Molecular cloning and responsive expression of macrophage expressed gene from small abalone Haliotis diversicolor supertexta

The complete cDNA sequence of macrophage expressed gene (saMpeg1), a perforin-like molecule, was isolated from small abalone (Haliotis diversicolor supertexta) by homology cloning and rapid amplification of cDNA ends (RACE). The full-length cDNA of saMpeg1 was 2781 bp, consisting of a 5'-terminal untranslated region (UTR) of 252 bp, a 3'-terminal UTR of 342 bp with a signal sequence TAA and a poly (A) tail, and an open reading frame of 2184 bp. The deduced protein (saMpeg1) was composed of 728 amino acids, and contains the cytolytic "helix-turn-helix" domain of perforin (residues 171-218), of which the alpha-helices are amphipathic as are those of perforin. A putative single transmembrane domain is located at residues 667-689, and a modified furin cleavage site (KRRRK; residues 689-693) immediately follows. The result of real time quantitative PCR showed that saMpeg1 was highly expressed at 8h and 96 h post-injection of the Gram-negative bacterium Vibrio parahaemolyticus, but there was no change after TBT exposure. The structural similarity to mammalian perforin and the different gene expression level to bacterial infection and TBT exposure suggest that saMpeg1 may play a role in the immune response against microorganisms in small abalone.     

Expression and localization of transcripts of MT5-MMP and its related MMP in the ovary of the medaka fish Oryzias latipes

cDNA clones of MT5-matrix metalloproteinase (MT5-MMP) and a related protein (designated MT5-MMP-del) were isolated by screening the cDNA library and by 3'-rapid amplification of cDNA ends using an ovary RNA of the medaka fish Oryzias latipes. The MT5-MMP clone encodes a protein of 546 amino acids while the MT5-MMP-del clone encodes a protein of 431 amino acids. Compared with mammalian counterparts, the fish MT5-MMP and MT5-MMP-del both lack the signal peptide and a part of the prodomain. The fish MT5-MMP and MT5-MMP-del were different in that the latter did not have the stem/transmembrane/cytoplasmic domain. The two fish MMPs were expressed in the ovary, testis, brain, and intestine. In the ovary, MT5-MMP mRNA was expressed in the oocytes of small growing follicles. In contrast, MT5-MMP-del mRNA was found in the stromal interstitial cells. These results strongly suggest that a MT5-MMP/gelatinase A cascade may possibly operate in the process of spawning and/or other events associated with ovulated oocytes or fertilized eggs of the medaka fish.     

Molecular cloning and expression analysis of alpha 2-macroglobulin in the kuruma shrimp, Marsupenaeus japonicus

The cDNA encoding the kuruma shrimp, Marsupenaeus japonicus alpha(2)-macroglobulin (alpha(2)M) was obtained by screening a haemocyte cDNA library and 5' RACE PCR amplification. The full length cDNA of 4748 bp contains an open reading frame of 4518 nucleotides that translates into a 1505-amino acid putative peptide, with a 5'untranslated region (UTR) of 59 bp and a 3'UTR of 171 bp. The open reading frame encodes an N-terminal signal sequence of 17 residues and a mature protein of 1488 residues. The entire amino acid sequence is similar to the alpha(2)M sequences of arthropods (30-31% identity), mammals (26-27% identity) and fish (25-28% identity). The M. japonicus alpha(2)M sequence contains putative functional domains including a bait region, an internal thiol ester site, and a receptor-binding domain, which are present in mammalian alpha(2)Ms. In a healthy shrimp, the mRNA of alpha(2)M was mainly expressed in haemocytes. In addition, the expression level of alpha(2)M mRNA was dramatically increased by through time upon oral administration of peptidoglycan (PG), which is an immune stimulant. The highest expression of alpha(2)M mRNA was observed 7 days after feeding with PG. These results suggest that the shrimp alpha(2)M is an important molecule in immune system.     

Identification of the fourth member of the mammalian endoprotease family homologous to the yeast Kex2 protease. Its testis-specific expression.

