), while (Fgl2)(+158T/*) is associated with higher susceptibility unless combined with CXCL10/IP-10(−938AA), when jointly is associated with lower susceptibility. The novel modeling approach proposed, which does not require sizable case and control gene datasets, could have important future public health implications in swiftly identifying potential high-risk groups associated with being highly susceptible to a particular infectious disease.     

地塞米松降解新基因的探讨

探讨地塞米松降解代谢新基因,为构建高效、稳定的地塞米松降解基因工程菌提供思路。     

老年痴呆关联基因的研究进展

阿尔茨海默类痴呆（AD）是老年痴呆中最常见的一种,它以渐进性的神经功能退化并伴随着整体认知能力的下降为特征。早发性AD主要是由β-淀粉样前体蛋白（APP）基因和早老素基因突变引起,而与晚发性AD发病明显相关的只有载脂蛋白E-ε4 ( APOE-ε4)等位基因。但是APOE-ε4等位基因对AD发病既非充分又非必要,而且只能解释少于50%的AD的遗传变异。所以有必要进一步寻找与AD的关联基因。 Abstract:Dementia of the Alzheimer type (AD) is the leading cause of dementias for the elders.It is a progressively neurodegenerative disorder characterized by global cognitive decline.While most of the rare early-onset AD can be explained by mutations in APP gene and presenilin genes,the genetic etiology of the more common late-onset AD is only partly explained by the APOE-ε4 genotype.But the APOE-ε4 allele is neither necessary nor sufficient to cause disease and it can only account for less than one-half of the genetic variance of AD.Thus,more genes involved in AD are our special attention.     

心肌病关联基因家族与心肌发育和心肌病

心肌发育是个复杂的过程,受许多发育相关因子组成的复杂分子网络调控。这些基因的突变和结构异常可导致心肌发育异常和原发性心肌病。心肌病关联基因家族对心肌的胚胎发育、出生后心肌结构重塑以及心肌损伤修复等过程有重要作用。本文结合临床基因突变报道,对心肌病关联基因家族的功能和模式动物中的分子机制研究进行综述,以期深入了解该家族蛋白质在心肌发育及原发性心肌病中的作用。     

Novel Genes Associated with the Development of Carotid Paragangliomas

Molecular Biology - Carotid paragangliomas (CPGLs) are rare neuroendocrine tumors of the head and neck. “Germline” and somatic mutations in a number of genes were shown to be associated...     

Lysosomal Dysfunctions Associated with Mutations at Mouse Pigment Genes

Melanosomes and lysosomes share several structural and biosynthetic properties. Therefore, a large number of mouse pigment mutants were tested to determine whether genes affecting melanosome structure of function might also affect the lysosome. Among 31 mouse pigment mutants, six had 1.5- to 2.5-fold increased concentrations of kidney beta-glucuronidase. Three mutants, pale ear, pearl and pallid, had a generalized effect on lysosomal enzymes since there were coordinate increases in kidney beta-galactosidase and alpha-mannosidase. The effects of these three mutations are lysosome specific since rates of kidney protein synthesis and activities of three nonlysosomal kidney enzymes were normal. Also, the mutants are relatively tissue specific in that all had normal liver lysosomal enzyme concentrations.--A common dysfunction in all three mutants was a lowered rate of lysosomal enzyme secretion from kidney into urine. While normal C57BL/6J mice daily secreted 27 to 30% of total kidney beta-glucuronidase and beta-galactosidase, secretion of these two enzymes was coordinately depressed to 1 to 2%, 8 to 9% and 4 to 5% of total kidney enzyme in the pale-ear, pearl and pallid mutants, respectively. Although depressed lysosomal enzyme secretion is the major pigment mutant alteration, the higher lysomal enzyme concentrations in pearl and pallid may be partly due to an increase in lysosomal enzyme synthesis. In these mutants kidney glucuronidase synthetic rate was increased 1.4- to 1.5-fold.--These results suggest that there are several critical genes in mammals that control the biogenesis, processing and/or function of related classes of subcellular organelles. The mechanism of action of these genes is amenable to further analysis since they have been incorporated into congenic inbred strains of mice.     

