The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Eileen M Handberg - One of the best experts on this subject based on the ideXlab platform.
-
cardiac magnetic resonance myocardial perfusion reserve index is reduced in women with coronary microvascular dysfunction
Circulation-cardiovascular Imaging, 2015Co-Authors: Louise Thomson, Janet Wei, Megha Agarwal, Afsaneh Haftbaradaran, Chrisandra Shufelt, Puja K Mehta, Edward Gill, Delia B Johnson, Tanya S Kenkre, Eileen M HandbergAbstract:Background—Women with signs and symptoms of ischemia and no obstructive coronary artery disease often have coronary microvascular dysfunction (CMD), diagnosed by invasive coronary reactivity testin...
-
cardiac magnetic resonance myocardial perfusion reserve index is reduced in women with coronary microvascular dysfunction a national heart lung and blood institute sponsored study from the women s ischemia syndrome evaluation
Circulation-cardiovascular Imaging, 2015Co-Authors: Louise Thomson, Janet Wei, Megha Agarwal, Afsaneh Haftbaradaran, Chrisandra Shufelt, Puja K Mehta, Edward Gill, Delia B Johnson, Tanya S Kenkre, Eileen M HandbergAbstract:Background—Women with signs and symptoms of ischemia and no obstructive coronary artery disease often have coronary microvascular dysfunction (CMD), diagnosed by invasive coronary reactivity testin...
Stephan Schneider - One of the best experts on this subject based on the ideXlab platform.
-
Additional file 1: of Taxon-specific expansion and loss of Tektins inform metazoan ciliary diversity
2019Co-Authors: Benjamin Bastin, Stephan SchneiderAbstract:Comprehensive table of the Tektin gene complement found in species included in this study (related to Table 1). The table shows all species examined in this study and their Tektin gene complement with the exception of some teleost fish removed for redundancy. Species are listed according to four groups: (1) nonbilaterians, (2) spiralians, (3) ecdysozoans, and (4) deuterostomes. The Tektin gene complement for each species is presented by total number of Tektin genes within their genome in the right column, as well as the number of homologs found for each of the four bilaterian classes: Tektin-2, Tektin-1, Tektin-4, and Tektin-3/5 (in spiralians: Tektin-3/5A and 3/5B, in vertebrates: Tektin-3 and -5). The Tektin gene complements for distinct inferred Last Common Ancestors (LCAs) are also shown. Gray boxes indicate metazoans that have maintained the ancestral Tektin gene complement inferred for their clade (nonbilaterians, spiralians, ecdysozoans, or deuterostomes). Blue boxes indicate metazoans that have experienced duplications of Tektin-3/5, but maintain single copies of Tektin-1, − 2 and − 4. Pink boxes indicate the vertebrates that have lost Tektin-5. Note that the four Tektin classes are bilaterian specific originating by ancient gene duplications from two nonbilaterian and one unicellular Tektin gene(s). * indicates partial sequence left out of final analysis. ** indicates highly divergent long branch sequences after initial analyses and left out of final analysis. Yellow circles indicate key clades as follows. Unicellular Eukaryotes and Nonbilaterian Metazoans table: E = Eukaryota, O = Opisthokonta, H = Holozoa, A = Apoikozoa, M = Metazoa. Spiralian table: S = Spiralia, G = Gnathifera, R = Rouphozoa, M = Mesozoa, L = Lophotrochozoa. Ecdysozoan table: E = Ecdysozoa, A = Arthropoda. Deuterostome table: D = Deuterostomia, C = Chordata. Tree structures are based on – Eukaryotes: Burki 2014, Janouskevec et al. 2017, Torruella et al. 2015, and Budd and Jensen 2017 [73–76]; Spiralia: Laumer et al. 2015 and Lu et al. 2017 [49, 77]; Ecdysozoa: Borner 2014 [78]. * = for alternative scenario of the bilaterian ancestor see Discussion. (PDF 223 kb
-
Additional file 7: of Taxon-specific expansion and loss of Tektins inform metazoan ciliary diversity
