bluuebunny/crossref_metadata_2025_split huggingface dataset:
Developmentally regulated protease expression during sea urchin embryogenesis
Authors: Vafa Omid , Nishioka David 
Published: February 2005

AbstractA temporal study of protease expression employing the technique of SDS‐PAGE gelatin substrate zymography revealed a definitive appearance of proteases during early development in the sea urchins, Lytechinus pictus and Strongylocentrotus purpuratus. The levels of these proteases increase substantially during gastrulation in each species. The two major proteases with relative molecular masses of 57 and 50 kDa were found to be inhibited by the zinc chelator, 1,10‐phenanthroline, the more nonspecific metal chelator, EDTA, and the reducing agent, dithiothreitol. The serine protease inhibitor, benzamidine, exerted no effects on the activities of these proteases, and both enzymes exhibited activity in the neutral to slightly basic pH range. Treatment of embryos with actinomycin D, an inhibitor of transcription, beginning up to 9 hr after fertilization, inhibited the subsequent appearances of the two proteases 48 hr after fertilization, as well as any morphological changes associated with gastrulation. Treatments beginning 15 and 21 hr after fertilization resulted in increased levels of proteases that correlate with arrests at successively more advanced stages of gastrulation. SDS‐PAGE zymographic analyses of five different embryo fractions indicated that the 57‐ and 50‐kDa proteases are localized in the blastocoel, and blastocoelic protease activity was further confirmed microscopically by in situ zymography. Hence, the 57‐ and 50‐kDa proteases are characterized as metalloproteases. Their expression is dependent on transcription of the embryonic genome, and their spatiotemporal appearance suggests an involvement in blastocoelic matrix remodeling during gastrulation. © 1995 Wiley‐Liss, Inc.
Persistence of protamine precursors in mature sperm nuclei of the mouse
Authors: Debarle Michel , Martinage Arlette , Sautiere Pierre , Chevaillier Philippe 
Published: February 2005

AbstractDuring mouse spermiogenesis, two protamines, mP1 and mP2, are synthesized in replacement of histones. One of them (protamine mP2, 63 residues) appears at first in elongating spermatid nuclei as a pro‐protamine of 106 residues (pmP2) with an amino‐terminal extension that is progressively excised. The two protamines were previously described as the only proteins associated with DNA in sperm chromatin.This paper shows that the nuclear proteins of mouse spermatozoa are indeed heterogeneous: at least six minor polypeptides in addition to protamines can be identified. The primary structure of four of them has been established. They are intermediate in the maturation of the precursor of protamine mP2 and correspond to polypeptides pmP2/11, pmP2/16, pmP2/20, and pmP2/32, characterized previously in mouse testis. Therefore, these intermediates of proteolysis generated from pmP2 inside spermatid nuclei persist in mature sperm, whereas the largest precursors, pmP2 and pmP2/5, disappear. These findings clearly indicate that limited proteolysis events still occur outside of the testis. © 1995 Wiley‐Liss, Inc.
Role of sulfated glycoprotein‐1 (SGP‐1) in the disposal of residual bodies by sertoli cells of the rat
Authors: Igdoura Suleiman A. , Morales Carlos R. 
Published: February 2005

AbstractSulfated glycoprotein‐1 (SGP‐1) is a polypeptide secreted by Sertoli cells in the rat. Sequence analysis revealed a 76% sequence similarity with human prosaposin produced by various cell types. Human prosaposin is a 70 kDa protein which is cleaved in the lysosomes into four 10–15 kDa polypeptides termed saposins A, B, C, and D. The function of lysosomal saposins is to either solubilize certain membrane glycolipids or to form complexes with lysosomal enzymes and/or their glycolipid substrate to facilitate their hydrolysis. The present investigation dealt with the delivery of SGP‐1 into the phagosomes of Sertoli cells; these phagosomes contain the residual bodies which detach from the late spermatids at the time of spermiation. Immunogold labeling with anti‐SGP‐1 antibody was found over Sertoli cell lysosomes, but was absent from phagosomes formed after phagocytosis of spermatid residual bodies in the apical Sertoli cell cytoplasm in stages VIII and early IX of the cycle of the seminiferous epithelium. The phagosomes found later in the basal Sertoli cell cytoplasm in stages IX and X of the cycle became labeled with the antibody as the components of the residual bodies rapidly underwent lysis and disappeared from the Sertoli cells. Sertoli cell lysosomes isolated by cell fractionation (estimated purity of 80%) were found to contain a 65 kDa form of SGP‐1 or prosaposin, as well as the 15 kDa polypeptides or saposins. Thus, it appears that this unique lysosomal form of SGP‐1 reached the Sertoli cell phagosomes and that their derived polypeptides, the saposins, must play a role in the hydrolysis of membrane glycolipids found in phagocytosed residual bodies. © 1995 Wiley‐Liss, Inc.
Calcium and meiotic maturation of the mammalian oocyte
Authors: Homa Sheryl T. 
Published: February 2005

