Functional characterization of a natural retinoic acid responsive element.

Retinoic acid receptor (RAR) and thyroid hormone receptor (T3R) are thought to bind as dimers to a T3 responsive element (T3REpal) comprised of inverted repeats of the half-site motif GGTCA. However, a RA responsive element (beta RARE) was previously identified in the promoter of the RAR beta 2 gene which contains two direct repeats of the motif GTTCA spaced by a six nucleotide gap. We now demonstrate the ability of RAR alpha, beta and gamma to bind to and transactivate through this element and that the two direct repeats comprise the beta RARE. Surprisingly, the GTTCA motifs rearranged to form a palindrome do not confer RA responsiveness to a heterologous promoter. Furthermore, no significant level of transactivation is detected by ligand-activated RAR through the Moloney murine leukaemia virus T3RE, which comprises two direct repeats of the sequence GGTCA/C spaced by a five nucleotide gap. Similarly, T3R does not induce gene expression through the beta RARE. This study establishes the preference of T3R to transactivate through direct repeats spaced by a five nucleotide gap as opposed to a six nucleotide gap. In contrast, RAR appears to be more flexible with respect to spacing requirements between repeats, although higher levels of transactivation are obtained through direct repeats spaced by a six nucleotide gap. Interestingly, although some elements mediate either RA or T3 induction, changing a single nucleotide in the MoMLV T3RE with a five nucleotide spacing creates a promiscuous RA/T3 responsive element.     

连续近交下家猪微卫生基因组杂合度与经济性状的相关性研究

从已这位于家猪０１、０２、１１、１３、１７、１８号染色体上的遗传标记中选用５６个具有足够覆盖率的微卫生标记,对１个连续５个代近交家系共１９２个头家猪进行了基因组扫描.平均微卫生标记杂合度估计基因组杂合度（ＧＨ）。ＧＨ对于屠宰重（ＳＷＴ）和日均屠宰重（ＡＤＳＧ）为显著正相关效应,对于背膘厚（ＢＦＤＰ）的相关效应不显著且方向也不一致。ＧＨ的相关效应随近交世代递增而呈非线性变化趋势;ＧＨ对于ＳＷＴ和ＡＤＳＧ的相关效应在近交前２世代呈上升趋势。２代分别到达最大值（２２．４３kg和０．１３２kg/d）,此后随近交世代的递增而递减;ＧＨ对于ＢＦＤＰ的相关效应随世代递增而非线性递减。微卫星杂合度的相关效应在不同染色体间存在较大差异,对ＳＷＴ和ＡＳＤＧ均表现为正效应,其中又以１３号染色体标记杂合度的相关效应为最大（６．３０kg和０．０３２kg／d)其次依镒为１号、１７号、１８号、２号和１１号。各染色体微卫星标记杂合度对于ＢＦＤＰ的相关效应估值的标准误差大,且效应方向不一致（１８号染色体来正效应,其余染色体为负效应）,由引得到如下３点启示,第一,对于经济性状重要的基因（e.g.QTL)不同是均衡分布于各杂染色体上,此差异可能反应出生物性状决定在染色体以及分子分上上的差异;第二,由于基因,基因互作和且背景效应的复杂性,基因（组）杂合度与性能间不为简单的相关,学可能由于标记数目不够或是标记选择不适当而误导;第三,由于高度近交（如连续同胞交配）下较高的连锁不平衡所致,有害基因可能以较高的概率民中性标记连锁遗传,由此可能部分或全部抵消杂合优势的表现,甚至出现杂合劣势。     

Type II Transmembrane Serine Proteases

Analysis of genome and expressed sequence tag data bases at the turn of the millennium unveiled a new protease family named the type II transmembrane serine proteases (TTSPs) in a Journal of Biological Chemistry minireview (Hooper, J. D., Clements, J. A., Quigley, J. P., and Antalis, T. M. (2001) J. Biol. Chem. 276, 857–860). Since then, the number of known TTSPs has more than doubled, and more importantly, our understanding of the physiological functions of individual TTSPs and their contribution to human disease has greatly increased. Progress has also been made in identifying molecular substrates and endogenous inhibitors. This minireview summarizes the current knowledge of the rapidly advancing TTSP field.     

Comparative anatomical study of the carotid circulation in gundis, with implications for their evolutionary history

The carotid circulation pattern in gundis (Ctenodactylidae) is examined and compared with that of typical members of the classical rodent suborders. On this basis their probable phylogenetic relationships and systematic position are discussed. Together with other recent investigations, the unique pattern of cephalic arterial supply emphasizes the isolated position of the ctenodactylids.     

Characterization of a human granulocyte differentiation antigen (CDw15) commonly recognized by monoclonal antibodies

Many different anti-human granulocyte monoclonal antibodies recognize the same carbohydrate antigen which contains the trisaccharide 3-fucosyl-N-acetyllactosamine. The antigen is expressed mainly on two cell surface glycoproteins of molecular weights around 105 K and 160 K which are apparently not members of the LFA-1 family of proteins. Although specific for granulocytes in blood, the antigen is expressed on a wide range of non-haemopoietic cell types.     

