Cloning and sequencing of cellulase cDNA from Aspergillus kawachii and its expression in Saccharomyces cerevisiae

The cDNA encoding the endo--1,4-glucanase (carboxymethylcellulase; CMCase-I) from Aspergillus kawachii IFO 4308 was cloned. Nucleotide-sequence analysis of the cloned cDNA insert showed a 717-bp open reading frame that encoded a protein of 239 amino-acid residues. The predicted amino-acid sequence of the mature protein had considerable homology with the protein sequence of the FI-CMCase of Aspergillus aculeatus. The cDNA was introduced into Saccharomyces cerevisiae. The expressed enzyme had carboxylmethylcellulase acitivity, identified by clear zones on a CMC-agar plate after Congo Red staining.     

Cloning and nucleotide sequence of the genomic ribonuclease T2 gene (rntB) from Aspergillus oryzae

Summary Using synthetic oligonucleotide probes, we have cloned a genomic DNA sequence encoding a ribonuclease (RNase) T₂ gene (rntB) from Aspergillus oryzae on a 4.8 kb HindIII fragment. DNA sequence analysis of the RNase T₂ revealed the following: (1) The gene is arranged as five exons and four introns; (2) The deduced amino acid sequence contains 239 amino acid residues of the mature enzyme. In addition, there exist 17 amino acid residues thought to be a signal peptide sequence at the N-terminus and 20 amino acid residues at the C-terminus; (3) The nucleotide sequence of the rntB gene is homologous to those of the RNase Rh gene from Rhizopus niveus and the S2 stylar glycoprotein gene of Nicotiana alata with degree of about 51% and 47%, respectively; (4) A. oryzae and A. nidulans transformed with the cloned rntB gene had much higher ribonuclease T₂ activity than wild-type strains.     

Nucleotide sequence of the gene for pre-apocytochrome f in the spinach plastid chromosome

Summary We have characterized a cloned fragment of the spinach plastid chromosome encoding the gene for apocytochrome f. Northern blot analysis and hybrid selection translation discloses that the gene is expressed. From the nucleotide sequence, we deduce that the protein contains 285 amino acids and an amino-terminal signal sequence of 35 amino acid residues. The calculated molecular mass of pre-apocytochrome f is 35.3 kd. The clustering of hydrophobic residues indicates that the processed protein (31.3 kd) possesses only a single anchoring transmembrane domain close to the C terminus, and that 75% of the polypeptide chain including the heme-binding site protrudes into the thylakoid lumen. This topology resembles that reported for beef heart mitochondrial cytochrome c₁.     

The 49 K subunit of NADH: ubiquinone reductase (complex I) from Neurospora crassa mitochondria: primary structure of the gene and the protein

Summary The primary structure of the 49 K subunit of the respiratory chain NADH:ubiquinone reductase (complex I) from Neurospora crassa was determined by sequencing cDNA, genomic DNA and the N-terminus of the mature protein. The sequence lengths correlate to a molecular mass of 54002 daltons for the preprotein and 49239 daltons for the mature protein. The presequence consists of 42 amino acids of typical composition for sequences which target nuclear-encoded proteins into mitochondria. The mature protein consists of 436 amino acids and shows 64% similarity to a 49 K subunit of bovine heart NADH:ubiquinone reductase and 33% to a predicted translation product of an open reading frame in the chloroplast DNAs of Marchantia polymorpha and Nicotiana tabacum. Evidence for an iron-sulfur cluster in the subunit is discussed.     

Analysis of cDNA clones encoding the entire precursor-polypeptide for ferredoxin: NADP+ oxidoreductase from spinach

Summary In this paper, we report the structural characterization of several spinach ferredoxin-NADP⁺ oxidoreductase (FNR) cDNAs ranging in size from 0.9 to 1.5 kilobases. A comparison of the deduced amino acid sequence with the known amino acid sequence determined for the spinach protein establishes that 1.4–1.5 kpb inserts span the full length of the mature protein (314 amino acid residues; M_r = 35,382). These also include an N-terminal 55 amino acid transit peptide as well as maximally 171 and 214 nucleotide 5′ and 3′ untranslated sequences, respectively. Evidence has been obtained that various forms of FNR arise from at least two similar genes. The FNR precursor (369 amino acid residues) has a calculated molecular mass of 41.2 kDa. Comparison of the transit peptide with transit peptides from two other stromal proteins shows little similarity at the level of primary sequence but some common features in secondary structure predictions.     