AbstractThe role of calcium in the regulation of both the meiotic and mitotic cell cycles has been the subject of considerable investigation in the nonmammalian field. In contrast, the mechanisms for signalling meiotic maturation in the mammalian oocyte are not as well documented nor as clearly defined. In the mammalian oocyte, calcium is associated with both spontaneous and hormone‐induced meiotic maturation. A transient release of endogenously stored calcium precedes germinal vesicle breakdown and can override cyclic AMP maintained meiotic arrest; it thus may signal the resumption of meiosis. Additionally, extracellular calcium is apparently required for meiotic progression past metaphase I. The time sequence for meiotic resumption and progression is very varied between species. The timing of cell cycle protein synthesis during meiosis suggests that cyclins may be expressed in oocytes of some species much earlier in their development than in others. A generic model is proposed for the mechanism for triggering meiotic resumption in the mammalian oocyte. In this model, the critical components of meiotic resumption involve the temporal relationship of cyclin synthesis and the subsequent activation of the MPF complex by the calcium signal generated, which accounts for differences among species. © 1995 Wiley‐Liss, Inc.
Inhibition of rabbit sperm acrosomal enzymes by gossypol
Authors: Yuan Y. Y. , Shi Q. X. , Srivastava P. N. 
Published: February 2005

AbstractThe effect of gossypol on the activities of 10 acrosomal enzymes of the rabbit sperm was evaluated. Acrosin, Azocoll proteinase, neuraminidase, and arylsulfatase were significantly inhibited or completely inactivated by 12–76 μM gossypol. Hyaluronidase, β‐glucuronidase, and acid phosphatase were inhibited only at a higher concentration of gossypol (380 μM). Phospholipase C, alkaline phosphatase, and β‐N‐Acetyl glucosaminidase were not inhibited even at 380 μM gossypol. Gossypol was found to be a noncompetitive inhibitor of arylsulfatase with a Ki of 120 μM. The inhibition was reversible and dose‐dependent. As the acrosomal enzymes were more sensitive to the inhibition by gossypol compared to sperm enzymes involved in glycolysis or energy production, these assays may serve as a more reliable indicator for monitoring the occurence of gossypol‐induced sterility. © 1995 Wiley‐Liss, Inc.
Changes in dopamine uptake and developmental effects of dopamine receptor inactivation in the sea urchin
Authors: Carginale Vincenzo , Borrelli Lucia , Capasso Antonio , Parisi Elio 
Published: February 2005

Abstract[3H]‐dopamine ([3H]‐DA) uptake was measured in the presence or absence of the catecholamine uptake inhibitor nomifensine in both unfertilized and fertilized eggs. Specific [3H]‐DA uptake depended on time and [3H]‐DA concentration; it was high in unfertilized eggs, declined 20–30 min after fertilization, and rose again during cleavage. Irreversible inactivation of dopamine receptors by N‐ethoxycarbonyl‐2‐ethoxy‐1,2‐dihydroquinoline (EEDQ) resulted in a complete loss of sensitivity of egg adenylate cyclase to dopamine stimulation. In fertilized eggs treated with EEDQ for 1 hr, restoration of adenylate cyclase activity sensitive to dopamine stimulation could be observed 4 hr after the end of treatment, thus suggesting the appearance of new dopamine receptors in cleaving eggs. Short‐term EEDQ treatment on unfertilized eggs, although not impairing fertilization, resulted in cleavage inhibition; the same treatment carried out soon after fertilization, on the other hand, elicited no effect on development. On the contrary, in embryos subjected to continuous treatment with EEDQ, development was impaired independent of the stage at which the treatment was started. © 1995 Wiley‐Liss, Inc.
The baboon expresses the calbindin‐D9k gene in intestine but not in uterus and placenta: Implication for conservation of the gene in primates
Authors: Jeung Eui‐Bae , Fan Nancy C. , Leung Peter C. K. , Herr John C. , Freemerman Alex , Krisinger John 
Published: February 2005