Biosynthesis of P1-di-N-acetyl-alpha-chitobiosyl P2-dolichyl pyrophosphate in calf pancreas microsomes

Calf pancreas microsomes incubated with UDP-N-acetyl-D-[14C] glucosamine in the presence of Mn2+ incorporated radioactivity into P1-2-acetamido-2-deoxy-D-glucopyranosyl P2-dolichyl pyrophosphate and P1-di-N-acetyl-alpha-chitobiosyl P2-dolichyl pyrophosphate. The formation of both glycolipids was enhanced to the same extent by exogenous dolichyl phosphate. Labeled P1-di-N-acetyl-alpha-chitobiosyl P2-dolichyl pyrophosphate was formed from synthetic P1-2-acetamido-2-deoxy-alpha-D-glucopyranosyl P2-dolichyl pyrophosphate and from prelabeled pancreatic P1-2-acetamido-2-deoxy-alpha-D-glucopyranosyl P2-dolichyl pyrophosphate without the addition of divalent cation. Upon thin layer chromatography, it had the same mobility as synthetic P1-di-N-acetyl-alpha-chitobiosyl P2-dolichyl pyrophosphate recently synthesized by Warren et al. (Warren, C. D., Herscovics, A., and Jeanloz, R. W. (1977) Carbohydr. Res., in press), but was different from the synthetic compound prepared by Wedgwood et al. (Wedgwood, J. F., Warren, C. D., Jeanloz, R. W., and Strominger, J. L. (1974) Proc. Natl. Acad. Sci. U. S. A. 71, 5022-5026).     

YKL-40 protein expression in normal adult human tissues – an immunohistochemical study

YKL-40, a 40 kDa plasma protein, is secreted by macrophages, neutrophils, chondrocytes, vascular smooth muscle cells and cancer cells. High plasma YKL-40 is found in patients with inflammatory diseases and cancer, but it is not known how the protein is expressed in tissues. This immunohistochemical study was carried out with the purpose of mapping and grading cytoplasmic expression of YKL-40 in normal human tissue. Bovine serum albumin had to be used for pre-incubation in order to eliminate background staining of YKL-40. The majority of cells were stained, but the intensity varied, not just among different cell types but also within the same cell type. Cells known for exerting a high metabolic activity, i.e., high producing cells or cells with high turn-over, tended to show the most intense cytoplasmic staining, which was weak or lacking in cells with no or little activity. Many of these positive cells probably contribute to the YKL-40 found in plasma in healthy subjects in accordance with previous findings on their in vitro production of the protein. In conclusion, all cells with a functioning nucleus appeared to be capable of expressing YKL-40 in their cytoplasm, the intensity of which was dependent on cellular activity. An erratum to this article can be found at     

New probes used for IS1245 and IS1311 restriction fragment length polymorphism of Mycobacterium avium subsp. avium and Mycobacterium avium subsp. hominissuis isolates of human and animal origin in Norway

Background  

Mycobacterium avium is an environmental mycobacterium that can be divided into the subspecies avium, hominissuis, paratuberculosis and silvaticum. Some M. avium subspecies are opportunistic pathogens for animals and humans. They are ubiquitous in nature and can be isolated from natural sources of water, soil, plants and bedding material. Isolates of M. avium originating from humans (n = 37), pigs (n = 51) and wild birds (n = 10) in Norway were examined by IS1245 and IS1311 RFLP using new and specific probes and for the presence of IS901 and ISMpa1 by PCR. Analysis and generation of a dendrogram were performed with the software BioNumerics.     

Evidence for a matriptase-prostasin proteolytic cascade regulating terminal epidermal differentiation

Recent gene ablation studies in mice have shown that matriptase, a type II transmembrane serine protease, and prostasin, a glycosylphosphatidylinositol-anchored membrane serine protease, are both required for processing of the epidermis-specific polyprotein, profilaggrin, stratum corneum formation, and acquisition of epidermal barrier function. Here we present evidence that matriptase acts upstream of prostasin in a zymogen activation cascade that regulates terminal epidermal differentiation and is required for prostasin zymogen activation. Enzymatic gene trapping of matriptase combined with prostasin immunohistochemistry revealed that matriptase was co-localized with prostasin in transitional layer cells of the epidermis and that the developmental onset of expression of the two membrane proteases was coordinated and correlated with acquisition of epidermal barrier function. Purified soluble matriptase efficiently converted soluble prostasin zymogen to an active two-chain form that formed SDS-stable complexes with the serpin protease nexin-1. Whereas two forms of prostasin with molecular weights corresponding to the prostasin zymogen and active prostasin were present in wild type epidermis, prostasin was exclusively found in the zymogen form in matriptase-deficient epidermis. These data suggest that matriptase, an autoactivating protease, acts upstream from prostasin to initiate a zymogen cascade that is essential for epidermal differentiation.