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)

Heterozygote detection for angiokeratoma corporis diffusum (Anderson-Fabry disease, ACD), an X-linked disorder of glycosphingolipid metabolism was examined using alpha-galactosidase activity, an alpha-galactosidase/beta-galactosidase activity ratios (alpha/beta ratio) in leucocytes, plasma, and hair follicles; For leucocytes, 22 obligate heterozygotes, 25 suspected heterozygotes, and 47 control subjects were studied, while for plasma, the groups were 17 obligate heterozygotes and 35 controls. The alpha/beta ratio in plasma and leucocytes was clearly a better discriminator between obligate heterozygotes and controls than alpha-galactosidase activity alone, but still failed to detect 3 obligates with leucocytes and 2 with plasma. Discrimination was not improved by joint use of plasma and leucocyte alpha/beta ratios, but was improved by measurement of hair-follicle alpha/beta ratios. The interdecile range of log (alpha-galactosidase/beta-galactosidase activity) in 20 hair follicles from each of 4 obligate and 7 suspected heterozygotes was clearly different from 11 control subjects. Accordingly, for rapid screening for carriers of ACD, we recommend use of leucocyte or plasma alpha/beta ratios which should detect greater than 85% of heterozygotes. When results are equivocal, and ancillary information suggests heterozygous status, the more time-consuming measurement of hair-follicle alpha/beta ratios is a useful additional test.
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PMID:Heterozygote detection in angiokeratoma corporis diffusum (Anderson-Fabry disease). Studies on plasma, leucocytes, and hair follicles. 40 11

In Fabry disease, as in other X-linked traits, identification of all heterozygotes is difficult. Reduced plasma alpha-galactosidase activities will correctly identify 60-70% of the carriers. The identification rate improves when an alpha/beta-galactosidase activity enzyme ratio is used. We measured alpha-galactosidase activity in reference to several other enzyme activities, beta-galactosidase, beta-hexosaminidase, and alpha-fucosidase in plasma and leukocytes from 22 suspected and 9 obligate carriers from 4 kindreds of Fabry disease patients. Utilizing such ratios or various combinations of ratios in plasma we have correctly identified the carrier state in 91% of heterozygotes. Leukocyte alpha/beta-galactosidase identified one more female than leukocyte alpha-galactosidase activities alone. We recommend the use of such multiple biochemical tests to identify carriers of Fabry disease.
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PMID:Heterozygote detection in Fabry disease utilizing multiple enzyme activities. 627 91

X chromosome inactivation (XCI) has been assumed to be complete in all cells of female mouse embryos at about 6 d post coitum (dpc). However, a recent study on beta-galactosidase expression of an X-linked lacZ transgene suggests that XCI is probably not complete several days after this time in some lineages. To help resolve this issue, we analysed XCI in embryos which carry the T(X;16)16H (Searle's) translocation and are heterozygous at the X-linked Hprt and Pgk-1 genes. The quantitative RT-PCR single nucleotide primer extension (SNuPE) assay was used to measure Hprt and Pgk-1 allele-specific transcripts in embryos 9.5 dpc. No transcripts from the normal X chromosome were found in any of the tissues tested, indicating that inactivation was complete for these endogenous genes.
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PMID:Mouse endogenous X-linked genes do not show lineage-specific delayed inactivation during development. 761 59

The haematopoietic development of embryonic stem (ES) cell injection chimaeras was analysed using beta-galactosidase expression from an X-linked transgene as a marker to distinguish the ES-derived cell population from the host cells. The number of cells in the different haematopoietic cell subpopulations was determined by flow cytometry. When the proportions of ES-derived cells in the antigen-positive lineages were compared to the ES cell contribution to all cells in teh organs, we found an unexpected bias in the haematopoietic differentiation of ES-derived cells. ES descendants were overrepresented in the bone marrow B lymphoid cell population and the splenic myeloid cells but were underrepresented in the CD4-positive T lymphoid cells in the spleen. These results were obtained by comparison with control female animals that were X chromosome mosaic for beta-galactosidase expression. These findings of uneven contribution to haematopoietic development by ES cells indicate that the commitment of ES cell descendants may be different from that of the host cells.
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PMID:The development of haematopoietic cells is biased in embryonic stem cell chimaeras. 764 91

X-chromosome activity in female mouse embryos was studied at the cellular level using an X-linked lacZ transgene which encodes beta-galactosidase (beta-Gal). Translation of maternal RNA in oocytes is seen as beta-Gal activity that persists into early cleavage-stages. Zygotic transcription of the transgene from the maternal X chromosome (Xm) is first found at about the 8-cell stage. By contrast, expression of the lacZ transgene on the paternal X chromosome (Xp) is not seen until later at the 16-32-cell stage. Preferential inactivation of Xp occurs in the mural trophectoderm, the primitive endoderm, and derivatives of the polar trophectoderm, but a small number of cells in these lineages may still retain an active paternal X chromosome. X inactivation begins at 3.5 days in the inner cell mass but contrary to previous findings the process is not completed in the embryonic ectoderm by 5.5 to 6.0 days. Regional variation in beta-Gal activity is also observed in the embryonic ectoderm during gastrulation which may be related to the specification of cell fates. Random inactivation of Xp and Xm ensues in all somatic tissues but the process is completed at different times in different tissues. The slower progression of X inactivation in tissues such as the notochord, the heart, and the embryonic gut is primarily due to the persistent maintenance of two active X chromosomes in a significant fraction of cells in these tissues. Recent findings on the methylation of endogenous X-linked genes suggest that the prolonged expression of beta-Gal might also be due to the different rate of spreading of inactivation along the X chromosome to the lacZ transgene locus in different tissues.
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PMID:Expression of an X-linked HMG-lacZ transgene in mouse embryos: implication of chromosomal imprinting and lineage-specific X-chromosome activity. 783 9

