Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.2.1.23 (beta-galactosidase)
14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Examination of the role of carbohydrates in specific recognition between spermatozoa and zona pellucida has focussed on understanding the interaction of sperm hydrolases or lectin-like molecules with zona pellucida ligands. To elucidate the role of specific spermatozoan hydrolases in gamete interaction, rabbit testis beta-galactosidase and arylsulfatase A were purified, characterized, and localized in spermatozoa. beta-Galactosidase and arylsulfatase A co-purified after affinity, size, or reverse-phase chromatography. N-Terminal amino acid analysis and enzymatic characterization suggested that neither enzyme is a testis-specific isozyme. Size chromatography indicated that both enzymes aggregated into macromolecular complexes at pH 4.0, while both dissociated at pH 8.0. beta-Galactosidase and arylsulfatase A co-localized on the sperm surface and in the acrosome and postacrosomal regions of spermatozoa. Throughout the zona-induced acrosome reaction, both enzymes remained associated with the detached acrosomal cap and postacrosomal region of acrosome-reacted spermatozoa. Because the acrosome is an acidic subcellular compartment, internal beta-galactosidase and arylsulfatase A are probably aggregated in acrosome-intact spermatozoa and dissociate as they are exposed to pH increases during the acrosome reaction.
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PMID:Characterization of rabbit testis beta-galactosidase and arylsulfatase A: purification and localization in spermatozoa during the acrosome reaction. 135 47

There are two isozymes of angiotensin-converting enzyme (ACE), one produced by somatic tissues and a smaller protein synthesized by developing spermatozoa (testis ACE). To investigate the molecular control of testis ACE, we generated mice transgenic for a construct containing a putative testis-specific ACE promoter linked to the Escherichia coli reporter gene encoding beta-galactosidase. The transgenic mice express beta-galactosidase protein and RNA only within the testis. Histochemical analysis of the transgenic mice shows co-localization of beta-galactosidase protein and endogenous ACE within elongating spermatozoa. These studies demonstrate that transcription of testis ACE is controlled by a strong intragenic testis-specific promoter that is contained within a 698-base pair fragment immediately upstream from the transcription start site of testis ACE. Characterization of the testis ACE promoter may provide insights into the molecular mechanisms controlling cell stage-specific gene expression in the male germ line.
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PMID:Transgenic mice demonstrate a testis-specific promoter for angiotensin-converting enzyme. 165 14

The janus locus of Drosophila melanogaster displays a very unusual organization. It comprises two partially overlapping genes, janA and janB, which are transcribed in the same orientation; the start of transcription of janB, the downstream gene, is located in the 3' exonic region of janA. Both genes are expressed during spermatogenesis. Transcription of janB is restricted to this developmental process, whereas janA is ubiquitously transcribed in both the somatic and germinal tissues of males and females. In order to delimit the cis-acting sequences regulating the transcription of janB, the expression of four chimeric janB-lacZ genes was examined in transgenic lines by Northern blot analysis, in situ hybridization and in situ histochemical staining for beta-galactosidase activity. Results showed that the testis-specific expression of the janB gene is mediated by a short DNA sequence (positions -174 to +107) which is located entirely within the last exon of the upstream janA gene. The tissue specificity of the expression of the janB gene is maintained when most of the janA coding and upstream sequences are deleted. Yet the presence in cis of an active janA gene leads to reduced accumulation of the janB-lacZ hybrid mRNA. This supports the hypothesis that janA transcription interferes with the function of the janB cis-regulatory elements. Our results also demonstrate that the 5' untranslated leader of the janB mRNA contains translational cis-acting elements, which completely block the translation of the janB-lacZ transcripts during the premeiotic stages of sperm development. A janB-lacZ construct was used to examine the sexual phenotype of the germline cells of masculinized XX transformer-2 (tra-2) flies. This has enabled us to confirm at the molecular level previous observations that the germline cells of these flies can enter the spermatogenic pathway of differentiation.
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PMID:Transcriptional and translational cis-regulatory sequences of the spermatocyte-specific Drosophila janusB gene are located in the 3' exonic region of the overlapping janusA gene. 212 14

