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1.
Masatoshi Mita Tomohiro Osugi Shin Matsubara Tsuyoshi Kawada Honoo Satake Hidekazu Katayama 《Molecular reproduction and development》2021,88(1):34-42
A relaxin‐like gonad‐stimulating peptide (RGP) in starfish was the first identified invertebrate gonadotropin responsible for final gamete maturation. An RGP ortholog was newly identified from Astropecten scoparius of the order Paxillosida. The A. scoparius RGP (AscRGP) precursor is encoded by a 354 base pair open reading frame and is a 118 amino acid (aa) protein consisting of a signal peptide (26 aa), B‐chain (21 aa), C‐peptide (47 aa), and A‐chain (24 aa). There are three putative processing sites (Lys‐Arg) between the B‐chain and C‐peptide, between the C‐peptide and A‐chain, and within the C‐peptide. This structural organization revealed that the mature AscRGP is composed of A‐ and B‐chains with two interchain disulfide bonds and one intrachain disulfide bond. The C‐terminal residues of the B‐chain are Gln‐Gly‐Arg, which is a potential substrate for formation of an amidated C‐terminal Gln residue. Non‐amidated (AscRGP‐GR) and amidated (AscRGP‐NH2) peptides were chemically synthesized and their effect on gamete shedding activity was examined using A. scoparius ovaries. Both AscRGP‐GR and AscRGP‐NH2 induced oocyte maturation and ovulation in similar dose‐dependent manners. This is the first report on a C‐terminally amidated functional RGP. Collectively, these results suggest that AscRGP‐GR and AscRGP‐NH2 act as a natural gonadotropic hormone in A. scoparius. 相似文献
2.
Masatoshi Mita Ikuo Yasumasu Yoshitaka Nagahama Mineo Saneyoshi 《Development, growth & differentiation》1996,38(4):413-418
The resumption of meiosis in starfish oocytes is induced by 1-methyladenine (1-MeA), which is produced by ovarian foilicle cells under the influence of a gonad-stimulating substance (GSS). It has been reported that the 1-MeA produced is newly synthesized via a process of methylation, rather than being pre-stored within follicle cells or a breakdown product of some 1-MeA-containing substance. The present study examined a possible substrate for 1-MeA biosynthesis stored in follicle cells of the starfish Asterina pectinifera . Analyses using high-performance liquid chromatography indicated a large source of ATP among the adenine-related compounds in these follicle cells. When follicle cells were incubated in seawater in the presence of GSS, 1-MeA production was stimulated significantly. GSS also caused a reduction in intracellular levels of ATP. There was no change in the levels of either ADP or AMP. The amount of ATP consumed under the influence of GSS was similar to the amount of 1-MeA produced. Methionine and selenomethionine enhanced both 1-MeA production and ATP consumption by GSS in follicle cells. In contrast, ethionine and selenoethionine, competitive inhibitors of methionine, inhibited these processes. These results suggest that ATP is a possible substrate in the biosynthesis of 1-MeA by starfish ovarian follicle cells. 相似文献
3.
MASATOSHI MITA 《Invertebrate reproduction & development.》2013,57(1-3):11-15
Summary Resumption of meiosis in starfish oocytes is induced by 1-methyladenine (1-MeAde) produced by ovarian follicle cells under the influence of a gonad-stimulating substance (GSS). With respect to 1-MeAde production by follicle cells of the starfish, Asterina pectinifera, (1) the action of GSS is initiated by a receptor mediated activation of G-proteins, resulting in the activation of adenylate cyclase and cyclic AMP (cAMP) formation; (2) 1-MeAde produced under the influence of GSS is not prestored within the follicle cells but is newly synthesized from a 1-MeAde precursor; (3) AMP plays an important role in the process of methylation during 1-MeAde biosynthesis induced by GSS. 相似文献
4.
