scholarly journals Identification and Sequencing of β-Myrcene Catabolism Genes from Pseudomonas sp. Strain M1

1999 ◽  
Vol 65 (7) ◽  
pp. 2871-2876 ◽  
Author(s):  
Sandra Iurescia ◽  
Andrea M. Marconi ◽  
Daniela Tofani ◽  
Augusto Gambacorta ◽  
Annalisa Paternò ◽  
...  

ABSTRACT The M1 strain, able to grow on β-myrcene as the sole carbon and energy source, was isolated by an enrichment culture and identified as a Pseudomonas sp. One β-myrcene-negative mutant, called N22, obtained by transposon mutagenesis, accumulated (E)-2-methyl-6-methylen-2,7-octadien-1-ol (or myrcen-8-ol) as a unique β-myrcene biotransformation product. This compound was identified by gas chromatography-mass spectrometry. We cloned and sequenced the DNA regions flanking the transposon and used these fragments to identify the M1 genomic library clones containing the wild-type copy of the interrupted gene. One of the selected cosmids, containing a 22-kb genomic insert, was able to complement the N22 mutant for growth on β-myrcene. A 5,370-bp-long sequence spanning the region interrupted by the transposon in the mutant was determined. We identified four open reading frames, named myrA,myrB, myrC, and myrD, which can potentially code for an aldehyde dehydrogenase, an alcohol dehydrogenase, an acyl-coenzyme A (CoA) synthetase, and an enoyl-CoA hydratase, respectively. myrA, myrB, andmyrC are likely organized in an operon, since they are separated by only 19 and 36 nucleotides (nt), respectively, and no promoter-like sequences have been found in these regions. ThemyrD gene starts 224 nt upstream of myrA and is divergently transcribed. The myrB sequence was found to be completely identical to the one flanking the transposon in the mutant. Therefore, we could ascertain that the transposon had been inserted inside the myrB gene, in complete agreement with the accumulation of (E)-2-methyl-6-methylen-2,7-octadien-1-ol by the mutant. Based on sequence and biotransformation data, we propose a pathway for β-myrcene catabolism in Pseudomonas sp. strain M1.

1984 ◽  
Vol 4 (9) ◽  
pp. 1871-1879 ◽  
Author(s):  
N Abovich ◽  
M Rosbash

We cloned and sequenced the second gene coding for yeast ribosomal protein 51 (RP51B). When the DNA sequence of this gene was compared with the DNA sequence of RP51A (J.L. Teem and M. Rosbash, Proc. Natl. Acad. Sci. U.S.A. 80:4403--4407, 1983), the following conclusions emerged: both genes code for a protein of 135 amino acids; both open reading frames are interrupted by a single intron which occurs directly after the initiating methionine; the open reading frames are 96% homologous and code for the same protein with the exception of the carboxy-terminal amino acid; DNA sequence homology outside of the coding region is extremely limited. The cloned genes, in combination with the one-step gene disruption techniques of Rothstein (R. J. Rothstein, Methods Enzymol. 101:202-211, 1983), were used to generate haploid strains containing mutations in the RP51A or RP51B genes or in both. Strains missing a normal RP51A gene grew poorly (180-min generation time versus 130 min for the wild type), whereas strains carrying a mutant RP51B were relatively normal. Strains carrying mutations in the two genes grew extremely poorly (6 to 9 h), which led us to conclude that RP51A and RP51B were both expressed. The results of Northern blot and primer extension experiments indicate that strains with a wild-type copy of the RP51B gene and a mutant (or deleted) RP51A gene grow slowly because of an insufficient amount of RP51 mRNA. The growth defect was completely rescued with additional copies of RP51B. The data suggest that RP51A contributes more RP51 mRNA (and more RP51 protein) than does RP51B and that intergenic dosage compensation, sufficient to rescue the growth defect of strains missing a wild-type RP51A gene, does not take place.