We used the polymerase chain reaction to identify a mouse testis cDNA that represented another member of a growing class of mammalian endoproteases involved in the processing of precursor proteins. This cDNA encoded a 655-residue protein, designated PC4, containing a bacterial subtilisin-like catalytic domain closely related to those of the recently characterized precursor-processing endoproteases, furin, PC1/PC3, PC2, and Kex2. Within this domain, the amino acid sequence of PC4 was 70, 58, 55, and 45% identical with those of mouse furin, mouse PC1/PC3, mouse PC2, and yeast Kex2, respectively. Northern blot analysis indicated that the PC4 mRNA was detectable only in the testes after the 20th day of postnatal development. Moreover, this message was mainly expressed in the round spermatids. These data suggest that PC4 represents a prime candidate for a precursor-processing endoprotease in the testicular germ cells and that its gene expression is regulated during spermatogenesis.     

A novel serine protease with clip domain from scallop Chlamys farreri

The serine proteases with clip domain are involved in various innate immune functions in invertebrate such as antimicrobial activity, cell adhesion, pattern recognition and regulation of the prophenoloxidase system. A serine protease with clip-domain cDNA (Cf SP) was obtained by Expressed sequence taggings (ESTs) method and rapid amplification of cDNA ends (RACE). The Cf SP full-length cDNA was of 1,152 bp, including a 5'-terminal untranslated region (UTR) of 63 bp, a 3'-terminal UTR of 81 bp with a canonical polyadenylation signal sequence AATAAA and a poly(A) tail, and an open reading frame of 1,008 bp encoding a polypeptide of 336 amino acids with a putative signal peptide of 19 amino acids. The deduced amino acid sequence of Cf SP contained an amino-terminal clip domain with three disulfide bonds formed six conserved Cys residues, a carboxyl-terminal trypsin-like domain with the conserved His-Asp-Ser catalytic triad, and a low complexity linker sequence. The Cf SP was strongly expressed in hemocytes and the mRNA expression of Cf SP was up-regulated and increased 3.2-fold and 2.6-fold at 16 h after injection of Vibrio anguillarum and Micrococcus luteus. The results suggested that Cf SP gene might be involved in immune response of Gram-negative and Gram-positive microbial infection in scallop.     

Molecular characterization of two isoforms of ZFAND3 cDNA from the Japanese quail and the leopard gecko, and different expression patterns between testis and ovary

Zing finger AN1-type domain 3 (ZFAND3), also known as testis expressed sequence 27 (Tex27), is a gene found in the mouse testis, but its physiological function is unknown. We identified the full-length sequences of two isoforms (short and long) of ZFAND3 cDNA from Japanese quail and leopard gecko. This is the first cloning of avian and reptilian ZFAND3 cDNA. The two isoforms are generated by alternative polyadenylation in the 3'UTR and have the same ORF sequences encoding identical proteins. There were highly conserved regions in the 3'UTR of the long form near the polyadenylation sites from mammals to amphibians, suggesting that the features for determining the stability of mRNA or translation efficiency differ between isoforms. The deduced amino acid sequence of ZFAND3 has two putative zinc finger domains, an A20-like zinc finger domain at the N-terminal and an AN1-like zinc finger domain at the C-terminal. Sequence analysis revealed an additional exon in the genomic structures of the avian and reptilian ZFAND3 genes which is not present in mammals, amphibians, or fish, and this exon produces additional amino acid residues in the A20-like zinc finger domain. Expression analysis in Japanese quail revealed that the expression level of ZFAND3 mRNA was high in not only the testis but also the ovary, and ZFAND3 mRNA was expressed in both spermatides of the testis and oocytes of the ovary. While the short form mRNA was mainly expressed in the testis, the expression level of the long form mRNA was high in the ovary. These results suggest that ZFAND3 has physiological functions related to germ cell maturation and regulatory mechanisms that differ between the testis and ovary.     