2019Co-Authors: Benjamin Bastin, Stephan SchneiderAbstract:Phylogenetic tree illustrating the Tektin gene diversity in spiralians. This phylogenetic analysis is focused on spiralian Tektins including the full complement of the greatly expanded and divergent Tektin gene complements of Platyhelminthes and the leech H. robusta. Both Bayesian and Maximum Likelihood analyses were performed using Mr. Bayes and RAxML, respectively. Bayesian tree is shown. Node support is shown for non-terminal nodes. Posterior probability values from Mr. Bayes are shown above each node and bootstrap values from RAxML are shown below each node. Diamonds indicate support less than 80%. An “X” under a node indicates this node was not recovered in the RAxML maximum likelihood tree. Tree was rooted with choanoflagellate Tektins. The planarian S. mediterranea (Sme) and the leech H. robusta (Hr) independently evolved an identical expanded Tektin gene complement of ten Tektin genes from the five ancestral spiralian Tektin genes. Some Tektins were subsequently lost in the parasitic Platyhelminthes. Platyhelminthes species are highlighted with boxes. S. mediterranea and H. robusta are highlighted with red text. Species abbreviations and accession numbers for each sequence are provided in Additional file 5. (PDF 689 kb
-
Additional file 3: of Taxon-specific expansion and loss of Tektins inform metazoan ciliary diversity
2019Co-Authors: Benjamin Bastin, Stephan SchneiderAbstract:Conservation and Divergence of Tektin proteins in bilaterians. Comparison of Tektin sequence conservation among selected species from spiralians (Mli, Cg, La, Pd), ecdysozoans (Tc, Bt, Dm, Pc, Sma), and deuterostomes (Hs, Gg, Bf, Sp, Sk). Percent identity shared at the amino acid level is given for each Tektin. Boxes are shaded according to degree of conservation with 30% identity or below being white, and 70% and above being the darkest blue. While spiralian and deuterostome exhibit high levels of sequence conservation at the amino acid level between Tektins of each class, ecdysozoans tend to have much lower sequence identity both when compared to spiralians and deuterostomes as well as when compared to other ecdysozoans. Exceptions are ecdysozoan Tektin-3/5 s that are generally higher conserved than other ecdysozoan Tektins belonging to the Tektin-1, − 2, and − 4 class. (PDF 628 kb
-
Additional file 9: of Taxon-specific expansion and loss of Tektins inform metazoan ciliary diversity
2019Co-Authors: Benjamin Bastin, Stephan SchneiderAbstract:Comparison of this study vs. Nevers et al. [50] and Amos [20]. Comparison of findings of this study to phylogenetic analysis data by Nevers et al. [50] and Amos [20]. Species examined in both this study and at least one of the previous two are shown with the number of each Tektin class, and total number of Tektins found in each study. As the Nevers et al. [50] study used presence/absence data, a ‘+’ indicates presence while ‘0’ represents absence. Totals for Nevers et al. [50] are based on assumption that a ‘+’ is equal to one homolog. * indicates that different species from the same genus are compared. ** indicates different species from the same order or family are compared. *** indicates at least one Tektin did not group with any of the five recognized Tektins. † indicates that Nevers et al. [50] identified additional Tektin homologs that our study was unable to find. †† indicates the special case of human Tektins reported in Amos [20] (see Discussion). Green background indicates the previous study found the same number of Tektins as our study but with one or more misclassified. Red background indicates that the previous study found a different number of Tektins than our study. (PDF 660 kb
-
Additional file 8: of Taxon-specific expansion and loss of Tektins inform metazoan ciliary diversity
2019Co-Authors: Benjamin Bastin, Stephan SchneiderAbstract:Phylogenetic tree illustrating the Tektin gene diversity in ecdysozoans. This phylogenetic analysis is focused on ecdysozoan Tektins. Both Bayesian and Maximum Likelihood analyses were performed using Mr. Bayes and RAxML, respectively. Bayesian tree is shown. Node support is shown for non-terminal nodes. Posterior probability values from Mr. Bayes are shown above each node and bootstrap values from RAxML are shown below each node. Diamonds indicate support less than 80%. An “X” under a node indicates this node was not recovered in the RAxML maximum likelihood tree. Tree was rooted with choanoflagellate Tektin. Species abbreviations and accession numbers for each sequence are provided in Additional file 5. (PDF 659 kb
Richard W. Linck - One of the best experts on this subject based on the ideXlab platform.
