bluuebunny/crossref_metadata_2025_split huggingface dataset:
The biochemical role of SRY in sex determination
Authors: R. Harley V. , N. Goodfellow P. 
Published: February 2005

AbstractThe human sex‐determining gene on the Y chromosome, termed SRY, has recently been isolated by positional cloning; compelling evidence now exists equating SRY with the testis‐determing factor, TDF. The SRY gene product is an HMG box protein whose DNA‐binding activity is vital for testis formation as sex‐reversed patients with SRY mutations lack this activity in vitro. The in vivo DNA target for SRY, however, remains elusive. Here, we show, by gel retardation analysis, that SRY recognises specific DNA sequences and that such sequences exist upstream of the AMH promoter, a potential downstream target for SRY. We also describe the DNA bending and cruciform DNA‐binding functions of SRY and propose a model for the potential action of SRY in the “HMG‐1‐rich” mammalian nucleus. © 1994 Wiley‐Liss, Inc.
Regulation of gene expression by transcription factors Ets‐1 and Ets‐2
Authors: J. Tymms Martin , Kola Ismail 
Published: February 2005

AbstractThe ETS family of transcription factors have a DNA‐binding domain in common that binds a core GGA(A/T) DNA sequence. A large number of proteins have now been identified that contain an ETS DNA‐binding domain (see review by Wasylyk et al., 1993). Ets‐1 was first described as the cellular homolog of v‐ets, which is translated as a 135‐kDa gag–myb—ets fusion protein from the replication‐deficient retrovirus E26 in chickens. Ets‐2 was subsequently described as a closely related protein that contains the highly conserved ETS DNA‐binding domain. This paper considers the manner by which the two closely related genes, Ets‐1 and Ets‐2, apparently play distinct roles in embryo development and in the immune system of adult mice. Although both Ets‐1 and Ets‐2 transform fibroblasts (Seth et al., 1989), the temporal and tissue‐specific expression patterns suggest that these two proteins play distinct biological roles and consequently transactivate different downstream cellular target genes. © 1994 Wiley‐Liss, Inc.
Discriminating translation of insulin‐like growth factor‐II (IGF‐II) during mouse embryogenesis
Authors: Newell Susan , Ward Andrew , Graham Chris 
Published: February 2005

AbstractThe problem is to discover which of the promoters of the insulin‐like growth factor‐II gene stimulate the transcription of mRNA which is translated into protein. Three alternative leader exons are attached to the coding sequences in RNA transcribed from this gene in other systems, and it is mainly the paternal allele which is expressed in mouse development. Transcripts bearing each of the three leader exons were found in the RNA from the chorio‐allantoic placenta, visceral yolk sac, and embryo, starting at 9.5 days. A varying proportion of one abundant transcript was disengaged from the polysomes at different days of development. This transcript was prefixed by the longest of the three alternative untranslated 5′ leader exons (exon 2), and it was consistently associated with polysomes in the choroid plexus and leptomeninges of the brain. Many exon 2 transcripts were abbreviated by endonucleolytic cleavage and lacked a poly(A) tail. In contrast, the transcripts with the shortest leader (exon 3) were mainly displayed on polysomes at all the stages of development which were examined. During mouse development, the production of IGF‐II protein must be partly controlled by the mechanisms which regulate translation. © 1994 Wiley‐Liss, Inc.
Characterization of two antigenically related integral membrane proteins of the guinea pig sperm periacrosomal plasma membrane
Authors: Anne Westbrook‐Case V. , P. Winfrey Virginia , E. Olson Gary 
Published: February 2005

AbstractThe periacrosomal plasma membrane of mammalian spermatozoa functions both in recognition and in binding of the egg's zona pellucida and in the acrosome reaction. This study characterizes two antigenically related proteins with molecular weights of 35 kD (PM35) and 52 kD (PM52) of the guinea pig sperm periacrosomal plasma membrane. Polyclonal antisera were prepared against electrophoretically purified PM35 or PM52. Each antiserum recognized both the 35‐kD and 52‐kD polypeptides on Western blots, indicating that they are structurally related. This conclusion was supported by peptide mapping experiments demonstrating comparably sized fragments of both PM35 and PM52. Both PM35 and PM52 behave as integral membrane proteins during phase‐separation analysis with Triton X‐114. Electron microscopic immunocytochemistry and differential fractionation of sperm membranes established that both PM35 and PM52 are exclusively localized to the periacrosomal plasma membrane. Three different antisera were used for ultrastructural studies, and each specifically bound the cytoplasmic but not the extracellular membrane surface. The electrophoretic mobilities of the PM35 and PM52 polypeptides were unchanged during sperm maturation and during the ionophore‐induced acrosome reaction. The localization of PM35 and PM52 suggests a potential role for these integral plasma membrane proteins in signal transduction or membrane fusion events of the acrosome reaction. © 1994 Wiley‐Liss, Inc.
Molecular identities of human sperm proteins that bind human zona pellucida: Nature of sperm–zona interaction, tyrosine kinase activity, and involvement of FA‐1
Authors: K. Naz Rajesh , Ahmad Khaliq 
Published: February 2005

