Melanin biosynthesis in the fungusCurvularia lunata(teleomorph:Cochliobolus lunatus)

2003 ◽  
Vol 49 (2) ◽  
pp. 110-119 ◽  
Author(s):  
Tea Lanisnik Rižner ◽  
Michael H Wheeler

Curvularia lunata (teleomorph: Cochliobolus lunatus) is a known plant and human pathogen. Tricyclazole, a specific inhibitor of pentaketide melanin biosynthesis, blocked the biosynthesis of melanin in Curvularia lunata and caused the accumulation of the melanin metabolites flaviolin and 2-hydroxyjuglone. This showed that melanin in Curvularia lunata is produced by a pentaketide pathway from 1,8-dihydroxynaphthalene. The 1,3,8-trihydroxynaphthalene reductase (3HNR) gene, associated with the melanin pathway of Curvularia lunata, was identified and characterized. An alignment of 3HNR sequences enabled the design of primers covering conserved regions. A PCR-amplified fragment of Curvularia lunata genomic DNA was used for screening the cDNA library. Three independent cDNA clones revealed an 801-bp open reading frame encoding a 267 amino acid protein. The protein was expressed in Escherichia coli and purified to homogeneity. The predicted amino acid sequence of the 28.6-kDa protein demonstrated homology to other fungal 3HNR and other members of the short-chain dehydrogenase super family. Northern analyses revealed that 3HNR from Curvularia lunata is expressed synchronously with melanization after 3 days of Curvularia lunata growth in malt extract medium. No 3HNR reductase gene expression nor melanization was observed when Curvularia lunata was grown in yeast nitrogen base medium.Key words: melanin, fungi, Curvularia lunata, Cochliobolus lunatus, trihydroxynaphthalene reductase.

1993 ◽  
Vol 105 (2) ◽  
pp. 589-600 ◽  
Author(s):  
T. Maekawa ◽  
R. Kuriyama

Using a human autoantibody, SP-H, we identified a 200–230 kDa mitotic MAP in a variety of mammalian cell lines which shows affinity for the minus end of microtubules and also becomes associated with the spindle pole during mitosis. To examine the detailed structure and functional organization of the protein, the gene coding for the end-specific MAP was isolated and characterized by screening a human placenta lambda gt11 expression library using SP-H as a probe. Overlapping cDNA clones, which covered the entire length of the coding region of the SP-H antigen, were obtained. Polyclonal antibodies raised against fusion proteins generated from non-overlapping cDNA fragments stained the HeLa SP-H antigen in interphase and mitotic cells, and recognized a single 215 kDa band on immunoblots, as did the original SP-H antibody. Analysis of the nucleotide sequence revealed a 7,091 nucleotide sequence with an open reading frame of 6,345 nucleotides encoding a 2,115 amino acid polypeptide with a calculated molecular mass of 238,376 Da. The predicted amino acid sequence showed the protein to be composed of an alpha-helical domain, flanked by globular domains located at the amino and carboxy termini. The sequence contained five repeats of the hypothetical leucine zipper motif: one is in the N-terminal globular domain, and four are in the central alpha-helical stalk. Comparison with other sequences in the database shows that the SP-H antigen is identical to the NuMA protein reported by Yang et al. (1992) J. Cell Biol. 116, 1303–1317, but there are differences between the SP-H antigen and NuMA sequence reported by Compton et al. (1992) J. Cell Biol. 116, 1395–1408. cDNA inserts of the truncated SP-H antigen were expressed in both insect Sf9 cells and in cultured mammalian cells. The recombinant protein corresponding to the C-terminal half of the protein was restricted to the nucleus, whereas the N-terminal half of the protein was localized in the cytoplasm, suggesting the presence of a nuclear translocation signal(s) in the C-terminal domain. The C-terminal polypeptide expressed in mitotic COS cells was shown to specifically localize at the spindle pole. Microtubule-binding assays using in vitro transcribed/translated polypeptide products from different domains of the SP-H antigen further suggested that the SP-H antigen interacts with microtubules through the globular domain at the C-terminus.