Cloning and characterization of a chitinase (CHIT42) cDNA from the mycoparasitic fungus Trichoderma harzianum

A cDNA of Trichoderma harzianum (chit42), coding for an endochitinase of 42 kDa, has been cloned using synthetic oligonucleotides corresponding to aminoacid sequences of the purified chitinase. The cDNA codes for a protein of 423 amino acids. Analysis of the N-terminal amino-acid sequence of the chitinase, and comparison with that deduced from the nucleotide sequence, revealed post-translational processing of a putative signal peptide of 22 amino acids and a second peptide of 12 amino acids. The chit42 sequence presents overall similarities with filamentous fungal and bacterial chitinases and to a lesser extent with yeast and plant chitinases. The deduced aminoacid sequence has putative catalytic, phosphorylation and glycosylation domains. Expression of chit42 mRNA is strongly induced by chitin and chitin-containing cell walls and is subjected to catabolite repression. Southern analysis shows that it is present as a single-copy gene in T. harzianum. chit42 is also detected in several tested mycoparasitic and non-mycoparasitic fungal strains.     

Cloning, characterization, and expression of a novel secretory lipase-like gene from Clonorchis sinensis

A secretory lipase-like gene was isolated from total cDNA of adult Clonorchis sinensis. The gene has an open reading frame of 1,218 bp long and encodes for a protein of 406 amino acids including a putative signal peptide of 20 amino acids. The deduced amino acid sequence including signal peptide has 42–45% identity with lipase of other species and two typical enzymic active sites that contain consensus sequence (Gly-X-Ser-X-Gly) of lipase. The cDNA encoding this protein was subcloned into pET-28a (+) expression vector and expressed in Escherichia coli. The expressed fusion protein has a molecular mass of about 45 kDa. Prediction of signal peptide and Western blot analysis indicated that the secretory lipase-like protein is an excretory–secretory product of C. sinensis. Immunostaining revealed that the secretory lipase-like protein was localized in the tegument of the adult worm and metacercaria. These results provide basis for further studies on the nutrition taking and invasion of C. sinensis mediated by the secretory lipase-like protein.     

Characterization of a Mis12 homologue in <Emphasis Type="Italic">Arabidopsis thaliana</Emphasis>

The centromere/kinetochore represents an important complex on chromosomes that contains a large number of proteins and facilitates accurate chromosome segregation during cell division. Fission yeast Mis12 and its human homologue hMis12 have been identified as essential kinetochore components. Although homologues have been suggested to exist in plants, their function remains to be determined. In this study the full-length cDNA of the Mis12 homologue from Arabidopsis thaliana (AtMIS12) was successfully cloned by RACE-and RT-PCR and the DNA sequence determined. The 238 amino acid sequence deduced from the cDNA contains two conserved blocks and a coiled-coil motif, despite the poor overall similarity to fission yeast and human Mis12. The antibody raised against a partial peptide of AtMIS12 recognized a 27-kDa protein corresponding to the predicted molecular weight. Immunofluorescence labeling using the antibody revealed that AtMIS12 localizes at centromeric regions, like the centromeric histone H3 variant HTR12, throughout the cell cycle. These results indicate that AtMIS12 is a constitutive component of Arabidopsis kinetochores.     

Molecular characterization of the pathogen-specific, 34-kilodalton membrane immunogen of Treponema pallidum.