AbstractThe present study was conducted to investigate the molecular identities, nature of interaction, and tyrosine phosphorylation activity of the spermzona pellucida binding proteins in humans. Sperm proteins belcnging to four major molecular regions, namely 95, 63, 51, and 14–18 kDa, reacted with zona pellucida proteins in the Western blot and immunoprecipitation procedures. In these procedures, zona pellucida protein that reacted strongest with the sperm proteins belonged to the molecular region of 55 kDa (ZP3), besides weakly reacting proteins in the 110‐kDa (ZP1/ZP2) and 14–18‐kDa molecular regions. The major forces involved in the sperm‐zona protein interactions were of hydrophobic and ionic in nature. Three (95, 51, and 14–18 kDa) of the four molecular regions of sperm proteins that bound to the zona pellucida proteins also seem to involve o‐phospho‐L‐tyrosine residues in their interaction, and these proteins demonstrated the presence of phosphotyrosine residues, and the 51‐kDa protein also showed autophosphorylating activity in the in vitro kinase assay. The sperm binding zona protein of 55 kDa also demonstrated autophosphorylating activity. Using specific monoclonal antibody to the well characterized sperm‐specific glycoprotein, designated FA‐1, and the competitive inhibition in the immunoprecipitation procedure, it was found that the 51 kDa protein is indeed FA‐1 antigen. Besides elucidating the molecular nature of the spermzona interaction, these antigens will find application in the development of a multivalent contraceptive vaccine, and may also help in specific diagnosis and treatment of infertility mediated through defective gamete (sperm or oocyte) function. © 1994 Wiley‐Liss, Inc.
Tissue‐Specific variation in the length of the 5′ untranslated region of the βa‐inhibin mRNA in sheep
Authors: Fleming J. S. , Galloway S. M. , Crawford R. J. , Tisdall D. J. , Greenwood P. J. 
Published: February 2005

AbstractThe 5′ untranslated region (UTR) of βA inhibin mRNA was compared in a variety of sheep tissues, using primer extension. Considerable variation in the length and number of 5′ extended products were noted between tissues. Specific bands were noted in ovarian follicular RNA, which were also present in samples from corpora lutea, stroma, and placental cotyledon RNA. Other extended products were observed in RNA from corpora lutea, stroma, cotyledon, pituitary, bone marrow, frontal cortex, medial basal hypothalamus, adrenal, liver, and kidney, which were not present or weakly represented in follicular RNA, Additional tissue‐specific bands were noted in testis and bone marrow RNA. No specific differences in the lengths of the 5′ UTR of the βA inhibin mRNA were observed in sheep homozygous for the Booroola fecundity gene FecB, in any tissue studied. The coding region of ovine βA inhibin cDNA was sequenced and a genetic polymorphism confirmed within or close to the ovine βA inhibin gene.We conclude that the βA inhibin gene is expressed widely in the sheep. Furthermore there is variation in the length of the 5′ UTR of βA inhibin mRNA between male and female gonads and other tissues, implying that expression of this gene is differentially controlled. However, the FecB mutation does not affect mRNA splicing events or the initiation site used in ovarian transcription. The mechanism by which the FecB mutation influences the amounts of βA inhibin mRNA, follicle‐stimulating hormone (FSH) secretion and ovulation rate has still to be elucidated. © 1995 Wiley‐Liss, Inc.
Endogenous substrate for energy metabolism and ultrastructural correlates in spermatozoa of the sea urchin Diadema setosum
Authors: Mita Masatoshi , Yasumasu Ikuo , Nakamura Masaru 
Published: February 2005