Identification of Methylated Genes Associated with Aggressive Bladder Cancer

Approximately 500,000 individuals diagnosed with bladder cancer in the U.S. require routine cystoscopic follow-up to monitor for disease recurrences or progression, resulting in over $2 billion in annual expenditures. Identification of new diagnostic and monitoring strategies are clearly needed, and markers related to DNA methylation alterations hold great promise due to their stability, objective measurement, and known associations with the disease and with its clinical features. To identify novel epigenetic markers of aggressive bladder cancer, we utilized a high-throughput DNA methylation bead-array in two distinct population-based series of incident bladder cancer (n = 73 and n = 264, respectively). We then validated the association between methylation of these candidate loci with tumor grade in a third population (n = 245) through bisulfite pyrosequencing of candidate loci. Array based analyses identified 5 loci for further confirmation with bisulfite pyrosequencing. We identified and confirmed that increased promoter methylation of HOXB2 is significantly and independently associated with invasive bladder cancer and methylation of HOXB2, KRT13 and FRZB together significantly predict high-grade non-invasive disease. Methylation of these genes may be useful as clinical markers of the disease and may point to genes and pathways worthy of additional examination as novel targets for therapeutic treatment.     

主要干性基因与衰老相关基因表达水平的相互拮抗关系

目前广泛地利用传统的体细胞衰老理论和方法对成体干细胞衰老进行研究,忽视了成体干细胞特有的自我更新功能和相应的干性基因的作用.干性基因的下调可能是导致间充质干细胞衰老的主要原因.通过查阅相关资料发现主要干性基因与衰老相关基因表达水平的相互拮抗关系,这体现在以下4个方面:a.干细胞衰老伴随着干性基因的下调;b.干性基因表达抑制细胞的衰老;c.干性基因抑制衰老相关基因的表达;d.抑制衰老相关基因促进干性基因的表达.干性基因与衰老相关基因的表达水平存在相互拮抗关系,这为成体干细胞衰老可能源于成体干细胞的干性降低的观点提供了坚实的分子基础.     

基因芯片在骨骼肌老龄化相关基因表达谱中的应用

对老龄组大鼠 (30月龄 )和年轻对照组大鼠 (3月龄 )的腓肠肌超微结构进行观察 ,可以看到前者肌肉肌纤维萎缩伴有线粒体空泡变性。并进行总RNA抽提、mRNA纯化、探针制备 ,应用基因芯片筛选老龄化相关基因 ,两组大鼠骨骼肌重复出现的差异表达基因 12 7个 ,下调基因涉及能量代谢、信号转导 ,上调基因涉及蛋白质分解、细胞凋亡     

Identification of Genes Associated with Chlorophyll Accumulation in Flower Petals

Plants have an ability to prevent chlorophyll accumulation, which would mask the bright flower color, in their petals. In contrast, leaves contain substantial amounts of chlorophyll, as it is essential for photosynthesis. The mechanisms of organ-specific chlorophyll accumulation are unknown. To identify factors that determine the chlorophyll content in petals, we compared the expression of genes related to chlorophyll metabolism in different stages of non-green (red and white) petals (very low chlorophyll content), pale-green petals (low chlorophyll content), and leaves (high chlorophyll content) of carnation (Dianthus caryophyllus L.). The expression of many genes encoding chlorophyll biosynthesis enzymes, in particular Mg-chelatase, was lower in non-green petals than in leaves. Non-green petals also showed higher expression of genes involved in chlorophyll degradation, including STAY-GREEN gene and pheophytinase. These data suggest that the absence of chlorophylls in carnation petals may be caused by the low rate of chlorophyll biosynthesis and high rate of degradation. Similar results were obtained by the analysis of Arabidopsis microarray data. In carnation, most genes related to chlorophyll biosynthesis were expressed at similar levels in pale-green petals and leaves, whereas the expression of chlorophyll catabolic genes was higher in pale-green petals than in leaves. Therefore, we hypothesize that the difference in chlorophyll content between non-green and pale-green petals is due to different levels of chlorophyll biosynthesis. Our study provides a basis for future molecular and genetic studies on organ-specific chlorophyll accumulation.     