1984 ◽  
Vol 4 (9) ◽  
pp. 1871-1879
Author(s):  
N Abovich ◽  
M Rosbash

We cloned and sequenced the second gene coding for yeast ribosomal protein 51 (RP51B). When the DNA sequence of this gene was compared with the DNA sequence of RP51A (J.L. Teem and M. Rosbash, Proc. Natl. Acad. Sci. U.S.A. 80:4403--4407, 1983), the following conclusions emerged: both genes code for a protein of 135 amino acids; both open reading frames are interrupted by a single intron which occurs directly after the initiating methionine; the open reading frames are 96% homologous and code for the same protein with the exception of the carboxy-terminal amino acid; DNA sequence homology outside of the coding region is extremely limited. The cloned genes, in combination with the one-step gene disruption techniques of Rothstein (R. J. Rothstein, Methods Enzymol. 101:202-211, 1983), were used to generate haploid strains containing mutations in the RP51A or RP51B genes or in both. Strains missing a normal RP51A gene grew poorly (180-min generation time versus 130 min for the wild type), whereas strains carrying a mutant RP51B were relatively normal. Strains carrying mutations in the two genes grew extremely poorly (6 to 9 h), which led us to conclude that RP51A and RP51B were both expressed. The results of Northern blot and primer extension experiments indicate that strains with a wild-type copy of the RP51B gene and a mutant (or deleted) RP51A gene grow slowly because of an insufficient amount of RP51 mRNA. The growth defect was completely rescued with additional copies of RP51B. The data suggest that RP51A contributes more RP51 mRNA (and more RP51 protein) than does RP51B and that intergenic dosage compensation, sufficient to rescue the growth defect of strains missing a wild-type RP51A gene, does not take place.


Gene ◽  
2002 ◽  
Vol 298 (2) ◽  
pp. 195-201 ◽  
Author(s):  
Hisashi Nishigawa ◽  
Kenro Oshima ◽  
Shigeyuki Kakizawa ◽  
Hee-Young Jung ◽  
Tsutomu Kuboyama ◽  
...  

1998 ◽  
Vol 71 (1) ◽  
pp. 11-19 ◽  
Author(s):  
YUJI YASUKOCHI ◽  
TOSHIO KANDA ◽  
TOSHIKI TAMURA

To clone the Bombyx xanthine dehydrogenase (XDH) gene as a dominant marker for silkworm transgenesis, we performed nested reverse transcriptase–polymerase chain reaction (RT-PCR) using embryonic mRNA and primers designed from the conserved region of Drosophila and rat XDH genes. Sequencing of amplified 180 bp fragments showed that two different sequences were present in the fragments. Since both possessed striking similarity to XDH genes of other organisms, we considered these to be portions of silkworm XDH genes and designated them BmXDH1 and BmXDH2. Subsequently we cloned separately the entire region of the two cDNAs by PCR using phage DNA of an embryonic cDNA library and sequenced them. The two cDNAs were around 4 kb in size and possessed complete open reading frames. The deduced amino acid sequences of the two BmXDHs were very similar to each other and to those of other organisms. The expression pattern of wild-type larvae basically followed the tissue specificity of the enzyme and no significant difference was observed between the two XDH genes. The expression of both genes was detected in the XDH-deficient mutants, oq and og, but non-synonymous substitutions were specifically detected in the BmXDH1 of the oq mutant. In addition, a length polymorphism of the second intron of the BmXDH1 co-segregated with the oq translucent phenotype, suggesting that deficiency in BmXDH1 is the cause of the oq translucent phenotype.


2009 ◽  
Vol 53 (5) ◽  
pp. 1907-1911 ◽  
Author(s):  
Esther Izquierdo ◽  
Yimin Cai ◽  
Eric Marchioni ◽  
Saïd Ennahar

ABSTRACT Enterococcus faecium IT62, a strain isolated from ryegrass in Japan, produces three bacteriocins (enterocins L50A, L50B, and IT) that have been previously purified and the primary structures of which have been determined by amino acid sequencing (E. Izquierdo, A. Bednarczyk, C. Schaeffer, Y. Cai, E. Marchioni, A. Van Dorsselaer, and S. Ennahar, Antimicrob. Agents Chemother., 52:1917-1923, 2008). Genetic analysis showed that the bacteriocins of E. faecium IT62 are plasmid encoded, but with the structural genes specifying enterocin L50A and enterocin L50B being carried by a plasmid (pTAB1) that is separate from the one (pTIT1) carrying the structural gene of enterocin IT. Sequencing analysis of a 1,475-bp region from pTAB1 identified two consecutive open reading frames corresponding, with the exception of 2 bp, to the genes entL50A and entL50B, encoding EntL50A and EntL50B, respectively. Both bacteriocins are synthesized without N-terminal leader sequences. Genetic analysis of a sequenced 1,380-bp pTIT1 fragment showed that the genes entIT and entIM, encoding enterocin IT and its immunity protein, respectively, were both found in E. faecium VRE200 for bacteriocin 32. Enterocin IT, a 6,390-Da peptide made up of 54 amino acids, has been previously shown to be identical to the C-terminal part of bacteriocin 32, a 7,998-Da bacteriocin produced by E. faecium VRE200 whose structure was deduced from its structural gene (T. Inoue, H. Tomita, and Y. Ike, Antimicrob. Agents Chemother., 50:1202-1212, 2006). By combining the biochemical and genetic data on enterocin IT, it was concluded that bacteriocin 32 is in fact identical to enterocin IT, both being encoded by the same plasmid-borne gene, and that the N-terminal leader peptide for this bacteriocin is 35 amino acids long and not 19 amino acids long as previously reported.