The 34-kilodalton (kDa) antigen of Treponema pallidum subsp. pallidum (T. pallidum) is a pathogen-specific integral membrane protein. DNA sequence analysis of the cloned gene revealed an open reading frame encoding a primary product of 204 residues with a molecular mass of 22,087 daltons. Sequences that correspond to a consensus Escherichia coli promoter and a ribosome-binding site were found upstream from the AUG start codon that begins the open reading frame, suggesting that the cloned gene can use its own regulatory sequences for expression. Examination of the deduced amino acid sequence revealed the presence of a typical procaryotic leader peptide 19 amino acids long; processing results in a mature molecule with a molecular mass of 20,123 daltons. Pulse-chase experiments with E. coli minicells confirmed that the 34-kDa antigen is synthesized as a higher-molecular-weight precursor that is processed to a mature form with the electrophoretic mobility that is characteristic for this protein. The presence in the leader peptide of the sequence Phe-Ser-Ala-Cys suggested that the 34-kDa antigen is a proteolipid. Although hydropathy analysis of the deduced amino acid sequence of the mature 34-kDa antigen predicted that the molecule was primarily hydrophilic, both the native and recombinant 34-kDa molecules displayed hydrophobic biochemical behavior by fractionating into the detergent phase after extraction of intact organisms with Triton X-114. Cell fractionation experiments with E. coli showed that the 34-kDa molecule was localized in both the inner and outer membranes of the recombinant host. The combined data demonstrate that the 34-kDa antigen is an integral membrane protein that behaves in a biochemically consistent manner in both T. pallidum and E. coli.     

Expression of human IgE-binding factor (sCD23) inEscherichia coli

Previously, we cloned cDNA coding for type II Fc receptor for human IgE (CD23 or FcERII). A fragment of this cDNA coding for soluble IgE-binding factor fused with a fragment of human interleukin-3 gene was cloned in pBT-IL-3-sCD23 plasmid. It is demonstrated thatE. coli strain JM109 (pBT-IL-3-sCD23) expresses the hybrid protein with a yield of 10–15% total cell protein. The recombinant product is represented by equal amounts of two polypeptides with molecular weights of about 24 and 32 kD. Immunological analysis and determination of the amino acid sequence of the N-terminal ends of these polypeptides show that a protein with a molecular weight of 24 kD results from proteolysis of the full-size (32 kD) hybrid protein. The preparation obtained can be used for the development of test kits for CD23. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, No. 6, pp. 690–694, June, 1996     

Molecular cloning, sequencing and expression of a serine proteinase inhibitor gene from Toxoplasma gondii

A cDNA clone from a Toxoplasma gondii tachyzoite cDNA library encoding a serine proteinase inhibitor (serpin) was isolated. The 1376 bp cDNA sequence encodes a 294 amino acid protein with a putative signal peptide of 23 amino acids resulting in a mature protein with a predicted mass of 30,190 Da and a pI of 4.86. This protein has internal sequence similarity of residues 30-66, 114-150, 181-217 and 247-283 indicating a four-domain structure. The four domains exhibit high identity to serine proteinase inhibitors belonging to the non-classical Kazal-type family. The gene is single copy in the tachyzoite haploid genome of RH strain and was amplified by polymerase chain reaction (PCR). Several introns were identified. The sequence encoding the mature protein was amplified by PCR, cloned into the pQE30 vector and expressed in Escherichia coli. Specific antiserum generated against the recombinant protein was used in immunoblot assay and two bands of 38 and 42 kDa were detected in a whole parasite homogenate. The recombinant protein showed trypsin-inhibitory activity, one of the two potential specificities. We discuss the possible roles that T. gondii serpin(s) may play in the survival of the tachyzoites in the host.     

Isolation and primary structure of the ERG9 gene of Saccharomyces cerevisiae encoding squalene synthetase

Summary The ERG9 gene of Saccharomyces cerevisiae has been cloned by complementation of the erg9-1 mutation which affects squalene synthetase. From the 5kkb insert isolated, the functional gene has been localized on a DNA fragment of 2.5 kb. The presence of squalene synthetase activity in E. coli bearing the yeast DNA fragment isolated, indicates that the structural gene encoding squalene synthetase has been cloned. The sequence of the 2.5 kb fragment contains an open reading frame which could encode a protein of 444 amino acids with a deduced relative molecular mass of 51 600. The amino acid sequence reveals one to four potential transmembrane domains with a hydrophobic segment in the C-terminal region. The N-terminus of the deduced protein strongly resembles the signal sequence of yeast invertase suggesting a specific mechanism of integration into the membranes of the endoplasmic reticulum.     