-
Tektin interactions and a model for molecular functions
Experimental Cell Research, 2006Co-Authors: Peter W Setter, Walter Steffen, Erika Malveydorn, R E Stephens, Richard W. LinckAbstract:Abstract Tektins from echinoderm flagella were analyzed for microheterogeneity, self-associations and association with tubulin, resulting in a general model of Tektin filament structure and function applicable to most eukaryotic cilia and flagella. Using a new antibody to Tektin consensus peptide RPNVELCRD, well-characterized chain-specific antibodies and quantitative gel densitometry, Tektins A, B and C were found to be present in equimolar amounts in Sarkosyl-urea-stable filaments. In addition, two isoforms of Tektin A are present in half-molar ratios to Tektins B and C. Cross-linking of AB filaments indicates in situ nearest neighbor associations of Tektin A1B and A2B heterodimers, -trimers, -tetramers and higher oligomers. Soluble purified Tektin C is cross-linked as homodimers, trimers and tetramers, but not higher oligomers. Tektin filaments associate with both loosely bound and tightly bound tubulin, and with the latter in a 1:1 molar ratio, implying a specific, periodic association of tightly bound tubulin along the Tektin axis. Similarly, in Tektin-containing Sarkosyl-stable protofilament ribbons, two polypeptides (∼67/73 kDa, homologues of rib72, efhc1 and efhc2) are present in equimolar ratios to each other and to individual Tektins, co-fractionating with loosely bound tubulin. These results suggest a super-coiled arrangement of Tektin filaments, the organization of which has important implications for the evolution, assembly and functions of cilia and flagella.
-
the spatial and temporal expression of tekt1 a mouse Tektin c homologue during spermatogenesis suggest that it is involved in the development of the sperm tail basal body and axoneme
European Journal of Cell Biology, 2000Co-Authors: Magnus Larsson, Richard W. Linck, Jan M. Norrander, Susanne Graslund, Eva Brundell, Stefan Stahl, Christer HoogAbstract:Tektins comprise a family of filament-forming proteins that are known to be coassembled with tubulins to form ciliary and flagellar microtubules. Recently we described the sequence of the first mammalian Tektin protein, Tekt1 (from mouse testis), which is most homologous with sea urchin Tektin C. We have now investigated the temporal and spatial expression of Tekt1 during mouse male germ cell development. By in situ hybridization analysis TEKT1 RNA expression is detected in spermatocytes and in round spermatids in the mouse testis. Immunofluorescence microscopy analysis with anti-Tekt1 antibodies showed no distinct labeling of any subcellular structure in spermatocytes, whereas in round spermatids anti-Tekt1 antibodies co-localize with anti-ANA antibodies to the centrosome. At a later stage, elongating spermatids display a larger area of anti-Tektl staining at their caudal ends; as spermiogenesis proceeds, the anti-Tekt1 staining disappears. Together with other evidence, these results provide the first intraspecies evidence that Tekt1 is transiently associated with the centrosome, and indicates that Tekt1 is one of several Tektins to participate in the nucleation of the flagellar axoneme of mature spermatozoa, perhaps being required to assemble the basal body.
-
transcriptional control of Tektin a mrna correlates with cilia development and length determination during sea urchin embryogenesis
Development, 1995Co-Authors: Jan M. Norrander, Richard W. Linck, R E StephensAbstract:Previous studies have shown that Tektin A, one of three integral filamentous protein components of outer doublet microtubules, is synthesized in sea urchins in an amount correlating to the length of embryonic cilia initially assembled or experimentally regenerated. To investigate further the molecular mechanism for the regulation of Tektin synthesis, Tektin cDNA clones were used to assess mRNA levels during ciliogenesis, zinc-induced animalization, deciliation-induced regeneration and theophylline-induced elongation. Possibly involved in centriole replication, low, near-constant levels of mRNA for all three Tektins are present in the unfertilized egg and during cleavage stages. Preceded by new synthesis of Tektin B and C mRNAs, Tektin A mRNA is up-regulated during ciliogenesis, but only Tektin A mRNA levels correlate directly with ciliary length in animalized embryos; the others augment larger, non-limiting pools of Tektins B and C. Tektin mRNAs decrease to steady-state levels after ciliogenesis, but are up-regulated again when the embryos are deciliated, correlating with the length of cilia to be deployed. In a species where a 3-fold ciliary length increase can be induced by theophylline treatment of zinc-arrested embryos, the mRNAs accumulate to proportionately higher levels during arrest but are not translated until induction, whereupon they decrease inversely with ciliary elongation. This suggests transcriptional control with respect to mRNA amounts but post-transcriptional control with respect to the expression of this phenotype.(ABSTRACT TRUNCATED AT 250 WORDS)