AbstractEnergy metabolism in spermatozoa of the sea urchin Diadema setosum of the order Diadematoida was examined. The spermatozoa contained not only several kinds of phospholipids and cholesterol, but also triglyceride (TG). Glycogen and glucose were present at extremely low levels. Following dilution of dry sperm and incubation in seawater, the TG content decreased rapidly. Other lipids, however, remained at constant levels, except for a slight increase in the level of free fatty acid. High lipase activity was demonstrated in the spermatozoa. 14C‐labeled fatty acid was oxidized to 14CO2. Ultrastructural study also showed that lipid globules were present at the bottom of the midpiece. After incubation in seawater, morphological changes in the lipid globules were observed and some vacuoles appeared. Thus, the results obtained strongly suggest that D. setosum spermatozoa obtain energy through oxidation of fatty acid from TG stored in the lipid globules at the midpieces. © 1995 Wiley‐Liss, Inc.
Vitelline coat of Unio elongatulus: II. Biochemical properties of the 220‐ and 180‐kD components
Authors: Focarelli R. , Santucci A. , Lampariello R. , Rosati Floriana 
Published: February 2005

AbstractIn a previous study we found that two glycoproteins with apparent molecular weights of 220 kD and 180 kD account for 80–90% of the material dissolved from the vitelline coat of the egg of the bivalve mollusk, Unio elongatulus (Focarelli and Rosati, 1993: Mol Reprod Dev 35:44–51). In this study we isolated and purified these glycoproteins by electroelution. The two proteins differ in many respects: the 180‐kD molecule is acidic in nature and highly heterogeneous, whereas the 220‐kD protein is neutral and less heterogeneous. Both seem to have O‐ and N‐linked oligosaccharide chains. The 180‐kD protein contains 13–16% carbohydrate, whereas the 220‐kD molecular contains only 7–8%. Amino acid analysis and peptide mapping also show that each protein represents a unique polypeptide chain. © 1995 Wiley‐Liss, Inc.
Molecular mechanisms of the antihormonal and antiimplantation effects of norethisterone and its a‐ring reduced metabolites
Authors: Castro Ivone , Cerbón Marco Antonio , Pasapera Ana Maria , GutiéRrez‐sagal Ruben , Garcia Gustavo A. , Orozco Carlos , Camacho‐Arroyo Ignacio , Anzaldua Rene , PéRez‐Palacios Gregorio 
Published: February 2005

AbstractNorethisterone (NET) has been used as a contragestational postcoital agent. It is biotrans‐formed to 5α dihydro‐NET (5α‐NET) and 3β,5α tetrahydro‐NET (3β,5α‐NET) in target tissues. The participation of these metabolites in NET effects is unknown. We have examined the antiimplantation and antiprogestational effects of NET and its metabolites, in adult mated female rabbits, by assessing the number of implantation sites and the expression products of the uteroglobin (UTG) gene in the uterus, and by comparing them with those of RU‐486 and estradiol. Steroids were daily administered s.c. at several doses for 7 consecutive days, starting 24 hr after coitus. To assure that fertilization occurred in all animals, the presence of early pregnancy factor was determined. The results demonstrated that high doses (5 mg/kg) of NET reduced both implantation and the expression of the UTG gene. On the other hand, lower doses (1.5 mg/kg) of 5α‐NET produced an antiimplantation effect and suppressed UTG synthesis and its mRNA. These effects were similar to those of RU‐486. At lower doses (1 mg/kg), both estradiol and the estrogenic metabolite 3β,5α‐NET were also effective in inhibiting implantation and UTG gene expression. The overall results suggest that NET metabolites exert antiimplantation and antiprogestational effects through their interaction with progesterone and estrogen receptors, and provide an explanation for the molecular mechanisms involved in the postcoital contraceptive action of NET. © 1995 Wiley‐Liss, Inc.
In vitro viability and ultrastructural changes in bovine oocytes treated with a vitrification solution
Authors: Fuku Eiji , Liu Jianmin , Downey Bruce R. 
Published: February 2005

AbstractAbattoir‐derived oocytes were exposed to a concentrated cryoprotectant solution (DAP213: 2 M DMSO, 1 M acetamide, 3 M propanediol, and 10% FCS in TCM199) for 1.5 or 5 min at the germinal vesicle (GV) stage or after maturation in vitro (IVM). Their viability was assessed by in vitro fertilization (IVF) and culture (IVC) to blastocysts. To investigate the effect of DAP213 on the ultrastructure, GV and IVM oocytes were processed for transmission electron microscopy (TEM) before (control) or after exposure to the cryoprotectant. DAP213 induced profound ultrastructural modifications to the microvilli and mitochondria, resulted in large vesicle formation, and, most significantly, caused the premature release of the cortical granules (CG). In IVM oocytes exposed to the cryoproteclant for 5 min, exocytosis of CG into the perivitelline space was common and the IVF rate was reduced (P <.05). After exposure for 5 min, GV oocytes displayed clusters of CG comparable to controls, but after IVM‐IVF, polyspermy rate was increased (P <.05). Furthermore, treated GV oocytes showed a reduced rate of cleavage and blastocyst formation and an increased percentage of oocytes exhibiting alterations in organelles, whereas the viability and ultrastructure of IVM oocytes treated for 1.5 min was not different from controls. These observations demonstrate that (1) cortical granule kinetics is one of the key elements controlling fertilizability of bovine oocytes treated with cryoprotectant, and (2) GV oocytes are more sensitive to the cryoprotectant than those that have already been matured in vitro.
Characterization of the heat shock protein P70 in rat spermatogenic cells
Authors: Raab Linda S. , Polakoski Kenneth L. , Hancock Larry W. , Hamilton David W. 
Published: February 2005

