Deletional analysis of the murine IL-12 p35 promoter comparing IFN-gamma and lipopolysaccharide stimulation.

IL-12, pivotal to the development of Th1 cells and formed by association of p35 and p40 subunits, is made by macrophages and the macrophage cell line RAW264.7. In this study, the promoter for p35 was cloned and analyzed. The murine IL-12 p35 gene has promoters upstream from each of the first two exons. The exon 1 and exon 2 promoters, cloned into a reporter vector, were responsive to LPS or IFN-gamma/CD40 ligation in transfected RAW264.7 cells. The exon 2 promoter containing bp -809 to +1 has significant homology to the human p35 promoter. Thus, deletion analysis was performed to determine the regions required for responsiveness to LPS, CD40, and/or IFN-gamma. Base pairs -809 to -740 influenced responsiveness to LPS. In contrast, bp -740to -444 and bp -122 to -100 were required for responses to IFN-gamma, IFN-gamma/LPS, or IFN-gamma/CD40 ligation. Removal of bp -444 to -392 increased the response of the exon 2 promoter to each stimulant. IFN regulatory factor (IRF)-1 is involved in the activity of this promoter at bp -108 to -103 because levels of nuclear IRF-1 correlated with exon 2 promoter activity in response to IFN-gamma and IRF-1 overexpression stimulated and enhanced exon 2 promoter activity. Also, site or deletion mutation of the IRF-1 element at bp -108 to -103 reduced the responsiveness of the promoter and IRF-1 bound to an oligonucleotide containing bp -108 to -103. The data suggest that the response of the p35 promoter to IFN-gamma requires a distinct IRF-1 positive regulatory element at bp -108 to -103.     

Environmental distribution of the trichloroethene reductive dehalogenase gene (tceA) suggests lateral gene transfer among Dehalococcoides

The trichloroethene reductive dehalogenase gene (tceA) of Dehalococcoides spp. was detected in 12 of 21 trichloroethene-to-ethene dechlorinating enrichment cultures established from aquifer and sediment samples collected from diverse geographic locations in the USA. Analysis of the tceA chromosomal regions indicated that the tceA genes shared greater than 95% sequence identity, and all shared identical tceAB spacer sequences and tceB genes downstream of tceA. A putative transposable element (PTE) was present 1077 bp downstream of the tceB stop codon in three of eight chromosomal regions analyzed. Sequence identity was interrupted downstream of tceB and upstream or downstream of the PTE, suggesting that intrachromosomal or interchromosomal transfer of tceAB had occurred.     

奶牛产奶性状与乳房炎相关基因CpG含量及分布特征的比较分析

DNA甲基化是表观遗传学的重要组成部分,基因启动子区及第一外显子区的CpG甲基化通常抑制该基因的表达,而去甲基化则促进基因表达。已有的研究发现荷斯坦牛的乳房炎指标SCC(Somatic cell count)与产奶量呈较强负相关。文章分析并比较了这两类性状的相关基因的启动子区、第一外显子、下游2 000 bp序列中CpG含量及分布特征。结果表明,乳房炎相关基因的启动子、第一外显子中CpG含量显著低于产奶性状相关基因,而两类性状基因下游2 000 bp序列中CpG含量无显著性差异。另外,文中提出了两个量化基因序列中CpG特征的指标,一个是CpG平均距离,用来衡量序列中的CpG分布;另一个是条件概率p(G|C),用以量化序列中二核苷酸CpG随碱基C出现的可能性,并对两类基因的启动子和第一外显子区域的这两个指标做了统计检验。研究结果对产奶性状与乳房炎相关基因的DNA甲基化调控研究奠定了基础。     

粘虫核型多角体病毒凋亡抑制基因的定位,序列和启动子结构

以ＡｃＮＰＶ凋亡抑制基因ｐ３５为探针,与ＬｓＮＰＶＤＮＡ的限制性片段和ＬｓＮＰＶＤＮＡＥｃｏＲＶ片段杂交,发现ＥｃｏＲＶ５．５ｋｂ片段有强烈的杂交信号。将此片段亚克隆后,测定了１２４４ｂｐ序列,发现一个完整的ＯＲＦ,推导的３０２个氨基酸与ＡｃＮＰＶｐ３５蛋白有７０．４％的氨基酸同源性,证明所测ＯＲＦ为ＬｓＮＰＶ的ｐ３５基因。结构分析发现其５′端有早期基因启动子元件ＧＣ、ＡＣＧＴ和ＴＡＴＡｂｏｘ。有２２ｂｐ的顺向重复序列,包括由两个重叠的ＴＡＴＡｂｏｘ和上下游两个ＡＣＧＴｍｏｔｉｆ组成的两套启动子元件,这些结构特征与ＡｃＮＰＶ的凋亡抑制基因十分相似。     

Structural Analysis of rbcL Gene from an Endangered Plant，（Acanthopanax brachypus）

ＳｔｒｕｃｔｕｒａｌＡｎａｌｙｓｉｓｏｆｒｂｃＬＧｅｎｅｆｒｏｍａｎＥｎｄａｎｇｅｒｅｄＰｌａｎｔ,（Ａｃａｎｔｈｏｐａｎａｘｂｒａｃｈｙｐｕｓ）ＹＡＮＨｕａ－ｊｕｎ（严华军）;ＺＨＵＣｈｅｎｇ（朱）;ＷＵＮａｉ－ｈｕ（吴乃虎）（Ｉｎｓｔｉｔｕｔｅｏ...     

Location of DNA sequences complementary to small nuclear repeat RNA (fr 3-RNA) in relation to DNA sequences coding for albumin and alpha-fetoprotein in rat liver cells

Rat liver nuclei contain a 29-nucleotides-long RNA (fr 3-RNA) which is transcribed from middle repetitive DNA sequences. By Southern analysis of restriction fragments of rat albumin and alpha-fetoprotein genomic clones, DNA sequences complementary to this RNA were detected on a 4.6 kbp Eco RI fragment located 600 bp downstream from the termination exon of the albumin gene and on a 2 kbp Eco RI-HindIII fragment located 10 kbp downstream from the restriction fragment containing the alpha-fetoprotein site. No sequence complementary to this RNA was found either in the introns of exons of both genes or in the regions extending 7 kbp upstream from the first albumin exon and 10 kbp upstream of the first alpha-fetoprotein exon. We concluded that sequences complementary to fr 3-RNA are present at the 3'-end flanking regions of the rat albumin and alpha-fetoprotein gene complexes.