-
At least one of the protofilaments in flagellar microtubules is not composed of tubulin
Current Biology, 1995Co-Authors: Dana Nojima, Richard W. Linck, Edward H. EgelmanAbstract:Abstract Background: The core of the eukaryotic flagellum is the axoneme, a complex motile organelle composed of ∼200 different polypeptides. The most prominent components of the axoneme are the central pair and nine outer doublet microtubules. Each doublet microtubule contains an A and a B tubule; these are composed, respectively, of 13 and 10–11 protofilaments, all of which are thought to be made of tubulin. The mechanisms that control the assembly of the doublet microtubules and establish the periodic spacings of associated proteins, such as dynein arms and radial spokes, are unknown. Tektins, a set of microtubule-associated proteins, are present in the axoneme as stable filaments that remain after the extraction of doublet microtubules; they are localized near to where the B tubule attaches to the A tubule and near to the binding sites for radial spokes, inner dynein arms and nexin links. Tektin filaments may contribute in an interesting way to the structural properties of axonemes. Results We have fractionated doublet microtubules from sea urchin sperm flagella into ribbons of stable protofilaments, which can be shown to originate from the A tubule. Using cryo-electron microscopy, conventional electron microscopy, scanning transmission electron microscopy, three-dimensional reconstruction and kinesin decoration, we have found that one protofilament in the ribbon is not composed of tubulin. This protofilament is an integral protofilament of the A tubule wall, has less mass per unit length than tubulin and does not bind kinesin. Conclusion Contrary to what is generally assumed, at least one protofilament in the wall of the A tubule is not composed of tubulin. Our data suggest that this non-tubulin protofilament is primarily composed of Tektins, proteins that show some structural similarity to intermediate filament proteins. A 480 a axial periodicity within these ribbons, revealed by scanning transmission electron microscopy, can be related to the structure of Tektin, and may determine the large-scale structure of the axoneme in terms of the binding of dynein, nexin and radial spokes to the doublet microtubule.
-
Tektin b1 from ciliary microtubules primary structure as deduced from the cdna sequence and comparison with Tektin a1
Journal of Cell Science, 1993Co-Authors: Runtian Chen, Linda A. Amos, Catherine A Perrone, Richard W. LinckAbstract:Tektins are a class of proteins that form filamentous polymers in the walls of ciliary and flagellar microtubules, and they may also be present in centrioles, centrosomes and mitotic spindles. We report here the cloning and sequencing of a cDNA for ciliary Tektin B1. Comparison of the predicted amino acid sequence of Tektin B1 with the previously published sequence for Tektin A1 reveals several features that better define this class of proteins. Like Tektin A1, the central region of the Tektin B1 polypeptide chain is predicted to form a coiled-coil rod, consisting of four major alpha-helical regions that are separated by non-helical linkers. Between the central rod domains of Tektins A and B there is a 34%/20% amino acid sequence identity/similarity, including equivalent 50-residue segments containing 36 identities, and a high probability of long-range structural homology. The Tektin polypeptide chains are divided into two major segments that have significant sequence homology to each other, both within a given Tektin chain and between Tektins A and B, indicative of gene duplication events. The Tektins have a secondary structure and molecular design similar to, but a low primary sequence homology with, intermediate filament proteins. Unlike Tektin A1, Tektin B1 lacks any part of the C-terminal IFP consensus sequence.
Ekowati Chasanah - One of the best experts on this subject based on the ideXlab platform.