2000 ◽  
Vol 74 (16) ◽  
pp. 7411-7421 ◽  
Author(s):  
Xiaoyan Zhan ◽  
Manfred Lee ◽  
Jianqiao Xiao ◽  
Fenyong Liu

ABSTRACT A transposon derived from Escherichia coliTn3 was introduced into the genome of murine cytomegalovirus (MCMV) to generate a pool of viral mutants, including two recombinant viruses that contained the transposon sequence within open reading frames m09 and M83. Our studies provide the first direct evidence to suggest that m09 is not essential for viral replication in mouse NIH 3T3 cells. Studies in cultured cells and in both BALB/c-Byj and CB17 severe combined immunodeficient (SCID) mice indicated that the transposon insertion is stable during viral propagation both in vitro and in vivo. Moreover, the virus that contained the insertion mutation in m09 exhibited a titer similar to that of the wild-type virus in the salivary glands, lungs, livers, spleens, and kidneys of both the BALB/c and SCID mice and was as virulent as the wild-type virus in killing the SCID mice when these animals were intraperitoneally infected with these viruses. These results suggest that m09 is dispensable for viral growth in these organs and that the presence of the transposon sequence in the viral genome does not significantly affect viral replication in vivo. In contrast, the virus that contained the insertion mutation in M83 exhibited a titer of at least 60-fold lower than that of the wild-type virus in the organs of the SCID mice and was attenuated in killing the SCID mice. These results demonstrate the utility of using the Tn3-based system as a mutagenesis approach for studying the function of MCMV genes in both immunocompetent and immunodeficient animals.


2004 ◽  
Vol 186 (20) ◽  
pp. 6714-6720 ◽  
Author(s):  
Christopher D. Herring ◽  
Frederick R. Blattner

ABSTRACT Expression of an amber suppressor tRNA should result in read-through of the 326 open reading frames (ORFs) that terminate with amber stop codons in the Escherichia coli genome, including six pseudogenes. Abnormal extension of an ORF might alter the activities of the protein and have effects on cellular physiology, while suppression of a pseudogene could lead to a gain of function. We used oligonucleotide microarrays to determine if any effects were apparent at the level of transcription in glucose minimal medium. Surprisingly, only eight genes had significantly different expression in the presence of the suppressor. Among these were the genes yaiN, adhC, and yaiM, forming a single putative operon whose likely function is the degradation of formaldehyde. Expression of wild-type yaiN was shown to result in repression of the operon, while a suppression-mimicking allele lacking the amber stop codon and extended 7 amino acids did not. The operon was shown to be induced by formaldehyde, and the genes have been renamed frmR, frmA, and frmB, respectively.


2001 ◽  
Vol 183 (1) ◽  
pp. 257-263 ◽  
Author(s):  
Frank Bardischewsky ◽  
Cornelius G. Friedrich