The spatiotemporal expression pattern of gonad-stimulating substance-like peptide-containing polypeptide (GSSLP) in the sea cucumber Apostichopus japonicus was examined using immunochemistry. The GSSLP was detected in the gonads from shortly before the empirical breeding season (May and June) to July. On the basis of immunoblotting analysis, GSSLP showed considerable polymorphism among the organs examined in this study, particularly in the gonads, in which the polymorphism was associated with N-glycosylation and the formation of intra-molecular disulfide bonds. In the ovary, GSSLP was expressed from March to June and corresponded to two bands at 113 and 100 kDa under reducing conditions. In July, only the larger band weakly remained. In testis, GSSLP was detected first in April as two bands of 245 and 190 kDa under reducing conditions. The number of bands increased to five in June but decreased to three smeared bands in July. In the radial nerve and circumoral nerve ring, GSSLP corresponded to a single peptide of 170 kDa with little N-glycosylation and its expression level hardly changed throughout a year with no correlation with the breeding season. GSSLP was detected mainly in the morula cells in all the organs examined. In addition, GSSLP was detected in the follicle cells of the ovary and, for a brief period, in the jelly space, but never in the ooplasm. In testis, the morula cells were localized close to the invaginated inner epithelium, but never in the male gametes. In July animals, gonadal morula cells were rarely observed. 相似文献
5.
Yongbin Xu Chun‐Shan Quan Xiaoling Jin Xuanzhen Jin Jing Zhao Liming Jin Jin‐Sik Kim Jianyun Guo Shengdi Fan Nam‐Chul Ha 《Acta Crystallographica. Section F, Structural Biology Communications》2015,71(4):393-396
Prokaryotic 5′‐methylthioadenosine/S‐adenosylhomocysteine nucleosidase (MtaN) is a multifunctional enzyme that can hydrolyze S‐adenosyl‐L‐homocysteine (SAH) and S‐methyl‐5′‐thioadenosine (MTA) to give S‐ribosyl‐L‐homocysteine (SRH) and S‐methyl‐5′‐thioribose (MTR), respectively. This reaction plays a key role in several metabolic pathways, including biological methylation, polyamine biosynthesis, methionine recycling and bacterial quorum sensing. Structurally, MtaN belongs to the MtnN subfamily of the purine nucleoside phosphorylase (PNP)/uridine phosphorylase (UDP) phosphorylase family. Aeromonas hydrophila has two MtnN subfamily proteins: MtaN‐1, a periplasmic protein with an N‐terminal signal sequence, and MtaN‐2, a cytosolic protein. In this study, MtaN‐1 from Aeromonas hydrophila was successfully expressed and purified using Ni–NTA affinity, Q anion‐exchange and gel‐filtration chromatography. Crystals of the protein in complex with the substrate SAH were obtained and diffracted to a resolution of 1.4 Å. The crystals belonged to the trigonal space group P3121 or P3221, with unit‐cell parameters a = b = 102.7, c = 118.8 Å. The asymmetric unit contained two molecules of MtaN‐1 complexed with SAH. 相似文献
6.
Methionine restriction (MetR) extends lifespan across different species and exerts beneficial effects on metabolic health and inflammatory responses. In contrast, certain cancer cells exhibit methionine auxotrophy that can be exploited for therapeutic treatment, as decreasing dietary methionine selectively suppresses tumor growth. Thus, MetR represents an intervention that can extend lifespan with a complementary effect of delaying tumor growth. Beyond its function in protein synthesis, methionine feeds into complex metabolic pathways including the methionine cycle, the transsulfuration pathway, and polyamine biosynthesis. Manipulation of each of these branches extends lifespan; however, the interplay between MetR and these branches during regulation of lifespan is not well understood. In addition, a potential mechanism linking the activity of methionine metabolism and lifespan is regulation of production of the methyl donor S‐adenosylmethionine, which, after transferring its methyl group, is converted to S‐adenosylhomocysteine. Methylation regulates a wide range of processes, including those thought to be responsible for lifespan extension by MetR. Although the exact mechanisms of lifespan extension by MetR or methionine metabolism reprogramming are unknown, it may act via reducing the rate of translation, modifying gene expression, inducing a hormetic response, modulating autophagy, or inducing mitochondrial function, antioxidant defense, or other metabolic processes. Here, we review the mechanisms of lifespan extension by MetR and different branches of methionine metabolism in different species and the potential for exploiting the regulation of methyltransferases to delay aging. 相似文献
7.