-
karakterisasi biokimia lektin makroalga sargassum polycystum dan turbinaria ornata
Jurnal Pascapanen dan Bioteknologi Kelautan dan Perikanan, 2018Co-Authors: Nurrahmi Dewi Fajarningsih, Naomi Intaqta, Danar Praseptiangga, Choiroel Anam, Ekowati ChasanahAbstract:Abstrak Kemampuan lektin untuk mengikat karbohidrat secara spesifik dan reversible dapat dikembangkan dalam berbagai aplikasi, misalnya sebagai reagen histokimia. Penelitian ini bertujuan untuk mempelajari spesifisitas pengikatan lektin makroalga Sargassum polycystum dan Turbinaria ornata pada berbagai jenis karbohidrat, stabilitas aktivitas hemaglutinasi lektin pada berbagai rentang suhu dan pH, serta pengaruh kation divalen pada aktivitasnya. Uji penghambatan hemaglutinasi secara kualitatif dan kuantitatif dilakukan untuk mempelajari spesifisitas pengikatan lektin terhadap 20 jenis gula dan glikoprotein. Untuk melihat stabilitas aktivitasnya, lektin S. polycystum dan T. ornata diberi perlakuan pemanasan pada rentang suhu 30-100 oC, perlakuan pH 3-10 dan perlakuan kation divalen MgCl2 dan CaCl2 kemudian diuji aktivtitas hemagglutinasinya. Ekstrak kaya lektin S. polycystum dan T. ornata mampu mengenali dan mengikat 8 glikoprotein secara kualititatif, yaitu fetuin (Fe), asialo Fe (aFe), thyroglobulin from bovine (BTG), asialo BTG, thyroglobulin from porcine (PTG), asialo PTG (aPTG), asialo mucin from bovine submaxillary glands (aBSM), dan asialo transferrin (aTf), namun tidak mempunyai afinitas terhadap gula sederhana. Lektin S. polycystum memiliki spesifisitas pengikatan terbaik terhadap aFe dan transferrin (Minimum Inhibitory Concentration/MIC 250 µg/ml), sementara Lektin T. ornata memiliki spesifisitas pengikatan terbaik terhadap aPTG (MIC 31.25 µg/ml), PTG (MIC 125 µg/ml), dan BTG (MIC 250 µg/ml). Aktivitas hemaglutinasi lektin S. polycystum stabil pada suhu 30-80 oC dan suasana netral hingga basa (pH 7-10), namun kurang stabil pada suasana asam (pH 3-6). Aktivitas lektin T. ornata relatif tidak stabil pada suhu 40-100 oC, sedikit menurun pada pH sangat asam, namun stabil pada rentang pH 5-10. Keberadaan kation divalent Ca2+ dan Mg2+ sedikit menurunkan aktivitas lektin S. polycystum dan T. ornata . Biochemical Characterisation of Lectin Derived from Sargassum polycystum and Turbinaria ornata Macroalgae Abstract The ability of lectins to specifically and reversibly bind carbohydrates is an important characteristics for its various applications. This research aims to study the binding specificity of Sargassum polycystum and Turbinaria ornata lectin rich extracts to various types of carbohydrates, the stability of both lectins hemagglutination activities at various temperatures and pH, and the effects of divalent cations on the lectin activities. The lectin binding specificity was studied through qualitative and quantitative hemagglutination inhibition studies. To study their activity stability, both lectins were treated at 30 to 100 oC, treated with various pH buffers (pH 3-10), treated with MgCl2 and CaCl2 followed with hemagglutination assay. Both lectins bound 8 glycoproteins tested, i.e. fetuin (Fe), asialo Fe (aFe), thyroglobulin from bovine (BTG), asialo BTG, thyroglobulin from porcine (PTG), asialo PTG (aPTG), asialo mucin from bovine submaxillary glands (aBSM), and asialo transferrin (aTf) but did not have any affinity to the simple sugars. The S. polycystum lectin bound to aFe and transferrin (MIC 250 µg/ml). Meanwhile, the T. Ornata lectin specifically bound to aPTG (MIC 31.25 µg/ml), PTG (MIC 125 µg/ml), and BTG (MIC 250 µg/ml). The hemagglutination activity of S. polycystum lectin was stable at 30-80 oC and in neutral to alkaline conditions (pH 7-10), but less stable in acidic conditions (pH 3-6). The T. ornata lectin activity was relatively unstable at 40-100 oC, slightly decreased at a very acidic pH, butwas stable in a pH range of 5-10. The presence of Ca2+ and Mg2+ divalent cations slightly decreased the lectins activities.