Blood ◽  
1991 ◽  
Vol 78 (7) ◽  
pp. 1826-1833 ◽  
Author(s):  
LE Toothaker ◽  
DA Gonzalez ◽  
N Tung ◽  
RS Lemons ◽  
MM Le Beau ◽  
...  

Abstract We have isolated 5′ cDNA clones encoding a member of the cellular myosin heavy chain gene family from human leukocytes. The predicted amino acid sequence shows 93% identity to a chicken cellular myosin heavy chain, 76% to chicken smooth muscle, and 40% to human sarcomeric myosin heavy chain. The mRNA is expressed as a 7.4- to 7.9-kb doublet in many nonmuscle cells, and is upregulated in myeloid cell lines on induction from a proliferating to a differentiated state. Antisera raised against a peptide made from the predicted amino acid sequence specifically reacts with a 224-Kd polypeptide in leukocyte cell lines, and the protein is also upregulated during the induction of monocytic and granulocytic differentiation in these cells. The gene for this cellular myosin heavy chain maps to chromosome 22, bands q12.3-q13.1, demonstrating that it is not located in the previously described sarcomeric gene clusters on chromosomes 14 and 17. This cellular myosin heavy chain may be a major contractile protein responsible for movement in myeloid cell lines because no mRNA for sarcomeric myosin heavy chain is detected in these cells.


1990 ◽  
Vol 126 (1) ◽  
pp. 141-149 ◽  
Author(s):  
W. C. Warren ◽  
R. Liang ◽  
G. G. Krivi ◽  
N. R. Siegel ◽  
R. V. Anthony

ABSTRACT Discrepancies exist in the reported purity and biological activity of ovine placental lactogen (oPL), and little structural characterization has been reported. Ovine PL was purified from fetal cotyledonary tissue (day 100 of gestation) by monitoring activity with a recombinant bovine GH (bGH) liver radioreceptor assay. Two hundred grams of tissue yielded 4·2 mg of oPL, with an ∼ 1000-fold purification of oPL specific activity following initial tissue extraction. The oPL was radioiodinated and used in an ovine fetal liver (day 100 of gestation) radioreceptor assay to examine competitive displacement of oPL, ovine GH (oGH) and ovine prolactin (oPRL). The potency of oPL (ED50 = 0·18 nmol/l; ED50 is the quantity of ligand necessary to displace 50% of specifically bound 125I-labelled oPL) was greater than that of oGH (ED50 = 4·1 nmol/l) and oPRL (ED50 = 1·1 μmol/l) in competing for 125I-labelled oPL-binding sites. Attempts to sequence the NH2 terminus of oPL by vapour-phase sequencing indicated that the NH2 terminus was blocked. Purified oPL was subjected to trypsin and CnBr digestion, and two CnBr and six tryptic peptides were sequenced. The peptide sequences were compared with other PLs, oPRL and bGH for sequence similarity, and found to be most similar to bovine PL (bPL; 68% overall identity) and oPRL (47% overall identity). Complementary DNA (cDNA) clones were isolated for oPL by screening a λZAP cDNA library with a cDNA coding for bPL. Three cDNAs were nucleotide sequenced, and their combined sequence included 41 nucleotides of 5'-untranslated region, the complete coding region of pre-oPL (708 nucleotides) and a portion of the 3' untranslated region (158 nucleotides). The predicted amino acid sequence derived from the nucleotide sequence confirmed homology to bPL (67%) and oPRL (48%). Little amino acid sequence existed with other PLs (≤29%) or GH proteins (≤27%). These results suggest that oPL and oGH are more biologically similar in their ability to compete for fetal liver binding sites, but that oPL is structurally more similar to oPRL. Elucidation of exact structure–function relationships for oPL will, however, require further investigation. Journal of Endocrinology (1990) 126, 141–149


Blood ◽  
1991 ◽  
Vol 78 (7) ◽  
pp. 1826-1833
Author(s):  
LE Toothaker ◽  
DA Gonzalez ◽  
N Tung ◽  
RS Lemons ◽  
MM Le Beau ◽  
...  