Charles Packianathan Jitesh K. Pillai Ahmed Riaz Palani Kandavelu Banumathi Sankaran Barry P. Rosen 《Acta Crystallographica. Section F, Structural Biology Communications》2014,70(10):1385-1388
Arsenic is one the most toxic environmental substances. Arsenic is ubiquitous in water, soil and food, and ranks first on the Environmental Protection Agency's Superfund Priority List of Hazardous Substances. Arsenic(III) S‐adenosylmethionine methyltransferases (AS3MT in animals and ArsM in microbes) are key enzymes of arsenic biotransformation, catalyzing the methylation of inorganic arsenite to give methyl, dimethyl and trimethyl products. Arsenic methyltransferases are found in members of every kingdom from bacteria to humans (EC 2.1.1.137). In the human liver, hAS3MT converts inorganic arsenic into more toxic and carcinogenic forms. CrArsM, an ortholog of hAS3MT from the eukaryotic green alga Chlamydomonas reinhardtii, was purified by chemically synthesizing the gene and expressing it in Escherichia coli. Synthetic purified CrArsM was crystallized in an unliganded form. Crystals were obtained by the hanging‐drop vapor‐diffusion method. The crystals belonged to space group R3:H, with unit‐cell parameters a = b = 157.8, c = 95.4 Å, γ = 120° and two molecules in the asymmetric unit. Complete data sets were collected and processed to a resolution of 2.40 Å. 相似文献
8.
Neelakshi Gohain Linda S. Thomashow Dmitri V. Mavrodi Wulf Blankenfeldt 《Acta Crystallographica. Section F, Structural Biology Communications》2006,62(9):887-890
Pyocyanin, phenazine‐1‐carboxylic acid and more than 70 related compounds collectively known as phenazines are produced by various species of Pseudomonas, including the fluorescent pseudomonad P. aeruginosa, a Gram‐negative opportunistic pathogen in humans and animals. P. aeruginosa synthesizes a characteristic blue water‐soluble compound called pyocyanin (1‐hydroxy‐5‐methyl‐phenazine). Two enzymes designated PhzM and PhzS are involved in the terminal steps of its synthesis and very little is known about these enzymes. In this study, PhzM, a dimeric S‐adenosylmethionine‐dependent methyltransferase, was purified and crystallized from PEG 3350/sodium cacodylate/sodium citrate pH 6.5. The crystals belong to space group P1, with unit‐cell parameters a = 46.1, b = 61.8, c = 69.6 Å, α = 96.3, β = 106.6, γ = 106.9°. They contain one dimer in the asymmetric unit and diffract to a resolution of 1.8 Å. Anomalous data to 2.3 Å resolution have been collected from seleno‐l ‐methionine‐labelled PhzM. 相似文献
9.
Jiraporn Panmanee Svetlana V. Antonyuk S. Samar Hasnain 《Acta Crystallographica. Section D, Structural Biology》2020,76(6):594-607
Methionine adenosyltransferase (MAT) deficiency, characterized by isolated persistent hypermethioninemia (IPH), is caused by mutations in the MAT1A gene encoding MATαl, one of the major hepatic enzymes. Most of the associated hypermethioninemic conditions are inherited as autosomal recessive traits; however, dominant inheritance of hypermethioninemia is caused by an Arg264His (R264H) mutation. This mutation has been confirmed in a screening programme of newborns as the most common mutation in babies with IPH. Arg264 makes an inter‐subunit salt bridge located at the dimer interface where the active site assembles. Here, it is demonstrated that the R264H mutation results in greatly reduced MAT activity, while retaining its ability to dimerize, indicating that the lower activity arises from alteration at the active site. The first crystallographic structure of the apo form of the wild‐type MATαl enzyme is provided, which shows a tetrameric assembly in which two compact dimers combine to form a catalytic tetramer. In contrast, the crystal structure of the MATαl R264H mutant reveals a weaker dimeric assembly, suggesting that the mutation lowers the affinity for dimer–dimer interaction. The formation of a hetero‐oligomer with the regulatory MATβV1 subunit or incubation with a quinolone‐based compound (SCR0911) results in the near‐full recovery of the enzymatic activity of the pathogenic mutation R264H, opening a clear avenue for a therapeutic solution based on chemical interventions that help to correct the defect of the enzyme in its ability to metabolize methionine. 相似文献
10.
Zhenfei Guo Jiali Tan Chunliu Zhuo Congying Wang Bin Xiang Zengyu Wang 《Plant biotechnology journal》2014,12(5):601-612
11.