Molecular cloning and immune responsive expression of a novel C-type lectin gene from bay scallop Argopecten irradians

C-type lectins are Ca(2+)-dependent carbohydrate-recognition proteins that play crucial roles in innate immunity. The cDNA of C-type lectin (AiCTL1) in the bay scallop Argopecten irradians was cloned by expressed sequence tag (EST) and RACE techniques. The full-length cDNA of AiCTL1 was 660 bp, consisting of a 5'-terminal untranslated region (UTR) of 30 bp and a 3' UTR of 132 bp with a polyadenylation signal sequence AATAAA and a poly(A) tail. The AiCTL1 cDNA encoded a polypeptide of 166 amino acids with a putative signal peptide of 20 amino acid residues and a mature protein of 146 amino acids. The deduced amino acid sequence of AiCTL1 was highly similar to those of the C-type lectins from other animals and contained a typical carbohydrate-recognition domain (CRD) of 121 residues, which has four conserved disulfide-bonded cysteine residues that define the CRD and two additional cysteine residues at the amino terminus. AiCTL1 mRNA was dominantly expressed in the hemocytes of the bay scallop. The temporal expression of AiCTL1 mRNA in hemocytes was increased by 5.7- and 4.9-fold at 6h after injury and 8h after injection of bacteria, respectively. The structural features, high similarity and expression pattern of AiCTL1 indicate that the gene may be involved in injury healing and the immune response in A. irradians.     

野桑蚕酚氧化酶原基因cDNA的分子克隆及其特征

酚氧化酶在昆虫的免疫防御机制中起着重要作用。利用RT-PCR和RACE方法,克隆了野桑蚕酚氧化酶原基因,获得了其cDNA序列。该序列长2 134 bp,含有一个2 082 bp的完整开放阅读框,编码一个由693个氨基酸残基组成的蛋白质。推导的氨基酸序列与其他鳞翅目昆虫PPO2基因相应氨基酸序列有较高的同源性,该序列具有它们的PPO基因所共有的典型特征。组织特异性表达分析表明了该基因在野桑蚕5龄幼虫的血细胞、体壁、头部、精巢、卵巢、脂肪体和中肠等组织及其不同的发育阶段均有表达。这些结果为进一步研究野桑蚕酚氧化酶原基因的功能提供了分子基础。     

Characterization of bmp15 and its regulation by human chorionic gonadotropin in the follicle of gibel carp (Carassius auratus gibelio)

Bone morphogenetic protein (BMP15) is a member of the transforming growth factor β (TGF-β) superfamily with a key role in regulating follicle development in mammals and birds. However, potential ovarian roles of BMPs remain unexplored in teleosts. In this study, the full-length sequences of bmp15 were obtained using rapid-amplification of cDNA ends (RACE). The full-length cDNA sequence of bmp15 is 2217 bp which contained 214 bp 5'-UTR and 845 bp 3'-UTR. The open reading frame (ORF) sequence of bmp15 is 1158 bp, encoding a predicted protein of 385 amino acid residues. BMP15 has a specific RXXR protease cleavage site of TGF-β superfamily (is RIRR) and six conserved cysteine residues. Using real-time quantitative PCR revealed that bmp15 mRNA was largely expressed in the ovary and testis and mostly in oocytes within the follicle, slightly expressed in muscle, liver and pituitary. BMP15 is mainly present at stage I follicles by real-time quantitative PCR and immunohistochemistry. Phylogenetic analysis showed that gibel carp bmp15 was similar to bmp15 of zebrafish and other fish species. Treatment with human chorionic gonadotropin (hCG) in isolated follicles of gibel carp in vitro showed altered bmp15 mRNA expression: when treated with 10 ng/mL hCG for 10h, the expression level of bmp15 was significantly increased. However, with proceeding cultivation, the expression level of BMP15 mRNA decreased. The results of this study indicate that bmp15 may play a key role during development of follicles in gibel carp, especially in early stage follicles.     