-
Karakterisasi Biokimia Lektin Makroalga Sargassum polycystum dan Turbinaria ornata
Pusat Penelitian dan Pengembangan Daya Saing Produk dan Bioteknologi Kelautan dan Perikanan, 2018Co-Authors: Nurrahmi Dewi Fajarningsih, Naomi Intaqta, Danar Praseptiangga, Choiroel Anam, Ekowati ChasanahAbstract:Kemampuan lektin untuk mengikat karbohidrat secara spesifik dan reversible dapat dikembangkan dalam berbagai aplikasi, misalnya sebagai reagen histokimia. Penelitian ini bertujuan untuk mempelajari spesifisitas pengikatan lektin makroalga Sargassum polycystum dan Turbinaria ornata pada berbagai jenis karbohidrat, stabilitas aktivitas hemaglutinasi lektin pada berbagai rentang suhu dan pH, serta pengaruh kation divalen pada aktivitasnya. Uji penghambatan hemaglutinasi secara kualitatif dan kuantitatif dilakukan untuk mempelajari spesifisitas pengikatan lektin terhadap 20 jenis gula dan glikoprotein. Untuk melihat stabilitas aktivitasnya, lektin S. polycystum dan T. ornata diberi perlakuan pemanasan pada rentang suhu 30-100 oC, perlakuan pH 3-10 dan perlakuan kation divalen MgCl2 dan CaCl2 kemudian diuji aktivtitas hemagglutinasinya. Ekstrak kaya lektin S. polycystum dan T. ornata mampu mengenali dan mengikat 8 glikoprotein secara kualititatif, yaitu fetuin (Fe), asialo Fe (aFe), thyroglobulin from bovine (BTG), asialo BTG, thyroglobulin from porcine (PTG), asialo PTG (aPTG), asialo mucin from bovine submaxillary glands (aBSM), dan asialo transferrin (aTf), namun tidak mempunyai afinitas terhadap gula sederhana. Lektin S. polycystum memiliki spesifisitas pengikatan terbaik terhadap aFe dan transferrin (Minimum Inhibitory Concentration/MIC 250 µg/ml), sementara Lektin T. ornata memiliki spesifisitas pengikatan terbaik terhadap aPTG (MIC 31.25 µg/ml), PTG (MIC 125 µg/ml), dan BTG (MIC 250 µg/ml). Aktivitas hemaglutinasi lektin S. polycystum stabil pada suhu 30-80 oC dan suasana netral hingga basa (pH 7-10), namun kurang stabil pada suasana asam (pH 3-6). Aktivitas lektin T. ornata relatif tidak stabil pada suhu 40-100 oC, sedikit menurun pada pH sangat asam, namun stabil pada rentang pH 5-10. Keberadaan kation divalent Ca2+ dan Mg2+ sedikit menurunkan aktivitas lektin S. polycystum dan T. ornata
Hiroshi Iida - One of the best experts on this subject based on the ideXlab platform.
-
characterization and subcellular localization of Tektin 3 in rat spermatozoa
Molecular Reproduction and Development, 2011Co-Authors: Hiroe Takiguchi, Emi Murayama, Takane Kaneko, Hitoshi Kurio, Kiyotaka Toshimori, Hiroshi IidaAbstract:Mammalian sperm flagella have filament-forming Tektin proteins (Tektin 1-5) reported to be involved in the stability and structural complexity of flagella. Male mice null for Tektin3 produce spermatozoa with reduced forward progression and increased flagellar structural bending defects. The subcellular localization of Tektin3 (TEKT3) in spermatozoa, however, has not been clarified at the ultrastructural level. To elucidate the molecular localization of TEKT3 in flagella of rat spermatozoa, we performed extraction studies followed by immunoblot analysis, immunofluorescence microscopy, and immunogold electron microscopy. Extraction of sperm flagella from the cauda epididymis resulted in complete removal of axonemal tubulins, while TEKT3 was resistant to extraction with the same S-EDTA (1% SDS, 75 mM NaCl, 24 mM EDTA, pH 7.6) solution, suggesting that TEKT3 might be present in the peri-axonemal component and not directly associated with axonemal tubulins. Resistance to S-EDTA extraction might be due to disulfide bond formation during epididymal maturation since concentrations of DTT greater than 5 mM drastically promoted release of TEKT3 from flagella. Immunofluorescence microscopy and pre-embedding immunoelectron microscopy revealed that TEKT3 was predominantly associated with the surface of mitochondria and outer dense fibers in the middle piece. In addition, TEKT3 was found to be present at the equatorial segment region of the acrosome membrane in sperm heads. TEKT3 might not only work as a flagellar constituent required for flagellar stability and sperm motility but also may be involved in acrosome-related events, such as the acrosome reaction or sperm-egg fusion.