Primary sequence of a putative non-ATPase subunit of the 26S proteasome from Entamoeba histolytica is similar to the human and yeast S2 subunit

The cDNA coding for a non-ATPase S2 subunit of the 26S proteasome from Entamoeba histolytica was cloned from a cDNA library (EhS2). The open reading frame has 2529 bp and the deduced amino acid sequence encodes a protein with a calculated molecular mass of 92,000 Da. EhS2 has 29–35% identity with the three other known S2 subunit sequences of yeasts and humans. Received: 23 August 1998 / Accepted: 2 November 1998     

Cloning and sequencing of the mumps virus fusion protein gene

The fusion protein (F) gene of mumps virus was cloned from a cDNA library constructed from infected cell mRNA. The F-specific plasmids were identified by hybridization to a degenerate oligonucleotide probe whose sequence was deduced from the N-terminal amino acid sequence of the F₂ protein. The complete nucleotide sequence of the F gene was determined. The gene is 1786 nucleotides long and encodes one long open reading frame of 538 amino acids. The F protein has a 19-amino acid signal peptide cleaved between Cys and Val residues. The cleavage site for activation of the F₀ protein into themature F_1,2 is ArgArgHisLysArg. A stretch of 30 hydrophobic amino acids near the C-terminus of the protein is followed by serveral charged amino acids and appears to serve as the anchoring domain for the protein in the lipid bilayer. The F gene of mumps virus is highly related to the F gene of the paramyxovirus SV-5.     

Cloning and expression of a chitinase gene from the hyperparasitic fungus Aphanocladium album

Summary Recombinant clones from a cDNA library of an Aphanocladium album chitinase-overproducing mutant strain were isolated by screening with antiserum against a 39 kDa chitinase purified from this hyperparasitic fungus. Analysis of the isolated positive clones indicated that most of them carried the same cDNA. A cDNA from this group was used as a hybridization probe to isolate an 8 kb DNA fragment from a genomic library of the wild-type strain. The chitinase 1 gene was mapped to this fragment by two independent approaches. Its partial DNA sequence was in perfect agreement with an amino-terminal peptide sequence obtained by sequencing 23 amino acids of the 39 kDa chitinase. Its transfer in Fusarium oxysporum resulted in a transformant producting both a protein of about 39 kDa that cross-reacted with the chitinase antiserum and a chitinase activity that was inhibited by the same antiserum. Northern blot analysis indicates that the cloned chitinase gene was subject to catabolite repression and appeared inducible by chitin.     

点带石斑鱼抗菌肽hepcidin基因克隆及其成熟肽的原核融合表达

目的克隆点带石斑鱼hepcidin前体cDNA序列,构建其成熟肽pET-32a融合表达载体。结论根据已报道的硬骨鱼类hepcidin cDNA序列设计简并引物,以点带石斑鱼（Epinephelelus malabaricus）肝脏为材料,通过RT-PCR扩增hepcidin cDNA序列,用比对推导的氨基酸序列预测其成熟肽段。再将成熟肽cDNA序列亚克隆至pET-32a构建原核表达并进行原核融合表达。结果获得点带石斑鱼hepcidin-like抗菌肽前体cDNA序列1条,GenBank登录号为HM474788。DNA序列的Blast分析以及推导氨基酸序列NJ进化树分析表明,HM474788是点带石斑鱼第1条报道的抗菌肽hepcidin cDNA序列。成功构建了该序列的成熟肽原核融合表达载体pET-32a-hepcidin（EM1）,并成功在大肠杆菌origami（DE3）中表达。结论成功克隆点带石斑鱼hepcidin-like抗菌肽前体cDNA序列,成熟肽成功在大肠杆菌中融合表达,为后续有关石斑鱼hepcidin的功能研究与实践应用奠定重要基础。     

Location and nucleotide sequence of the pre-apocytochrome f gene on the Oenothera hookeri plastid chromosome (Euoenothera plastome I)

Summary The gene for pre-apocytochrome f has been mapped by blot hybridization on a 2.4 kbp HindIII fragment of the circular plastid chromosome of Oenothera hookeii employing probes from the corresponding spinach gene. The gene is located distal to the gene for the ATP synthase subunit alpha, at the border of the 45 kbp inversion that distinguishes spinach and Oenothera plastid chromosomes. Both genes are transcribed in the same direction. Nucleotide sequence analysis reveals a single open reading frame encoding 318 amino acids of which 285 comprise the mature polypeptide and another 33 residues represent probably a N-terminal signal sequence. The putative pre-sequence is 2 residues shorter than those known from the spinach, wheat and pea protein. The deduced amino acid sequences of f cytochromes from the four plant species show over 80% conservation, maintaining the structural characteristics of the protein.     

