柔嫩艾美耳球虫Serpin基因在293T细胞中的表达

为了检测柔嫩艾美耳球虫(Eimeria tenella,Et)丝氨酸蛋白酶抑制剂(Serine protease inhibitor,Serpin)基因(EtSerpin)在真核细胞293T中的表达情况,以Et孢子化卵囊cDNA为模板,经PCR扩增含完整Serpin开放阅读框的序列,将其克隆至pGEM-Teasy载体,构建pGEM-Teasy-EtSerpin质粒,双酶切回收目的片段后与相应酶切的真核表达载体pCAGGS连接,构建真核重组表达质粒pCAGGS-EtSerpin.该重组质粒经酶切和测序鉴定正确后转染293T细胞,用间接免疫荧光法和Western blot鉴定EtSerpin基因的表达情况,间接免疫荧光实验可以检测到红色荧光,Western blot结果显示出大小约45.5kDa的目的蛋白条带,结果表明构建的EtSerpin可以在293T细胞中获得表达.     

Recent progress in understanding the diversity of the human ov-serpin/clade B serpin family

The inhibitory mechanism against proteases is important in the maintenance of homeostasis or health in the body. The human ovalbumin serpin (ovserpin)/ clade B serpin family is one group of the human serpins, a family of serine protease inhibitors. They have acquired diversity in the profiles of target proteases, inhibitory mechanisms, and localization patterns during their evolution. Most serpins target serine proteases, however, some ov-serpins target only cysteine proteases or both serine and cysteine proteases and furthermore, several ov-serpins do not possess inhibitory activities. Although the ov-serpins act primarily as intracellular serpins, some show extracellular and nuclear localizations. Such diversity enables the ov-serpins to play multiple physiological roles in the body. Recent analyses have revealed that the functions of human ov-serpins are more diversified than we previously knew. In this article, we describe recent progress in our understanding of how the human ov-serpin/clade B serpin family demonstrates diversity.     

Human clade B serpins (ov-serpins) belong to a cohort of evolutionarily dispersed <Emphasis Type="Italic">intracellular</Emphasis> proteinase inhibitor clades that protect cells from promiscuous proteolysis

Serpins are unique among the various types of active site proteinase inhibitors because they covalently trap their targets by undergoing an irreversible conformational rearrangement. Members of the serpin superfamily are present in the three major domains of life (Bacteria, Archaea and Eukarya) as well as several eukaryotic viruses. The human genome encodes for at least 35 members that segregate evolutionarily into nine (A-I) distinct clades. Most of the human serpins are secreted and circulate in the bloodstream where they reside at critical checkpoints intersecting self-perpetuating proteolytic cascades such as those of the clotting, thrombolytic and complement systems. Unlike these circulating serpins, the clade B serpins (ov-serpins) lack signal peptides and reside primarily within cells. Most of the human clade B serpins inhibit serine and/or papain-like cysteine proteinases and protect cells from exogenous and endogenous proteinase-mediated injury. Moreover, as sequencing projects expand to the genomes of other species, it has become apparent that intracellular serpins belonging to distinct phylogenic clades are also present in the three major domains of life. As some of these serpins also guard cells against the deleterious effects of promiscuous proteolytic activity, we propose that this cytoprotective function, along with similarities in structure are common features of a cohort of intracellular serpin clades from a wide variety of species.Received 24 June 2003; received after revision 16 July 2003; accepted 5 August 2003     

Neuroserpin: a serpin to think about

Proteinases and their inhibitors play important roles in neural development, homeostasis and disease. Neuroserpin is a member of the serine proteinase inhibitor (serpin) superfamily that is secreted from the growth cones of neurons and inhibits the enzyme tissue-type plasminogen activator (tPA). The temporal and spatial pattern of neuroserpin expression suggests a role in synaptogenesis and is most prominent in areas of the brain that participate in learning, memory and behaviour. Neuroserpin also provides neuronal protection in pathologies such as cerebral ischaemia and epilepsy by preventing excessive activity of tPA. Point mutations in neuroserpin cause aberrant conformational transitions and the formation of loop-sheet polymers that are retained within the endoplasmic reticulum of neurons, forming inclusion bodies that underlie an autosomal dominant dementia that we have called familial encephalopathy with neuroserpin inclusion bodies or FENIB. We review here the role of neuroserpin and other proteinase inhibitors in brain development, function and disease. Received 25 February 2005; received after revision 16 November 2005; accepted 28 November 2005