-
Tektin5 a new Tektin family member is a component of the middle piece of flagella in rat spermatozoa
Molecular Reproduction and Development, 2008Co-Authors: Emi Murayama, Etsuko Yamamoto, Takane Kaneko, Yosaburo Shibata, Tetsuichiro Inai, Hiroshi IidaAbstract:Tektins are composed of a family of filament-forming proteins localized in cilia and flagella. Four types of mammalian Tektins have been reported, and at least two types of Tektins, Tektin2 and Tektin4, have been verified to be present in sperm flagella. A new member of the Tektin gene family, which was designated as rat Tektin5, was obtained by PCR technique. Rat Tektin5 cDNA consists of 1,674 bp encoding a 62.8 kDa protein of 558 amino acids. Tektin5 protein contains a Tektin domain as well as a nonapeptide signature sequence that is a prominent feature of Tektin proteins. RT-PCR analysis indicated that Tektin5 was predominantly expressed in testis and that its expression was up-regulated during testis development. Immunoblot analyses revealed that Tektin5 is present in sperm flagella but not in heads and that it is completely released from rat spermatozoa by 6 M urea treatment, but not extracted by 1% Triton X-100 and 0.6 M potassium thiocyanate. Confocal laser scanning microscopy revealed that Tektin5 was located in the middle piece of flagella in rat spermatozoa with no immunolabeling in the heads and the principal piece. Immunogold electron microscopy adopting pre-embedding method discovered that Tektin5 is predominantly associated with the inner side of the mitochondrial sheath. Tektin5 might work as a middle piece component requisite for flagellar stability and sperm motility. Mol. Reprod. Dev. 75: 650–658, 2008. © 2007 Wiley-Liss, Inc.
-
Tektin 4 is located on outer dense fibers not associated with axonemal tubulins of flagella in rodent spermatozoa
Molecular Reproduction and Development, 2006Co-Authors: Hiroshi Iida, Yosaburo Shibata, Takuya Matsuyama, Yoshiko Honda, Tetsuichiro InaiAbstract:Tektins, which are thought to be the constitutive proteins of microtubules in cilia, flagella, basal bodies, and centrioles, have been reported to be involved in the stability and structural complexity of axonemal microtubules. Four types of mammalian Tektins have been reported, and at least two types of Tektins, Tektin 2 and Tektin 4, have been verified to be present in sperm flagella. To elucidate the molecular localization of Tektin 4 in flagella of rodent spermatozoa, we performed immunocytochemistry, fractionation study followed by immunoblot analysis, and immunogold electron microscopy. Confocal laser scanning microscopy and immunogold electron microscopy indicated that Tektin 4 was associated with outer dense fibers (ODFs) in both the middle and principal piece of flagella in rat and mouse spermatozoa. Tektin 4 in rat spermatozoa is completely released by 6 M urea treatment, but not extracted by 1% Triton X-100 and 0.6 M potassium thiocyanate. Pre-embedding immunoelectron microscopy demonstrated that Tektin 4 located on the abaxial (convex) surface of ODFs in flagella, not associate with axonemal microtubules. Our data strongly suggested that Tektin 4 is not associated with axonemal tubulins but an ODFs-affiliated molecule in rodent spermatozoa.
-
molecular cloning of a new member of Tektin family Tektin4 located to the flagella of rat spermatozoa
Molecular Reproduction and Development, 2005Co-Authors: Takuya Matsuyama, Yoshiko Honda, Masamichi Doiguchi, Hiroshi IidaAbstract:Tektins are composed of a family of filament-forming proteins associated with ciliary and flagellar microtubules. A new member of the Tektin gene family, which was designated as rat Tektin4, was obtained by PCR technique combined with yeast two-hybrid screening. Rat Tektin4 cDNA consists of 1,341 bp encoding a 52 kDa protein of 447 amino acids. Tektin4 protein contains a Tektin domain including a nonapeptide signature sequence (RPNVELCRD), which is a prominent feature of Tektins. Its amino acid sequence showed 29% ∼ 58% identities to that of other Tektin family proteins registered in the public databases. Tektin4 gene, which was mapped to rat chromosome 10q12, is composed of six exons and spanning 5 kb. Reverse-transcriptional-PCR (RT-PCR) analysis indicated that Tektin4 was predominantly expressed in testis and its expression was upregulated during testis development. In situ hybridization analysis showed that Tektin4 mRNA was localized in round spermatids in the seminiferous tubules of the rat testis. Tektin4 protein was predominantly localized in the flagella of spermatozoa, suggesting that it might works as a flagellar component requisite for flagellar stability or sperm motility. © 2005 Wiley-Liss, Inc.