Sečkutė J McCloskey DE Thomas HJ Secrist JA Pegg AE Ealick SE 《Protein science : a publication of the Protein Society》2011,20(11):1836-1844
Aminopropyltransferases are essential enzymes that form polyamines in eukaryotic and most prokaryotic cells. Spermidine synthase (SpdS) is one of the most well‐studied enzymes in this biosynthetic pathway. The enzyme uses decarboxylated S‐adenosylmethionine and a short‐chain polyamine (putrescine) to make a medium‐chain polyamine (spermidine) and 5′‐deoxy‐5′‐methylthioadenosine as a byproduct. Here, we report a new spermidine synthase inhibitor, decarboxylated S‐adenosylhomocysteine (dcSAH). The inhibitor was synthesized, and dose‐dependent inhibition of human, Thermatoga maritima, and Plasmodium falciparum spermidine synthases, as well as functionally homologous human spermine synthase, was determined. The human SpdS/dcSAH complex structure was determined by X‐ray crystallography at 2.0 Å resolution and showed consistent active site positioning and coordination with previously known structures. Isothermal calorimetry binding assays confirmed inhibitor binding to human SpdS with Kd of 1.1 ± 0.3 μM in the absence of putrescine and 3.2 ± 0.1 μM in the presence of putrescine. These results indicate a potential for further inhibitor development based on the dcSAH scaffold. 相似文献
12.
Abstract The aim of this work was to determine whether the neurogenic mechanisms which trigger LH release during the critical period in the afternoon of proestrus could be revealed during the diestrous period of the cycle. 相似文献
13.
During evaluation of follicle-stimulating hormone-beta (FSHB) expression in anterior pituitary glands by an RNase protection assay (RPA), the expected fragment of 205 nucleotides at positions 759-963 was not detected in one boar that had moderate plasma and pituitary FSH concentrations. After subcloning and sequencing, mRNA from this boar lacked an 11-bp fragment (5'-CATTTGGAAAC-3') at nucleotide positions 807-817 of the 3'-untranslated region (3'-UTR, D allele). Wild-type FSHB (WT allele) was present in pituitary RNA and genomic DNA in both Meishan (MS) and White Composite (WC) pigs; whereas the D allele was present only in MS pigs (P < 0.01; 5/6 MS vs. 0/6 WC). Also, we found the D allele in five other Chinese breeds but absent in ten American Landrace, 11 Yorkshire and 17 Berkshire pigs. Additionally, the D allele had one silent nucleotide change in the coding region plus six, single nucleotide changes in the 3'-UTR. 相似文献
14.
Aims: S‐adenosyl‐l ‐methionine (SAM) is an important biochemical molecule with great potential in the pharmacological and chemotherapeutic fields. In this study, our aims were to enhance SAM production in Saccharomyces cerevisiae. Methods and Results: Through spaceflight culture, a SAM‐accumulating strain, S. cerevisiae H5M147, was isolated and found to produce 86·89% more SAM than its ground control strain H5. Amplified fragment length polymorphism (AFLP) analysis demonstrated that there were genetic variations between strain H5M147 and its ground control. Through recombinant DNA technology, the heterologous gene encoding methionine adenosyltransferase was integrated into the genome of strain H5M147. The recombinant strain H5MR83 was selected because its SAM production was increased by 42·98% when compared to strain H5M147. Furthermore, cultivation conditions were optimized using the one‐factor‐at‐a‐time and Taguchi methods. Under optimal conditions, strain H5MR83 yielded 7·76 g l?1 of SAM in shake flask, an increase of 536·07% when compared to the strain H5. Furthermore, 9·64 g l?1 of SAM was produced in fermenter cultivation. Conclusions: A new SAM‐accumulating strain, S. cerevisiae H5MR83, was obtained through spaceflight culture and genetic modification. Under optimal conditions, SAM production was increased to a relative high level in our study. Significance and Impact of the Study: Through comprehensive application of multiple methods including spaceflight culture, genetic modification and optimizing cultivation, the yield of SAM could be increased by 6·4 times compared to that in the control strain H5. The obtained S. cerevisiae H5MR83 produced 7·76 g l?1 of SAM in the flask cultures, a significant improvement on previously reported results. The SAM production period with S. cerevisiae H5MR83 was 84 h, which is shorter than previously reported results. Saccharomyces cerevisiae H5MR83 has considerable potential for use in industrial applications. 相似文献
15.