Polymorphisms in Ion Transport Genes Are Associated with Eggshell Mechanical Property

Eggshell mechanical property traits such as eggshell breaking strength (ESS), eggshell thickness (EST) and eggshell weight (ESW) are most common and important indexes to evaluate eggshell quality in poultry industry. Uterine ion transporters involve in eggshell formation and might be associated with eggshell mechanical property traits. In this study, 99 SNPs in 15 ion transport genes were selected to genotype 976 pedigreed hens of Rhode Island Red. ESS, EST and ESW were measured for each bird at 55 weeks of age. The association study showed that 14 SNPs in 8 genes were significantly related (p < 0.05) with at least one trait, and their contributions to phenotypic variance ranged from 0.23% to 4.14%. Both ATP2A3 and SLC4A5 had a significant effect on all the three traits. Strong linkage disequilibrium (LD) was detected among SNPs in four genes: ATP2A3, ITPR1, SLC8A3, SCNN1a. The significant effects of those diplotypes on eggshell mechanical property traits were found, and their contributions to phenotypic variance ranged from 0.50% to 0.70%. It was concluded that the identified SNPs and diplotypes in this study were potential markers influencing the eggshell mechanical properties, which could contribute to the genetic improvement of eggshell quality.     

Mycobacterium avium Genes Associated with the Ability To Form a Biofilm

Mycobacterium avium is widely distributed in the environment, and it is chiefly found in water and soil. M. avium, as well as Mycobacterium smegmatis, has been recognized to produce a biofilm or biofilm-like structure. We screened an M. avium green fluorescent protein (GFP) promoter library in M. smegmatis for genes involved in biofilm formation on polyvinyl chloride (PVC) plates. Clones associated with increased GFP expression ≥2.0-fold over the baseline were sequenced. Seventeen genes, most encoding proteins of the tricarboxylic acid (TCA) cycle and GDP-mannose and fatty acid biosynthesis, were identified. Their regulation in M. avium was confirmed by examining the expression of a set of genes by real-time PCR after incubation on PVC plates. In addition, screening of 2,000 clones of a transposon mutant bank constructed using M. avium strain A5, a mycobacterial strain with the ability to produce large amounts of biofilm, revealed four mutants with an impaired ability to form biofilm. Genes interrupted by transposons were homologues of M. tuberculosis 6-oxodehydrogenase (sucA), enzymes of the TCA cycle, protein synthetase (pstB), enzymes of glycopeptidolipid (GPL) synthesis, and Rv1565c (a hypothetical membrane protein). In conclusion, it appears that GPL biosynthesis, including the GDP-mannose biosynthesis pathway, is the most important pathway involved in the production of M. avium biofilm.     

Sporulation Genes Associated with Sporulation Efficiency in Natural Isolates of Yeast

Yeast sporulation efficiency is a quantitative trait and is known to vary among experimental populations and natural isolates. Some studies have uncovered the genetic basis of this variation and have identified the role of sporulation genes (IME1, RME1) and sporulation-associated genes (FKH2, PMS1, RAS2, RSF1, SWS2), as well as non-sporulation pathway genes (MKT1, TAO3) in maintaining this variation. However, these studies have been done mostly in experimental populations. Sporulation is a response to nutrient deprivation. Unlike laboratory strains, natural isolates have likely undergone multiple selections for quick adaptation to varying nutrient conditions. As a result, sporulation efficiency in natural isolates may have different genetic factors contributing to phenotypic variation. Using Saccharomyces cerevisiae strains in the genetically and environmentally diverse SGRP collection, we have identified genetic loci associated with sporulation efficiency variation in a set of sporulation and sporulation-associated genes. Using two independent methods for association mapping and correcting for population structure biases, our analysis identified two linked clusters containing 4 non-synonymous mutations in genes – HOS4, MCK1, SET3, and SPO74. Five regulatory polymorphisms in five genes such as MLS1 and CDC10 were also identified as putative candidates. Our results provide candidate genes contributing to phenotypic variation in the sporulation efficiency of natural isolates of yeast.     

Identifcation and Characterization of 177 Unreported Genes Associated with Liver Regeneration

The mammalian liver has a very strong regeneration capacity after partial hepa- tectomy (PH). To further learn the genes participating in the liver regeneration (LR), 551 cDNAs selected from subtracted cDNA libraries of the regenerating rat liver were screened by microarray, and their expression pro?les were studied by cluster and generalization analyses. Among them, 177 genes were identi?ed unre- ported and up- or down-regulated more than twofold at one or more time points after PH, of wh…