Viral properties, primary structure and phylogenetic analysis of the coat protein of an Olive latent virus 1 isolate from Olea europaea L

An Olive latent virus 1 isolate designated GM6, obtained from a Portuguese olive tree, was characterized and the coat protein gene sequenced and analysed. The purified virus particles showed to be isometric with ca. 30 nm in diameter and contained a single-stranded RNA species with ca. 3.7 kb. The dsRNA profile obtained from infected tissues showed three major species with ca. 3.7, 1.5 and 1.3 kbp. SDS-PAGE analysis revealed a major peptide with an apparent molecular mass of 32 kDa identified as the coat protein. A viral genome region containing the coat protein gene was amplified by RT-PCR and the cDNA was cloned and sequenced. The coat protein gene revealed to be 813 nucleotides long and encode a peptide with 270 amino acid residues and an estimated Mr of 29,851. Alignment of the deduced amino acid sequence with that of other necroviruses showed a higher identity with OLV-1 tulip isolate (97.7%) than with OLV-1 citrus isolate (87.7%). The consensus pattern of the coat protein 'S' domain is conserved in GM6 isolate coat protein sequence, except in amino acid 151, leucine. This is the first report on the coat protein sequence of an OLV-1 olive isolate.     

Cloning and functional expression of Rpn1, a regulatory-particle non-ATPase subunit 1, of proteasome from Trypanosoma cruzi

Non-lysosomal protein degradation in eukaryotic cells involves a proteolytic complex referred to as 26S proteasome that consists of a 20S core particle and one or two 19S regulatory particles. We have cloned the gene RPN1 encoding Rpn1 (regulatory-particle non-ATPase subunit 1), one of the largest subunits of proteasome, from Trypanosoma cruzi. It contains 2712 bp and encodes 904 amino acid residues with a calculated molecular mass of 98.2 kDa and an isoelectric point of 5.2. The predicted amino acid sequence of the trypanosomatid Rpn1 shares 39.0 and 32.0% overall identities with human Rpn1 and Saccharomyces cerevisiae Nas1 (non-ATPase subunit 1), an Rpn1 homolog, respectively, while the sequence identities among T. cruzi, Plasmodium falciparum, and Entamoeba histolytica Rpn1 are approximately 30%. T. cruzi Rpn1 contains nine repeats of about 36 amino acid residues conserved in Rpn1s from various organisms. T. cruzi RPN1 is located on the 2300- and 1900-kb chromosomal DNA, displays a putative allelic variation as RPN1-1 and RPN1-2 with 98.8% identity between these two putative gene products, and is transcribed from both alleles at a comparable level throughout the three developmental stages of the parasite, epimastigotes, trypomastigotes, and amastigotes. The expression of the trypanosomatid Rpn1 in the temperature-sensitive nas1 yeast mutant rescued the growth defect at the restrictive temperature, indicating that Rpn1 functions as a Nas1 and probably assembles into the 19S regulatory particle of the yeast 26S proteasome.     

Molecular cloning and characterization of a cDNA encoding the N-acetyl-beta-D-glucosaminidase homologue of Paracoccidioides brasiliensis.

A cDNA encoding the N-acetyl-beta-D-glucosaminidase (NAG) protein of Paracoccidioides brasiliensis, Pb NAG1, was cloned and characterized. The 2663-nucleotide sequence of the cDNA consisted of a single open reading frame encoding a protein with a predicted molecular mass of 64.73 kDa and an isoeletric point of 6.35. The predicted protein includes a putative 30-amino-acid signal peptide. The protein as a whole shares considerable sequence similarity with 'classic' NAG. The primary sequence of Pb NAG1 was used to infer phylogenetic relationships. The amino acid sequence of Pb NAG1 has 45, 31 and 30% identity, respectively, with homologous sequences from Trichoderma harzianum, Aspergillus nidulans and Candida albicans. In particular, striking homology was observed with the active site regions of the glycosyl hydrolase group of proteins (family 20). The expected active site consensus motif G X D E and catalytic Asp and Glu residues at positions 373 and 374 were found, reinforcing that Pb NAG1 belongs to glycosyl hydrolase family 20. The nucleotide sequence of Pb nag1 and its flanking regions have been deposited, along with the amino acid sequence of the deduced protein, in GenBank under accession number AF419158.