In addition to bone, the dentin‐pulp complex is also influenced by menopause, showing a decreased regenerative capacity. High levels of follicle‐stimulating hormone (FSH) during menopause could directly regulate bone metabolism. Here, the role of FSH in the odontogenic differentiation of the dentin‐pulp complex was investigated. Dental pulp stem cells (DPSCs) were isolated. CCK‐8 assays, cell apoptosis assays, Western blotting (WB), real‐time RT‐PCR, alkaline phosphatase activity assays, and Alizarin Red S staining were used to clarify the effects of FSH on the proliferation, apoptosis and odontogenic differentiation of the DPSCs. MAPK pathway‐related factors were explored by WB assays. FSH and its inhibitor were used in OVX rats combined with a direct pulp‐capping model. HE and immunohistochemistry were used to detect reparative dentin formation and related features. The results indicated that FSH significantly decreased the odontogenic differentiation of the DPSCs without affecting cell proliferation and apoptosis. Moreover, FSH significantly activated the JNK signalling pathway, and JNK inhibitor partly rescued the inhibitory effect of FSH on DPSC differentiation. In vivo, FSH treatment attenuated the dentin bridge formation and mineralization‐related protein expression in the OVX rats. Our findings indicated that FSH reduced the odontogenic capacity of the DPSCs and was involved in reparative dentinogenesis during menopause. 相似文献
16.
Nathan A. Delvaux James B. Thoden Hazel M. Holden 《Protein science : a publication of the Protein Society》2015,24(10):1593-1599
Kedarcidin, produced by Streptoalloteichus sp. ATCC 53650, is a fascinating chromoprotein of 114 amino acid residues that displays both antibiotic and anticancer activity. The chromophore responsible for its chemotherapeutic activity is an ansa‐bridged enediyne with two attached sugars, l ‐mycarose, and l ‐kedarosamine. The biosynthesis of l ‐kedarosamine, a highly unusual trideoxysugar, is beginning to be revealed through bioinformatics approaches. One of the enzymes putatively involved in the production of this carbohydrate is referred to as KedS8. It has been proposed that KedS8 is an N‐methyltransferase that utilizes S‐adenosylmethionine as the methyl donor and a dTDP‐linked C‐4′ amino sugar as the substrate. Here we describe the three‐dimensional architecture of KedS8 in complex with S‐adenosylhomocysteine. The structure was solved to 2.0 Å resolution and refined to an overall R‐factor of 17.1%. Unlike that observed for other sugar N‐methyltransferases, KedS8 adopts a novel tetrameric quaternary structure due to the swapping of β‐strands at the N‐termini of its subunits. The structure presented here represents the first example of an N‐methyltransferase that functions on C‐4′ rather than C‐3′ amino sugars. 相似文献
17.
Hideki Takahashi Shu Hase Yoshinori Kanayama Shigehito Takenaka 《Journal of Phytopathology》2010,158(2):132-136
The expression of LeATL6, which encodes RING‐H2 zinc finger ubiquitin‐protein ligase E3, is highly induced in tomato roots treated with the elicitin‐like cell wall protein fraction (CWP) from the non‐pathogenic oomycete Pythium oligandrum, which enhances resistance to pathogens through a jasmonic acid (JA)‐dependent signalling pathway. In this study, the role of LeATL6 for CWP‐induced defence response was further analysed. To screen the putative target protein of LeATL6 for the CWP‐induced defence mechanism in tomato, we used a yeast two‐hybrid system to screen five clones encoding a protein that interacts with LeATL6. Four clones had a function associated with the ubiquitin‐proteasome system. Another positive clone encoded a protein sharing homology with S‐adenosylmethionine decarboxylase (SAMDC). In CWP‐treated tomato roots, SAMDC activity was clearly suppressed. Thus, the interaction of SAMDC with LeATL6 and the decreased SAMDC activity may be associated with JA‐dependent induced resistance in tomato treated with P. oligandrum. 相似文献
18.