AbstractExpression of the Calbindin‐D9k (CaBP‐9k) gene was studied in the baboon. Northern blot analysis using a human CaBP‐9k cDNA probe detected expression in duodenum but not in uterus and placenta. Reverse transcription/polymerase chain reaction (RT/PCR) confirmed this expression pattern and indicated a high degree of identity between the baboon and human CaBP‐9k mRNAs. PCR was employed to amplify the intron A region of the baboon CaBP‐9k gene using human‐derived primers and baboon genomic DNA. The baboon intron was closely related to the human CaBP‐9k intron A, including the presence a complete Alu‐repetitive element. Most significantly, a 13 nucleotide long element at the 5′ end of the baboon intron matched exactly the human sequence. This element represents a nonfunctional variation of an estrogen response element found at the same location in the rat CaBP‐9k gene. The rat element functions as an enhancer and mediates uterine and possibly placental CaBP‐9k expression in the rat and probably most other mammals. The finding of a modified ERE in baboon as in human suggests that during primate evolution the expression of this mammalian‐specific gene has been eliminated in uterus and placenta. This scenario raises the question of the role of CaBP‐9k in these reproductive tissues. © 1995 Wiley‐Liss, Inc.
Identification of an Mr 60,000 polypeptide unique to the meiotic spindle of the mouse oocyte
Authors: Sobel J. Sabina , Pinto‐Correia Clara , Goldstein Elaine G. 
Published: February 2005

AbstractThe mouse oocyte expresses an Mr 60,000 (p60) polypeptide that is associated with the first and second meiotic spindles. Immunoreactive p60 was not detectable in the meiotic spindles of male germ cells or in mitotic spindles. P60 was identified with a polyclonal antibody whose predominant activity is directed against ankyrin. However, immunoadsorption experiments demonstrated that p60 is not an ankyrin isoform and represents a secondary activity of the polyclonal antibody. Circumstantial evidence suggest that p60 may be a micro‐tubule‐associated protein. Since the most obvious difference between the female meiotic spindle and other spindles is the long half‐life of the former, we hypothesize that p60 may function in the maintenance of the long‐lived female meiotic apparatus. © 1995 Wiley‐Liss, Inc.
Evidence that XR family interspersed RNA may regulate translation in Xenopus oocytes
Authors: Liu Chengyu , Smith L. Dennis 
Published: February 2005

AbstractIt has been shown that about two thirds of Xenopus oocyte or sea urchin egg cytoplasmic poly(A)+ RNA contains interspersed repetitive sequences. The functional significance of this interspersed RNA has remained unknown. Here the function of a subfamily of interspersed RNA (XR family; McGrew and Richter, 1989: Dev Biol 134:267–270) in Xenopus oocytes was studied. We found that the elimination of T7 XR (one of the two complementary strands of the XR repeat) interspersed RNA by complementary oligodeoxynucleotides significantly inhibited protein synthesis. On the other hand, the injection of in vitro synthesized T7 XR RNA stimulated translation. Moreover, the insertion of the T7 XR RNA sequence into globin mRNA repressed the translation of the globin mRNA. In order to explain these results, we analyzed interactions between the XR interspersed RNA and oocyte proteins. We found that the major XR RNA binding proteins were p56 and p60, which could be the known mRNA “masking” proteins that bind mRNA and inhibit translation. Further, a 42 kD protein has been identified that appears to bind T7 XR RNA relatively specifically, although it interacts with mRNA with a lower affinity. Based on all of these data, we have proposed that interspersed RNA may be involved in regulating translation by competing with mRNA to interact with certain proteins that can regulate translation. © 1995 Wiley‐Liss, Inc.
Intracellular pH of bovine sperm increases during capacitation
Authors: Vredenburgh‐Wilberg W. L. , Parrish J. J. 
Published: February 2005