We have isolated 5′ cDNA clones encoding a member of the cellular myosin heavy chain gene family from human leukocytes. The predicted amino acid sequence shows 93% identity to a chicken cellular myosin heavy chain, 76% to chicken smooth muscle, and 40% to human sarcomeric myosin heavy chain. The mRNA is expressed as a 7.4- to 7.9-kb doublet in many nonmuscle cells, and is upregulated in myeloid cell lines on induction from a proliferating to a differentiated state. Antisera raised against a peptide made from the predicted amino acid sequence specifically reacts with a 224-Kd polypeptide in leukocyte cell lines, and the protein is also upregulated during the induction of monocytic and granulocytic differentiation in these cells. The gene for this cellular myosin heavy chain maps to chromosome 22, bands q12.3-q13.1, demonstrating that it is not located in the previously described sarcomeric gene clusters on chromosomes 14 and 17. This cellular myosin heavy chain may be a major contractile protein responsible for movement in myeloid cell lines because no mRNA for sarcomeric myosin heavy chain is detected in these cells.


1984 ◽  
Vol 4 (12) ◽  
pp. 2686-2696 ◽  
Author(s):  
J Youngblom ◽  
J A Schloss ◽  
C D Silflow

The two beta-tubulin genes of the unicellular green alga Chlamydomonas reinhardtii are expressed coordinately after deflagellation and produce two transcripts of 2.1 and 2.0 kilobases. Full-length cDNA clones corresponding to the transcript of each gene were isolated. DNA sequences were obtained from the cDNA clones and from cloned tubulin gene fragments. Both genes contained 1,332 base pairs of coding sequence, with only 19 nucleotide differences between the genes. Because all the differences occurred at the third base position of a codon and did not change the predicted amino acid sequence, we concluded that both beta-tubulin genes code for the same protein of 443 amino acids. The predicted amino acid sequence is 89 and 72% homologous with beta-tubulins from chicken and yeast cells, respectively. Each gene had three intervening sequences, which occurred at identical positions. Although the first two intervening sequences were not conserved between the two genes, the nucleotide sequence of the third intervening sequence was 89% conserved between the genes. The codon usage in the tubulin genes of C. reinhardtii was very biased: only 37 different codons were used. Striking differences occurred between the codons used in these nuclear genes and C. reinhardtii chloroplast genes.


1989 ◽  
Vol 109 (6) ◽  
pp. 3039-3052 ◽  
Author(s):  
G A Oyler ◽  
G A Higgins ◽  
R A Hart ◽  
E Battenberg ◽  
M Billingsley ◽  
...  

cDNA clones of a neuronal-specific mRNA encoding a novel 25-kD synaptosomal protein, SNAP-25, that is widely, but differentially expressed by diverse neuronal subpopulations of the mammalian nervous system have been isolated and characterized. The sequence of the SNAP-25 cDNA revealed a single open reading frame that encodes a primary translation product of 206 amino acids. Antisera elicited against a 12-amino acid peptide, corresponding to the carboxy-terminal residues of the predicted polypeptide sequence, recognized a single 25-kD protein that is associated with synaptosomal fractions of hippocampal preparations. The SNAP-25 polypeptide remains associated with synaptosomal membrane components after hypoosmotic lysis and is released by nonionic detergent but not high salt extraction. Although the SNAP-25 polypeptide lacks a hydrophobic stretch of residues compatible with a transmembrane region, the amino terminus may form an amphiphilic helix that may facilitate alignment with membranes. The predicted amino acid sequence also includes a cluster of four closely spaced cysteine residues, similar to the metal binding domains of some metalloproteins, suggesting that the SNAP-25 polypeptide may have the potential to coordinately bind metal ions. Consistent with the protein fractionation, light and electron microscopic immunocytochemistry indicated that SNAP-25 is located within the presynaptic terminals of hippocampal mossy fibers and the inner molecular layer of the dentate gyrus. The mRNA was found to be enriched within neurons of the neocortex, hippocampus, piriform cortex, anterior thalamic nuclei, pontine nuclei, and granule cells of the cerebellum. The distribution of the SNAP-25 mRNA and the association of the protein with presynaptic elements suggest that SNAP-25 may play an important role in the synaptic function of specific neuronal systems.