AbstractA number of hsp70‐like proteins are associated with developing male germ cells. One of these molecules, P70, is not sensitive to heat stress and is germ cell‐specific, and its expression is developmentally regulated. We have characterized the association of the rat P70(rP70) with differentiating germ cells in the testis and with posttesticular sperm. An antibody originally raised against human sperm proacrosin (designated C3; Siegel et al., 1987: J Reprod Immunol 11:307–319) was found to immunostain rP70 by immunoblot analysis and was used in subsequent studies of the rP70 molecule. The C3 antibody reacted with P70 isoforms in rat, human, mouse, guinea pig, boar, and rooster testicular homogenates. In the developing rat testis, abundant rP70 protein levels were first detected on postnatal day 22, with upregulation to adult levels occurring after postnatal day 28. Purified populations of adult rat pachytene spermatocytes, round spermatids, and elongating spermatids, isolated by unit gravity velocity sedimentation, all expressed rP70. Posttesticular sperm exhibited a loss of the rP70 molecule; caput epididymal sperm were weakly immunoreactive for rP70, but no immunoreactivity was observed in either cauda epididymal sperm or epididymal fluid. In contrast to human ejaculated sperm, rat ejaculated sperm did not express rP70. The loss of P70 from rat posttesticular sperm may reflect species‐specific differences in P70 functions, which are thought to include a role in the structural modifications that occur during germ cell differentiation. © 1995 Wiley‐Liss, Inc.
Vitelline coat of Unio elongatulus: III. Glycan chain analysis of the 220‐ and 180‐kD components by means of lectins
Authors: Focarelli R. , Leotta F. , Lampariello R. , Rosati Floriana 
Published: February 2005

AbstractLectins of different binding specificity were used to analyze the oligosaccharide chains of the 220‐ and 180‐kD proteins of the Unio elongatulus egg vitelline coat (vc). The lectins ConA and RCA1 reacted with both glycoproteins, and four other lectins reacted with one or other vc components. The lectin from Galanthus nivalis, which recognizes terminal mannose residues of N‐linked high mannose type oligosaccharide chains, bound specifically to the 180‐kD protein. Binding sites for this lectin were found throughout the vc of the differentiating oocyte and the mature egg. Lectins specific for the O‐linked oligosaccharide chains, such as AIA and PNA, reacted only with the 220‐kD protein species. Binding sites for these lectins were found only in the crater region. The presence of fucosyl residues on the glycan chains was investigated with lectins from Lotus tetragonolobus and Aleuria aurantia. The latter was positive on both glycoproteins, whereas LTA was only positive to the 220‐kD species. The binding sites of both these lectins were in the same areas as those of PNA and AIA. These results suggest that while the 180‐kD protein is part of the entire vc structure, the 220‐kD protein is prevalently accumulated in the crater region. Since this is where sperm recognition and interaction take place, it has been suggested the 220‐kD protein acts as a ligand molecule in the sperm‐egg interaction. © 1995 Wiley‐Liss, Inc.
Ca2+‐Regulating mechanisms that modulate bull sperm capacitation and acrosomal exocytosis as determined by chlortetracycline analysis
Authors: Fraser Lynn R. , Abeydeera L. R. , Niwa K. 
Published: February 2005