AbstractThe effect of heparin‐induced capacitation on the intracellular pH (pHi) of individual bovine sperm was determined with image analysis. Sperm were loaded with the acetoxymethyl ester of the pH sensitive fluorescent indicator, 2′,7′‐bis(carboxyethyl)‐5(6)‐carboxy‐fluorescein (BCECF). The pHi of 5303 sperm was evaluated from a total of five bulls at .5, 2, 3, 4, and 5 h of incubation. The pHi did not differ between the sperm head and mid‐piece (P > 0.05). An increase in sperm head pHi was seen in heparin‐treated sperm at 3, 4, and 5 h of incubation relative to sperm incubated without heparin (control, P < 0.05). At 5 h of incubation, the pHi in heparin‐treated sperm was 6.92 ± 0.07, while control‐treated sperm pHi was 6.70 ± 0.03. Initially a normal frequency distribution was seen for sperm pHi in both heparin‐ and control‐treated sperm. As the incubation progressed, the frequency distribution began to skew towards higher pHi in both samples but was more dispersed for the heparin‐treated sperm. Following an NH4Cl‐induced alkaline load, the pHi of both control‐ and heparin‐treated sperm recovered toward the resting pHi with a half‐time of recovery of 1.5–1.7 min. The recovery of sperm pHi was not due to leakage of NH4+ into sperm because recovery also occurred with trimethylamine. The instantaneous velocity of the pHi recovery (vi) was dependent on pHi and decreased as pHi decreased. Capacitation by heparin was associated with an 81% decrease in vi at a pHi of 7.00, but there was no effect of capacitation on the proton buffering power of the sperm, which was 87 ± 8 mM/pH unit. Results demonstrate that both the regulation of pHi and resting pHi were altered during capacitation of bovine sperm by heparin. © 1995 Wiley‐Liss, Inc.
Isolation of cDNAs from maternal mRNAs specifically present during early development
Authors: Moreau Jacques , Iouzalen Nathalie , Mechali Marcel 
Published: February 2005

AbstractIn many animals the regulation of early embryonic development is under the control of mRNAs of maternal origin. We describe here the construction and characterization of a subtractive cDNA library to isolate genes whose expression is restricted to early development. Such genes might be potentially involved in developmental diseases, if accidentally expressed during adult life. Seven yet unknown genes preferentially expressed in the oocyte and present during early development were isolated from this library by differential screening. Their transcription patterns provide evidence for a selective expression during oogenesis and the existence of a gene family specifically implicated in functions linked to early embryogenesis. © 1995 Wiley‐Liss, Inc.
Oxytocin induced a biphasic increase in the intracellular Ca2+ concentration of porcine myometrial cells: Participation of a pertussis toxin—insensitive G‐protein, inositol 1,4,5‐trisphosphate—sensitive Ca2+ pool, and Ca2+ channels
Authors: Zhuge Ronghua , Li Siben , Chen Ter‐Hsin , Hsu Walter H. 
Published: February 2005

AbstractThis study investigated the underlying mechanisms of oxytocin (OT)‐induced increases in intracellular Ca2+ concentrations ([Ca2+]i) in acutely dispersed myometrial cells from prepartum sows. A dosedependent increase in [Ca2+]i was induced by OT (0.1 nM to 1 μM) in the presence and absence of extracellular Ca2+ ([Ca2+]e). [Ca2+]i was elevated by OT in a biphasic pattern, with a spike followed by a sustained plateau in the presence of [Ca2+]e. However, in the absence of [Ca2+]e, the [Ca2+]i response to OT became monophasic with a lower amplitude and no plateau, and this monophasic increase was abolished by pretreatment with ionomycin, a Ca2+ ionophore. Administration of OT (1 μM) for 15 sec increased inositol 1,4,5‐trisphosphate (IP3) formation by 61%. Pretreatment with pertussis toxin (PTX, 1 μg/ml) for 2 hr failed to alter the OT‐induced increase in [Ca2+]i and IP3 formation. U‐73122 (30 nM to 3 μM), a phospholipase C (PLC) inhibitor, depressed the rise in [Ca2+]i by OT dose dependently. U‐73122 (3 μM) also abolished the OT‐induced IP3 formation. Thapsigargin (2 μM), an inhibitor of Ca2+‐ATPase in the endoplasmic reticulum, did not increase [Ca2+]i. However, it did time‐dependently inhibit the OT‐induced increase in [Ca2+]i. Nimodipine (1 μM), a Voltage‐dependent Ca2+ channel (VDCC) blocker, inhibited the OT‐induced plateau by 26%. La3+ (1 μM), a nonspecific Ca2+ channel blocker, abrogated the OT‐induced plateau. In whole‐cell patch‐clamp studies used to evaluate VDCC activities, OT (0.1 μM) increased Ca2+ Current (Ica) by 40% with no apparent changes in the current‐voltage relationship. The OT‐induced increase in Ica reached the maximum in 5 min, and the increase was abolished by nimodipine (1 μM). These results suggested that (1) activation of OT receptors in porcine myometrium evokes a cascade in the PTX‐insensitive G‐protein–PLC‐IP3 signal transduction, resulting in an increase in [Ca2+]i; (2) the OT‐induced increase in [Ca2+]i is characterized by a biphasic pattern, in which the spike is predominately contributed by the intracellular Ca2+ release from the IP3‐sensitive pool, and to a lesser extent by Ca2+ influx, whereas the plateau is from increased Ca2+ influx; and (3) the influx is via VDCC and receptor‐operated Ca2+ channels. © 1995 Wiley‐Liss, Inc.
Transient appearance of CRES protein during spermatogenesis and caput epididymal sperm maturation
Authors: Cornwall Gail A. , Hann Stephen R. 
Published: February 2005