1993 ◽  
Vol 13 (3) ◽  
pp. 1385-1391
Author(s):  
H Watanabe ◽  
J Sawada ◽  
K Yano ◽  
K Yamaguchi ◽  
M Goto ◽  
...  

E4TF1 was originally identified as one of the transcription factors responsible for adenovirus E4 gene transcription. It is composed of two subunits, a DNA binding protein with a molecular mass of 60 kDa and a 53-kDa transcription-activating protein. Heterodimerization of these two subunits is essential for the protein to function as a transcription factor. In this study, we identified a new E4TF1 subunit, designated E4TF1-47, which has no DNA binding activity but can associate with E4TF1-60. We then cloned the cDNAs for each of the E4TF1 subunits. E4TF1 was purified, and the partial amino acid sequence of each subunit was determined. The predicted amino acid sequence of each cDNA clone revealed that E4TF1-60 had an ETS domain, which is a DNA binding domain common to ets-related transcription factors. E4TF1-53 had four tandemly repeated notch-ankyrin motifs. The putative cDNA of E4TF1-47 coded almost the same amino acid sequences as E4TF1-53. Three hundred and thirty-two amino acids of the N termini of E4TF1-47 and -53 were identical except for one amino acid insertion in E4TF1-53, and they differ from each other at the C terminus. These three recombinant cDNA clones were expressed in Escherichia coli, and the proteins behaved in the same manner as purified proteins in a gel retardation assay. Nucleotide and predicted amino acid sequences were highly homologous to GABP-alpha and -beta, which is further supported by the observation that GABP-specific antibody can recognize human E4TF1.


1988 ◽  
Vol 254 (3) ◽  
pp. 743-750 ◽  
Author(s):  
C G Tate ◽  
M J A Tanner

We have isolated almost full-length cDNA clones corresponding to human erythrocyte membrane sialoglycoproteins alpha (glycophorin A) and delta (glycophorin B). The predicted amino acid sequence of delta differs at two amino acid residues from the sequence determined by peptide sequencing. The sialoglycoprotein delta clone we have isolated contains an interrupting sequence within the region that gives rise to the cleaved N-terminal leader sequence for the protein and represents a product that is unlikely to be inserted into the erythrocyte membrane. Comparison of the cDNA sequences of alpha and delta shows very strong homology at the DNA level within the coding regions. The two mRNA sequences are closely related and differ by a number of clearly defined insertions and deletions.


1999 ◽  
Vol 337 (3) ◽  
pp. 425-431 ◽  
Author(s):  
Tea LANIŠNIK RIŽNER ◽  
Gabriele MOELLER ◽  
Hubert H. THOLE ◽  
Marija ŽAKELJ-MAVRIČ ◽  
Jerzy ADAMSKI

17β-Hydroxysteroid dehydrogenase (17β-HSD) from the filamentous fungus Cochliobolus lunatus (17β-HSDcl) catalyses the reduction of steroids and of several o- and p-quinones. After purification of the enzyme, its partial amino acid sequence was determined. A PCR fragment amplified with primers derived from peptide sequences was generated for screening the Coch. lunatus cDNA library. Three independent full-length cDNA clones were isolated and sequenced, revealing an 810-bp open reading frame encoding a 270-amino-acid protein. After expression in Escherichia coli and purification to homogeneity, the enzyme was found to be active towards androstenedione and menadione, and was able to form dimers of Mr 60000. The amino acid sequence of the novel 17β-HSD demonstrated high homology with fungal carbonyl reductases, such as versicolorin reductase from Emericella nidulans (Aspergillus nidulans; VerA) and Asp. parasiticus (Ver1), polyhydroxynaphthalene reductase from Magnaporthe grisea, the product of the Brn1 gene from Coch. heterostrophus and a reductase from Colletotrichum lagenarium, which are all members of the short-chain dehydrogenase/reductase superfamily. 17β-HSDcl is the first discovered fungal 17β-hydroxysteroid dehydrogenase belonging to this family. The primary structure of this enzyme may therefore help to elucidate the evolutionary history of steroid dehydrogenases.


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