The period (per) gene is located on the X chromosome of Drosophila melanogaster. Its expression influences biological clocks in this fruit fly, including the one that subserves circadian rhythms of locomotor activity. Like most X-linked genes in Drosophila, per is under the regulatory control of gene dosage compensation. In this study, we assessed the activity of altered or augmented per+ DNA fragments in transformants. Relative expression levels in male and female adults were inferred from periodicities associated with locomotor behavioral rhythms, and by histochemically assessing beta-galactosidase levels in transgenics carrying different kinds of per-lacZ fusion genes. The results suggest that per contains multipartite regulatory information for dosage compensation within the large first intron and also within the 3' half of this genetic locus.
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PMID:Dosage compensation of the period gene in Drosophila melanogaster. 785 69

Pgk-1 is an X-linked gene encoding 3-phosphoglycerate kinase, an enzyme necessary in every cell for glycolysis. The regulatory sequences of the Pgk-1 gene were used to drive the E. coli lacZ reporter gene and 2 strains of transgenic animals created with this Pgk-lacZ transgene carried on autosomes. The levels of expression of Pgk-1 varied from one adult tissue to another and the transgene was similarly regulated. However, in situ staining of the beta-galactosidase encoded by the transgene indicated extensive cell-to-cell variability in its level of expression. A reproducible subset of cells stained darkly for the transgene product. Some of these beta-galactosidase positive cells were rapidly proliferating while others appeared to be metabolically very active, suggesting that the Pgk-1 promoter is regulated so as to be more active in cells requiring high levels of glycolysis. Although Pgk-1 is X-linked and subject to X chromosome inactivation, the transgenes were not inactivated in either female somatic or male germ cells. Thus, the Pgk-1 promoter drives transgene expression in all tissues but the levels of expression are not uniform in each cell.
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PMID:Murine PGK-1 promoter drives widespread but not uniform expression in transgenic mice. 799 75

During mammalian development, one of the two X chromosomes in female embryos is randomly inactivated in the somatic cell in order to achieve gene dosage compensation. But is X inactivation established simultaneously or is it accomplished over time in a lineage-dependent fashion? We have examined this question in mouse embryos carrying an X-linked lacZ transgene. This transgene is subject to inactivation and the loss of beta-galactosidase activity provides a direct indication of X inactivation in individual cells. We find that X inactivation proceeds with different schedules in different somatic tissues, and the notochord, the heart, cranial mesoderm and the hindgut are among the last tissues to undergo X inactivation.
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PMID:X-chromosome inactivation occurs at different times in different tissues of the post-implantation mouse embryo. 849 50

Differentiation of hematopoietic precursor cells results in the formation of clonally related descendent cells. Using the mosaic expression of beta-galactosidase in female mouse fetuses heterozygous for an X-linked lacZ transgene, we analyzed the clonal relationship of the hematopoietic progeny. The proportion of beta-galactosidase positive cells for different T- and B-lymphoid and myeloid cell populations was determined at different stages of fetal development. We found excellent correlations of the proportion of beta-galactosidase expressing cells for all hematopoietic lineages confirming that they share a common ancestry. Therefore, it was possible to estimate the number of common precursor cells (PC) based on binomial distribution and covariance analysis of pairs of different hematopoietic cell populations. Our results obtained from hematopoietic cells at 15.5 to 18.5 days of gestation indicated the presence of 15 to 18 lymphoid and 18 to 22 myeloid/lymphoid specific precursor cells. Statistical analysis of the precursor cell numbers showed a trend of increasing numbers that was highly significant. The precursor cell number was inversely related to maturity of the cell populations analyzed; ie, the lowest number of lymphoid and lymphoid/myeloid precursors was calculated when the most mature CD3+ T-cell population was used for comparison. Determination of PC numbers can therefore be used to assess the relative maturity and developmental potential of individual cell populations.
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PMID:Estimation of the number of hematopoietic precursor cells during fetal mouse development by covariance analysis. 883 42

Transglycolytic synthesis of 3'-sialyl-N-acetyllactosamine by sequential use of beta-galactosidase from Bacillus circulans and trans-sialidase from Trypanosoma cruzi was described. These reactions depicted the first complete synthesis of a biologically important oligosaccharide with high regioselectivity avoiding use of glycosyltransferases and NDP sugars.
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PMID:Complete synthesis of 3'-sialyl-N-acetyllactosamine by regioselective transglycosylation. 898 45


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