AbstractIn previous studies we identified an epididymal gene that exhibits homology to the cystatin family of cysteine protease inhibitors. The expression of this gene, termed CRES (cystatin‐related epididymal and spermatogenic), was shown to be highly restricted to the proximal caput epididymal epithelium with less expression in the testis and no expression in the 24 other tissues examined. In this report, studies were carried out to examine CRES gene expression in the testis as well as to characterize the CRES protein in the testis and epididymis. In situ hybridization experiments revealed that within the testis CRES gene expression is stage‐specific during spermatogenesis and is exclusively expressed by the round spermatids of Stages VII‐VIII and the early elongating spermatids of Stages IX and X. Immunohistochemical studies demonstrated that CRES protein was transiently expressed in both the testis and epididymis. Within the testis the protein was localized to the elongating spermatids, whereas within the epididymis CRES protein was exclusively synthesized by the proximal caput epithelium and then secreted into the lumen. Surprisingly, the secreted CRES protein had completely disappeared from the epididymal lumen by the distal caput epididymidis. Western blot analysis of testicular and epididymal proteins showed that the CRES antibody specifically recognized a predominant 19 kDa CRES protein and a less abundant 14 kDa form. These observations suggest that the CRES protein performs a specialized role during sperm development and maturation. © 1995 Wiley‐Liss, Inc.
Characterization of alternatively spliced human SP‐10 mRNAs
Authors: Freemerman Alex J. , Flickinger Charles J. , Herr John C. 
Published: February 2005

AbstractAlternatively spliced mRNAs encoding the human intraacrosomal protein SP‐10 were sought by the reverse transcriptase polymerase chain reaction (RTPCR). Eleven RTPCR products were identified, characterized, and found to represent authentic alternatively spliced SP‐10 mRNAs. The 11 alternatively spliced SP‐10 mRNAs encoded proteins ranging from 81 to 265 amino acids. The 10 smaller variants all resulted from one or two in‐frame deletions in exons 2 and/or 3 of the SP‐10 genomic sequence. Quantitative competitive RTPCR showed that the four largest SP‐10 mRNAs represented the majority (>99%) of the SP‐10 message in testes from each of four men. The relative abundance of each of the four SP‐10 mRNAs varied between individuals, but the longest SP‐10 mRNA, SP10‐1, which encoded a 265 amino acid protein, was consistently the most abundant, comprising 53–72% of the total SP‐10 message. This was followed by the second largest SP‐10 mRNA, SP10‐2, which encoded a protein of 246 amino acids and comprised 15‐32%. The third and fourth largest SP‐10 mRNAs, SP10‐3 and SP10‐4, encoded proteins of 210 and 195 amino acids and accounted for 3.4–8.3% and 8.7–12.5% of the total SP‐10 messages, respectively. The remaining 7 SP‐10 mRNAs combined accounted for<1% of the total SP‐10 message. Within the low abundance group of mRNAs were two that deleted the entire third exon of SP‐10. The present study suggests that phenomena of cryptic splicing and exon skipping occur within the SP‐10 mRNA. Along with proteolysis, alternative splicing also helps to explain the heterogeneous forms of SP‐10 that have been observed on Western blots of human sperm extracts. © 1995 Wiley‐Liss, Inc.
Homeobox gene expression in human oocytes and preembryos
Authors: Verlinsky Yury , Morozov Gennedy , Gindilis Viktor , Strom Charles M. , Freidin Michael , Rechitsky Svetlana , Verlinsky Oleg , Ivakhnenko Victor , Zdanovsky Valery , Kuliev Anver 
Published: February 2005

AbstractHomeobox gene expression in human preimplantation development has not been established. We used reverse transcriptase‐polymerase chain reaction (RT‐PCR) with intron spanning primer sets to investigate the presence of mRNA of homeobox genes in human oocytes and preembryos. RT‐PCR products obtained from normal and unfertilized oocytes, from cleaving normal and triploid embryos, and from morulae and blastocysts were cloned, sequenced, and analyzed for the presence of homeobox sequences. The presence of mRNA of homeoboxes HoxA4 and HoxA7 was demonstrated; HoxA4 was present in normal and unfertilized oocytes and also in a 4‐cell embryo. HoxA7 was present in normal oocytes and cleaving triploid embryos. © 1995 Wiley‐Liss, Inc.