Investigation of an enhancer-trap line exhibiting testis-specific beta-galactosidase expression led to the isolation of the Drosophila gene encoding inosine monophosphate dehydrogenase (IMPD), the rate-limiting enzyme in guanine nucleotide synthesis, which has been implicated in cell cycle control and malignant transformation. Northern and in situ hybridization analysis demonstrated that the gene has a complex expression pattern involving several independently regulated transcripts. Two ubiquitous, but highly ovary enriched, transcripts of 2.5 and 1.9 kb are expressed in the nurse cells and delivered to the oocyte, whilst a 0.9 kb transcript is found exclusively in the testis. The 2.5 kb transcript encodes a 58 kDa protein, which is highly similar in length and sequence to mouse and human IMPDs and is presumably required for GTP synthesis during early embryogenesis. Over-expression of this cDNA in Escherichia coli yielded a product of the predicted size, which was demonstrated to possess IMPD activity in a spectrophotometric assay. The coding capacity of the other transcripts is currently uncertain. We present evidence that IMPD is the product of the raspberry (ras) locus at 9E and the functions of the gene are discussed in relation to the phenotypes of ras mutants.
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PMID:The raspberry locus encodes Drosophila inosine monophosphate dehydrogenase. 747 79

A 42-kilobase pair region of rat DNA containing the Ca2+/calmodulin-dependent protein kinase IV (CaM kinase IV) gene has been cloned and characterized. The gene consists of 12 exons and 11 introns and is predicted to encode both beta and alpha forms of CaM kinase IV as well as the testis-specific calmodulin-binding protein calspermin. The promoter utilized to generate the alpha-kinase isoform is located in intron 1, whereas the promoter utilized to produce the calspermin transcript is contained in intron 10. The calspermin promoter region which extends from -200 to +321 relative to the calspermin transcription initiation site that contains two cyclic AMP response elements (CRE) at -70 and -50 and has been shown previously to be inactive in NIH3T3 cells (Sun, Z., Sassone-Corsi, P., and Means, A. R. (1995) Mol. Cell. Biol. 15, 561-571) was ligated to the lacZ reporter gene and used to generate transgenic mice. The promoter was expressed exclusively in postmeiotic testis where beta-galactosidase was found predominantly in elongating spermatids. The cell and developmental specificity of transgene expression was very similar to the pattern shown by the endogenous gene. Although the transgene promoter was silent in somatic tissues, beta-galactosidase expression could be restored in primary cultures of skin fibroblasts by introduction of vectors encoding CREM tau and CaM kinase IV.
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PMID:Organization and analysis of the complete rat calmodulin-dependent protein kinase IV gene. 749 91

Components of the mammalian sperm acrosome that have been conserved during evolution are probably essential for fertilization and are therefore potential antigens for the development of an immunocontraceptive vaccine. In order to identify such protein components, a series of specific polyclonal antisera were generated by immunizing rabbits with purified acrosomal membrane fractions from hamster epididymal spermatozoa. Antisera were finally selected using immunological and in-vitro fertilization assays, and used to then screen a human testis lambda gt11 cDNA library. As a result of this screening over 70 clones were identified, selected and purified. The cDNAs were amplified by polymerase chain reaction (PCR) and the inserts characterized by restriction enzyme digestion and oligonucleotide probing techniques. The functional activity beta-galactosidase fusion proteins expressed by these clones (HA5-2, HA6-2 and HB4-1) inhibited significantly fertilization and reduced spermatozoa binding compared to controls. To date, sequence data has been obtained from HB4-1 (1.75 kb). The first 1132 nucleotides displayed > 96% homology to human testis-specific lactate dehydrogenase (LDH-C4) gene, the product of which is a known candidate antigen for a contraceptive vaccine. This finding suggests that a strategy involving the screening across species for conserved moieties of the mammalian acrosome may be useful for identifying candidate antigens for immunocontraception.
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PMID:A strategy for identifying candidate sperm antigens for immunocontraception: isolation of human testis cDNA clones using polyclonal antisera directed against hamster acrosomal membrane preparation. 755 86

In order to study the temporal and spatial regulation of a rat testis-specific heat-shock-like hst70 gene, an 0.8-kb fragment of its upstream DNA was fused to the lacZ gene and microinjected into one-cell murine embryos. Independent tgHST1 and tgHST2 transgenic mice strains were established, containing about 5-7 and 40-60 transgene copies/haploid genome, respectively. Enzyme assays in various tissues showed that transgene-encoded beta-galactosidase accumulates exclusively in testes of transgenic animals and cannot be detected until 16-17 days after birth. In-situ assays revealed that the enzyme accumulates mainly in pachytene primary spermatocytes. Our data complement previous studies on the endogenous rat hst70 and suggest that its 0.8-kb upstream region contains sufficient information to function as an active spermatogenesis-specific promoter.
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PMID:An upstream region of the rat spermatogenesis-specific heat-shock-like Hst70 gene confers testis-specific expression in transgenic mice. 844 52