Clemens Grimm Gerhard Klebe Ralf Ficner Klaus Reuter 《Acta Crystallographica. Section D, Structural Biology》2000,56(4):484-488
The genes encoding the tRNA‐modifying enzyme S‐adenosylmethionine:tRNA ribosyl transferase/isomerase (QueA) from 12 eubacterial sources were overexpressed in Escherichia coli and the resulting products were purified to homogeneity and subjected to crystallization trials. Using the hanging‐drop vapour‐diffusion method, crystals suitable for X‐ray diffraction experiments were only obtained for the queA gene product from Bacillus subtilis. The crystals belong to the space group P422, with unit‐cell parameters a = b = 100.7, c = 150.9 Å. Using highly focused synchrotron radiation from the EMBL/ESRF beamline ID13 (Grenoble, France), diffraction to at least 3.2 Å could be achieved. A selenomethionyl derivative of the protein was prepared and crystallized for future multiwavelength anomalous diffraction (MAD) experiments. 相似文献
19.
Larry D. Anderson Sarah Lipford Stone Cornelia P. Channing 《Molecular reproduction and development》1985,12(2):119-130
This study examines the influence of follicular maturation as well as the role of various hormones upon the secretion of an oocyte maturation inhibitor (OMI) from porcine granulosa cells incubated in vitro. The results demonstrate that the OMI substance, secreted into the media by granulosa cells, is present in a low molecular-weight fraction (< 10,000 daltons) similar to that found in follicular fluid of porcine antral follicles. Also, as follicular development progresses, the granulosa cells lose their ability to secrete OMI. More importantly, hormones appear to regulate OMI secretion: FSH stimulates OMI secretion and androgens inhibit OMI secretion. These data provide evidence for the proposal of the following hypothesis concerning hormonal regulation of oocyte, meiosis by OMI in the porcine follicle: Whether the oocyte resumes meiosis, either during atresia or ovulation, is dependent upon the proper milieu of gonadotropins, cyclic-AMP, and steroids within the microenvironment of the follicular compartment. The cellular interactions of these hormones, particularly FSH and androgens, control the amount of OMI (and possibly other intrafollicular factors) secreted in the follicle, which may be involved in either maintaining the immature state or permitting meiotic maturation. 相似文献
20.
Regina Celia Rodrigues da Paz William Frederick Swanson Eduardo Antunes Dias Cristina Harumi Adania Valquíria Hipplito Barnabe Renato Campanarut Barnabe 《Zoo biology》2005,24(3):247-260
Exogenous gonadotropins frequently are used to stimulate ovarian follicular growth and ovulation in mammalian species, including felids. However, repeated exogenous gonadotropin treatment can result in decreased ovarian responsiveness due to antibody formation. In this study, our objectives were to assess the effectiveness of alternating gonadotropin regimens on ovarian responses in ocelots and tigrinas, and investigate the humoral immune responses to these gonadotropins in each species. Females were treated four to six times with alternating equine chorionic gonadotropin (eCG)/human chorionic gonadotropin (hCG) and porcine follicle stimulating hormone (pFSH)/luteinizing hormone (pLH) regimens at 4‐month intervals. With each treatment, the females were evaluated laparoscopically to assess ovarian follicular development and recover oocytes from mature follicles. Blood was collected before each treatment and at laparoscopy. Overall, the ocelots averaged more (P<0.05) follicles and corpus luteum (CL) (6.8±0.8; mean±SEM) per stimulation than the tigrinas (2.3±0.4), but the percentage of mature oocytes (mean range=54–55%) did not differ (P<0.05). Within species, both gonadotropin regimens were equally effective (P>0.05) in inducing follicular growth and oocyte maturation. The total number of ovarian structures and oocyte maturation percentages did not decrease (P<0.05) in either species with sequential stimulations. Although the percentage of blood samples containing anti‐gonadotropin immunoglobulins increased (P<0.05) with sequential treatment, the presence of positive titers did not cause a decrease (P<0.05) in ovarian responsiveness. In summary, the female ocelots and tigrinas continued to respond to these alternating ovarian stimulation protocols after repeated use, despite the formation of anti‐gonadotropin antibodies in some of the females. These findings suggest that the use of alternating gonadotropin regimens may permit more intensive reproductive management of these endangered cat species for conservation. Zoo Biol 00:1–14, 2005. © 2005 Wiley‐Liss, Inc. 相似文献