AbstractWe have used chlortetracycline (CTC) analysis to investigate mechanisms that may play important roles during bull sperm capacitation in a culture medium (containing glucose, heparin, and caffeine) known to promote capacitation and fertilization in vitro. In initial experiments employing the Ca2+ ionophore A23187, we identified three discrete CTC patterns so similar to those described for mouse and human sperm that we have employed the same nomenclature: “F,” characteristic of uncapacitated, acrosome‐intact cells; “B,” characteristic of capacitated, acrosome‐intact, cells; “AR,” characteristic of capacitated, acrosome‐reacted cells. Over a 60‐min period, A23187 stimulated significant increases in B and AR pattern cells, with concomitant decreases in F pattern cells, suggesting a very rapid transition from the uncapacitated to the capacitated state and then on to exocytosis. Without ionophore, significant changes in the proportions of F and B pattern cells were also observed, but the maximum responses required 4 hr; the proportion of AR cells was consistently ∼ 15% throughout, indicating a low incidence of spontaneous acrosome loss. Analysis of cells in media with altered composition indicated that the inclusion of either heparin or caffeine significantly promoted capacitation to about the same extent, but together, heparin plus caffeine had an even more stimulatory effect. Despite this, none of these treatments triggered acrosome loss above the levels seen in media lacking these constituents. In the presence of caffeine, with or without heparin, the inclusion of glucose had little effect on responses, but in the presence of heparin there were fewer B cells. In the presence of either quercetin, a Ca‐ATPase inhibitor used at 50–200 μM, or W‐7, a calmodulin antagonist used at 5–125 μM, capacitation per se was accelerated, as evidenced by significant decreases in F and significant increases in B pattern cells; only the highest concentration of each caused significant increases in AR cells. In addition, 25 and 125 μM W‐7 markedly stimulated motility, both quantitatively and qualitatively. Finally the Na+ ionophore monensin at 500 μM significantly accelerated both capacitation and acrosomal exocytosis. The addition of the dihydropyridine calcium channel blocker nifedipine at 10 nM, just prior to monensin, did not inhibit capacitation (F to B transition) but blocked acrosomal exocytosis (B to AR transition). We suggest that Ca2+ is required for functional changes in bull sperm, with a Ca2+‐ATPase modulating intracellular Ca2+ during capacitation and calcium channels controlling the Ca2+ influx required for acrosomal exocytosis. © 1995 Wiley‐Liss, Inc.
Cloning and partial characterization of the cDNA encoding the fox sperm protein FSA‐Acr.1 with similarities to the SP‐10 antigen
Authors: Beaton Sandra , Have José ten , Cleary Andrew , Bradley Mark P. 
Published: February 2005

AbstractWe have isolated and characterized a cDNA, cFSA‐Acr.1, encoding a testis‐specific fox sperm antigen. The antigen is located on the inner acrosomal compartment, and is expressed during spermatogenesis on the developing acrosome of round and elongating spermatids. Database searches with the deduced amino acid sequence of cFSA‐Acr.1 revealed that the clone has high homology to both human and baboon sperm protein SP‐10, and the mouse sperm protein, MSA‐63. The region of highest homology is within the carboxyl terminus. In the middle of the open reading frame, the fox sequence shows unique sequences absent from both the human, baboon SP‐10, and mouse MSA‐63 sequences. In addition to cFSA‐Acr.1, two other clones were also isolated from the same fox testis cDNA library, and sequence analysis shows that they may represent alternatively spliced mRNAs coding for other FSA‐Acr proteins. © 1995 Wiley‐Liss, Inc.
Inactivation of histone H1 kinase by Ca2+ in rabbit oocytes
Authors: Collas Philippe , Chang Thomas , Long Charles , Robl James M. 
Published: February 2005

AbstractThe present study investigated the role of intracellular Ca2+ (Ca2+i) elevation on the inactivation of maturation promoting factor (MPF) in rabbit oocytes. The effects of the number of Ca2+ stimulations and of the amplitude of Ca2+i elevation on the profile of histone H1 kinase activity were determined. A Ca2+ stimulation consisted of transferring mature oocytes from culture medium to 0.3 M mannitol containing 0.1–1.0 mM CaCl2, and pulsing them at 1.25 kV/cm for 10 μsec, or microinjecting 2–8 mM CaCl2 into the oocyte cytoplasm. The number of electrically‐induced Ca2+ stimulations was varied, and amplitude of the Ca2+i rise was controlled by altering Ca2+ concentration in the pulsing medium or the injection pipette. Ca2+i concentration was determined with fura‐2 dextran; oocytes were snap‐frozen at indicated time points and assayed for H1 kinase activity. The activity was quantified by densitometry and expressed as a fraction of activity in nonstimulated oocytes. Electrically‐mediated Ca2+i rises inactivated H1 kinase in a manner dependent on the number of Ca2+ stimulations. A single Ca2+ stimulation inactivated H1 kinase to 30–40% of its initial activity. However, H1 kinase inactivation was only transient, regardless of the amplitude of the electrically‐ or injection‐mediated Ca2+i elevation. Increasing the number of Ca2+ stimulations helped to maintain H1 kinase activity at basal (pronuclear) levels. The results show the necessity of a threshold of Ca2+i concentration to trigger MPF inactivation, and suggest a role for the extended period of time over which Ca2+i oscillates at fertilization. © 1995 Wiley‐Liss, Inc.