Erk2 in ovarian development of green mud crab Scylla paramamosain

We identified extracellular signal-regulated kinase 2 (erk2) from green mud crab, Scylla paramamosain, in this article. It was originally identified from an expressed sequence tag fragment from a normalized gonadal cDNA library. 5' Rapid amplification of cDNA end (RACE) technique was used to obtain the 5' untranslated region (UTR). The full-length cDNA of Sp-erk2 is 1516 bp, including a 5'-terminal UTR of 19 bp, an open-reading frame of 1098 bp, and a 3'-terminal UTR of 399 bp. The translated protein is 365 amino acids in length with a predicted molecular weight of 42 kDa, which is the same as other species. It is the first time that the expression of Sp-erk2 in different stages of ovary development of crustacean was analyzed, and the result showed that the expression of Sp-erk2 increased gradually with ovarian development, with a peak in the mature phase. In situ hybridization histochemistry was used to clarify the detail of expression. Positive signals illustrated that Sp-erk2 mRNA is present in follicular cells when the ovary is in early stages, and in both follicular cells and oocytes when it is in mature phases. All above suggest that Sp-erk2 is important for ovarian development.     

小地老虎几丁质酶基因的克隆与序列分析

利用昆虫几丁质酶对几丁质的调控作用破坏几丁质新陈代谢的平衡来防治害虫, 在生物防治策略中具有很大的发展潜力。从处于预蛹期的小地老虎Agrotls ipsilon (Hufnagel)体中肠内提取总的RNA, 经反转录, 利用cDNA末端快速扩增技术（RACE）获得了几丁质酶基因的cDNA序列。该基因序列已经登录GenBank并获得登录号为EU035316。该序列长度为2 823个碱基, 含有一个1 674个碱基的开放读码框。开放读码框编码558个氨基酸残基, 预测的分子量为62.5 kDa, 等电点5.12。推导得到的氨基酸序列含有2个N-位糖基化位点,20个O-位糖基化位点, 含有2个几丁质酶所具有的保守序列：N-端的催化区和C-端的几丁质结合区。氨基酸序列与其他昆虫, 特别是鳞翅目昆虫的几丁质酶高度同源。     

Cloning and identification of methionine synthase gene from Pichia pastoris

Methionine synthase (MS) is grouped into two classes. Class One MS (MetH) and Class Two MS (MetE) share no homology and differ in their catalytic model. Based on the conserved sequences of metE genes from different organisms, a segment of the metE gene was first cloned from Pichia pastoris genomic DNA by PCR, and its 5‘ and 3‘ regions were further cloned by 5‘- and 3‘-rapid amplification of cDNA ends (RACE), respectively. The assembled sequence reveals an open reading frame encoding a polypeptide of 768 residues, and the deduced product shares 76% identity with MetE of Saccharomyces cerevisiae. P. pastoris methionine synthase (PpMetE) consists of two domains common to MetEs. The active site is located in the C-terminal domain, in which the residues involved in the interaction of zinc with substrates are conserved. Homologous expression of PpMetE in P. pastoris was achieved, and the heterologous expression of PpMetE in the S. cerevisiae strain XJB3-1D that is MetE-defective restored the growth of the mutant on methionine-free minimal media. The gene sequence has been submitted to GenBank/EMBL/DDBJ under accession No. AY601648.     

绵羊肌球蛋白轻链2基因的分子克隆与表达分析

肌球蛋白轻链2蛋白是哺乳动物肌球蛋白的重要成员之一。获得其基因序列,并对其特征和表达进行分析,可为进一步研究功能奠定基础。本研究以小尾寒羊背最长肌为试验材料,采用RACE等方法对绵羊肌球蛋白轻链2基因的cDNA序列进行克隆和测序、利用相关生物学软件对所得cDNA序列进行生物信息学预测、并利用qRT-PCR和Western印迹法对其在绵羊各种组织中的表达进行分析。结果获得该基因cDNA序列全长为776 bp,提交至GenBank中获得相应的登录号为KJ710702;该序列中的498 bp的开放读码框编码含有166个氨基酸残基的蛋白质。预测发现该蛋白质无信号肽和二硫键,但存在N-糖基化和磷酸化位点;二级结构中以α-螺旋为主;蛋白质序列比较发现绵羊MYL2与小鼠、人、大鼠、猪、牛等哺乳动物的同源性均在95%以上。mRNA和蛋白质表达谱均显示该基因在绵羊心肌中表达量最高,其次为背最长肌。