Murine c-mos transcripts isolated from testes have 5'-untranslated regions (5'UTRs) of approximately 300 nucleotides with a series of four overlapping open reading frames (ORFs) upstream of the AUG codon that initiates the Mos ORF. Ovarian c-mos transcripts have shorter 5'UTRs (70-80 nucleotides) and contain only 1-2 of the upstream ORFs (uORFs). To test whether these 5'UTRs affect translational efficiency, we have constructed plasmids for the expression of chimeric transcripts with a mos-derived 5'UTR fused to the Escherichia coli beta-galactosidase coding region. Translational efficiency has been evaluated by measuring beta-galactosidase activity NIH3T3 cells transiently transfected with these plasmids and with plasmids where various mutations have been introduced into the 5'UTR. We show that the 5'UTR characteristic of testis-specific c-mos mRNA strongly represses translation relative to the translation of transcripts that contain a 5'UTR derived from beta-globin mRNA, and this is mainly due to the four uORFs. Each of the four upstream AUG triplets can be recognized as a start site for translation, and no single uAUG dominates the repressive effect. The uORFs repress translation by a mechanism that is not affected by the amino acid sequence in the COOH-terminal region of the uORF-encoded peptides. The very short uORF (AUGUGA) present in ovary-specific transcripts does not repress translation. Staining of testis sections from transgenic mice carrying chimeric beta-galactosidase transgene constructs, which contain a mos 5'UTR with or without the uATGs, suggests that the uORFs can dramatically change the pattern of expression in spermatogenic cells.
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PMID:Elements in the murine c-mos messenger RNA 5'-untranslated region repress translation of downstream coding sequences. 889 45

The Drosophila center divider gene (cdi) was isolated in an enhancer trap screen undertaken to identify genes involved in embryonic central nervous system (CNS) midline cell development. Three independent lines with P-element insertions at 91F were analyzed that all showed prominent beta-galactosidase expression in the CNS midline precursor cells and other cell types. Null mutations were created by imprecise P-element excision and shown to be larval lethal, although no severe CNS defects were observed in mutant embryos. The DNA surrounding the sites of insertion was cloned and found to contain a transcription unit that was dynamically expressed in a pattern corresponding to the enhancer trap line beta-galactosidase expression. Sequencing of cDNA clones revealed that the cdi gene encodes a 1140-amino acid protein that is an ortholog of the mammalian testis-specific TESK1 protein kinase. This serine/threonine kinase is distinct from other protein kinases because of sequence differences in the residues conferring substrate specificity. The unique sequence is conserved in Cdi, suggesting that Cdi/TESK1 represents a novel class of signaling proteins.
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PMID:Drosophila center divider gene is expressed in CNS midline cells and encodes a developmentally regulated protein kinase orthologous to human TESK1. 1039 Jan 52

Transgenic mice carrying the coding sequence of beta-galactosidase, for which expression was driven by various upstream regions including the transcription promoter of the testis-specific mouse Pgk-2 gene, were generated. Expression of beta-galactosidase mRNA driven by the region between nucleotide positions -1404 and +61, with respect to the transcription initiation site numbered +1, was examined by reverse transcription-mediated polymerase chain reaction, blot hybridization and in situ hybridization, and compared with that of endogenous Pgk-2 mRNA. The results revealed that the 1.4kb DNA region is sufficient for determining the organ-specific, developmental stage-specific and spermatogenic stage-specific transcription of the mouse Pgk-2 gene. When the region between -684 and +61 was used to generate transgenic mice, beta-galactosidase mRNA was detectable not only in the testis, but also in other organs such as brain and lung. However, the timing and cell-type specificity of testicular expression of beta-galactosidase mRNA were retained in these mice. Because the region between -1404 and -685 repressed the Pgk-2 promoter in somatic cell-derived cell lines, it is suggested that the organ specificity of Pgk-2 transcription is achieved at least partly by negative regulation.
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PMID:Ectopic activation of the transcription promoter for the testis-specific mouse Pgk-2 gene on elimination of a cis-acting upstream DNA region. 1096 38


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