ABSTRACT A transposon Tn5-mob insertional mutant ofParacoccus pantotrophus GB17, strain TP43, was unable to oxidize thiosulfate aerobically or to reduce nitrite anaerobically, and the cellular yields were generally decreased by 11 to 20%. Strain TP43 was unable to form functional c-type cytochromes, as determined by difference spectroscopy and heme staining. However, formation of apocytochromes and their transport to the periplasm were not affected, as seen with SoxD, a c-type cytochrome associated with the periplasmic sulfite dehydrogenase homologue. The Tn5-mob-containing DNA region of strain TP43 was cloned into pSUP205 to produce pE18TP43. With the aid of pE18TP43 the corresponding wild-type gene region of 15 kb was isolated from a heterogenote recombinant to produce pEF15. Sequence analysis of 2.8 kb of the relevant region uncovered three open reading frames, designated ORFA, ccdA, and ORFB, with the latter being oriented divergently. ORFA and ccdA were constitutively cotranscribed as determined by primer extension analysis. In strain TP43 Tn5-mob was inserted into ccdA. The deduced ORFA product showed no similarity to any protein in databases. However, the ccdA gene product exhibited similarities to proteins assigned to different functions in bacteria, such as cytochrome c biogenesis. For these proteins at least six transmembrane helices are predicted with the potential to form a channel with two conserved cysteines. This structural identity suggests that these proteins transfer reducing equivalents from the cytoplasm to the periplasm and that the cysteines bring about this transfer to enable the various specific functions via specific redox mediators such as thioredoxins. CcdA of P. pantotrophus is 42% identical to a protein predicted by ORF2, and its location within thesox gene cluster coding for lithotrophic sulfur oxidation suggested a different function.


1995 ◽  
Vol 41 (3) ◽  
pp. 217-226 ◽  
Author(s):  
Margarita Beatriz Viejo ◽  
Josefina Enfedaque ◽  
Joan Francesc Guasch ◽  
Santiago Ferrer ◽  
Miguel Regué

The gene encoding bacteriocin 28b from Serratia marcescens N28b (bss gene) has been cloned in Escherichia coli and its nucleotide sequence has been determined. The genetic determinants coding for other well-characterized bacteriocins from enterobacteria (colicins) are located in plasmids and they have always been shown to contain a gene responsible for immunity located downstream from the bacteriocin structural gene. In some cases there is another gene located downstream from the immunity gene, which is responsible for bacteriocin release. Analysis of bacteriocin 28b release and the sensitivity to this bacteriocin of E. coli strains harbouring recombinant plasmids containing the bss gene showed that bacteriocin 28b is not released from the cell in these strains and that their phenotypic insensitivity is not associated with any region close to the structural gene. The nucleotide sequence of the region downstream from the bss gene contains two putative open reading frames transcribed in the opposite direction to the bss gene. These open reading frames apparently encode proteins that seem not to be involved in bacteriocin immunity or release. Moreover, a S. marcescens N28b genomic library was screened and no immunity gene was found. Therefore, bacteriocin 28b differs greatly from the bacteriocins from other enterobacteria, and in the following senses it is unique: firstly, the gene encoding bacteriocin 28b seems to be located on the chromosome, and secondly, insensitivity to this bacteriocin in S. marcescens N28b is not associated with the expression of an immunity gene.Key words: bacteriocin, pore-forming colicins, immunity, Serratia marcescens.


2001 ◽  
Vol 67 (2) ◽  
pp. 733-741 ◽  
Author(s):  
Cécile J. B van der Vlugt-Bergmans ◽  
Mariët J. van der Werf

ABSTRACT A monoterpene ɛ-lactone hydrolase (MLH) from Rhodococcus erythropolis DCL14, catalyzing the ring opening of lactones which are formed during degradation of several monocyclic monoterpenes, including carvone and menthol, was purified to apparent homogeneity. It is a monomeric enzyme of 31 kDa that is active with (4R)-4-isopropenyl-7-methyl-2-oxo-oxepanone and (6R)-6-isopropenyl-3-methyl-2-oxo-oxepanone, lactones derived from (4R)-dihydrocarvone, and 7-isopropyl-4-methyl-2-oxo-oxepanone, the lactone derived from menthone. Both enantiomers of 4-, 5-, 6-, and 7-methyl-2-oxo-oxepanone were converted at equal rates, suggesting that the enzyme is not stereoselective. Maximal enzyme activity was measured at pH 9.5 and 30°C. Determination of the N-terminal amino acid sequence of purified MLH enabled cloning of the corresponding gene by a combination of PCR and colony screening. The gene, designated mlhB(monoterpene lactone hydrolysis), showed up to 43% similarity to members of the GDXG family of lipolytic enzymes. Sequencing of the adjacent regions revealed two other open reading frames, one encoding a protein with similarity to the short-chain dehydrogenase reductase family and the second encoding a protein with similarity to acyl coenzyme A dehydrogenases. Both enzymes are possibly also involved in the monoterpene degradation pathways of this microorganism.


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