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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The role of carbohydrate in the structure and function of immuno-globulin Fc regions has been studied using the interaction of a monoclonal mouse IgG2b anti-NIP antibody with the IgG Fc transport receptor from neonatal rat gut. An aglycosyl variant of this immunoglobulin, in which site-directed mutagenesis had been used to eliminate the carbohydrate attachment site in the CH2 domain by changing Asn297 to Ala, was compared in this system to aglycosyl immunoglobulin prepared from immunoglobulin-secreting cells treated with tunicamycin to inhibit N-linked glycosylation. Loss of carbohydrate from the heavy chain was confirmed for both methods by Western blotting of the separated chains with Concanavalin A, and no significant differences in circular dichroism spectra were found between glycosylated and non-glycosylated mutants. Removal of carbohydrate by site-directed mutagenesis had no effect on binding of the immunoglobulin to the Fc transport receptor (FcTR) in vitro or transport from the gut to blood in vivo. Short-term clearance from circulation and degradation by gut contents in vitro were similarly unaffected. Mutation of Glu235 to Leu, an alteration that allows binding to human monocyte Fc gamma RI, did not alter the interaction with FcTR. However, treatment of wild-type or aglycosyl mutant cells with tunicamycin resulted in immunoglobulin which was less stable, cleared more rapidly and was transported slightly less efficiently. These findings indicate that the binding site for the FcTR may be unique among Fc-binding ligands, and that tunicamycin treatment may cause alterations in the immunoglobulin molecule in addition to loss of N-linked carbohydrate.
Mol Immunol
PMID:Interaction of aglycosyl immunoglobulins with the IgG Fc transport receptor from neonatal rat gut: comparison of deglycosylation by tunicamycin treatment and genetic engineering. 163 63

The phenotypic characterization and distribution of lymphocytes bearing the gamma/delta T-cell receptor (TCR) in the human gut were investigated by an immunohistochemical technique. A mirror section technique and double staining method were used for the phenotypic analysis. Intraepithelial delta-positive cells were almost all CD8-positive and rarely negative for both CD4 and CD8. On the other hand, lymphocytes bearing TCR gamma/delta in the lamina propria were largely negative for both CD4 and CD8. The ratio of delta-positive to CD3-positive cells amongst intraepithelial lymphocytes was larger in the lower intestine. Delta-positive cells were also observed in paracortical areas of lymphoid follicles. Immunoelectron microscopic observation revealed granular structures in these delta-positive cells, which are also present in large granular lymphocytes. The role of lymphocytes bearing TCR gamma/delta in mucosal immune responses in the human gut are discussed.
Virchows Arch B Cell Pathol Incl Mol Pathol 1991
PMID:Immunohistochemical characterization, distribution and ultrastructure of lymphocytes bearing the gamma/delta T-cell receptor in the human gut. 167 80

Ultrastructural aspects of the extracellular matrix (ECM) in the midaxial region of dysraphic embryos of the loop-tail (Lp) mutant mouse were analyzed by means of electron microscopy. In 17-23 somite embryos, ultrastructural differences in the ECM occurred with respect to the presence of a pair of long trailing basal laminar strands extending continuously from the ventral notochordal cells to the gut in abnormal (Lp/Lp) embryos, in contrast to short, ragged, discontinuous strands in normal (+/+; Lp/+) embryos. The ultrastructural localization and configuration of fibronectin (FN) and laminin (L) associated with these strands, however, were similar in normals and abnormals. In addition, FN occurred over interstitial bodies, fibrils, and sporadically along the basal laminae of the neural tube (or folds), notochord, gut, and vessels, whereas L was largely confined to the basal laminae. The results indicate that although the ultrastructural pattern of FN and L reactivity are similar in normal and abnormal embryos, a disturbance in the manner whereby the notochord detaches from the gut in dysraphic embryos may be of causal significance in the etiology of dysraphism in this mutant.
Virchows Arch B Cell Pathol Incl Mol Pathol 1991
PMID:Ultrastructural analysis of the midaxial extracellular matrix in spinal dysraphism. 167 7

The proto-oncogene fps/fes encodes a distinctive type of protein-tyrosine kinase. We identified a Drosophila gene (dfps85D) whose product resembles the proteins encoded by vertebrate fps/fes and the closely related gene fer. dfps85D is located at chromosomal position 85D10-13 and is unlikely to correspond to any previously defined genetic locus in Drosophila melanogaster. Expression of the gene is entirely zygotic in origin and occurs throughout the life cycle. But hybridization in situ revealed that the pattern of expression is specialized and evolves in a provocative manner. The most notable feature of expression is the diversity of developmental periods, tissues, and cells in which it occurs. In some tissues, expression is transient; in others, it is continuous. Expression occurs in both mitotic and terminally differentiated tissue and, at various times in development, is prominent in imaginal disks, gut, muscle, testes, ovaries, retina, and other neural tissues. It appears that the use of dfps85D is more diversified than that of other Drosophila protein-tyrosine kinases reported to date and contrasts sharply with the restricted expression of fps itself in vertebrates. The detailed description of expression provided here will help guide the search for mutants in dfps85D.
Mol Cell Biol 1991 Jan
PMID:A gene related to the proto-oncogene fps/fes is expressed at diverse times during the life cycle of Drosophila melanogaster. 189 62

The role of extracellular matrix (ECM) in the differentiation of tissue types was examined in embryos of Strongylocentrotus purpuratus. We have examined the expression of various tissue-specific molecular markers after disrupting the ECM by culturing embryos in the presence of beta-aminoproprionitrile fumarate (BAPN), which disrupts collagen deposition, and beta-D-xyloside, which disrupts proteoglycan metabolism. The markers examined included accumulation of primary mesenchyme-specific mRNA (SM 50); an aboral ectoderm-specific mRNA (Spec 1); and a gut-specific enzyme, alkaline phosphatase. Treatment with BAPN or beta-D-xyloside results in developmental arrest at the mesenchyme blastula stage. Although spicule formation is inhibited, the accumulation of SM 50 transcripts and the synthesis of most of the prominent spicule matrix proteins is similar to that of control embryos. Spec 1 mRNA, in contrast, while accumulating to a significant extent when collagen and proteoglycan metabolism is disrupted, does accumulate to a level somewhat lower than that seen in control embryos. Additionally, the postgastrula rise in gut-specific alkaline phosphatase is reversibly inhibited by BAPN and xyloside treatment. These results demonstrate a differential effect of the ECM on expression of tissue-specific molecular markers.
Mol Reprod Dev 1991 Jul
PMID:Role of the extracellular matrix in tissue-specific gene expression in the sea urchin embryo. 193 Oct 40

We have studied the structure and expression of histone H2B mRNA and genes in the parasitic protozoan Leishmania enrietti. A genomic clone containing three tandemly repeated genes has been sequenced and shown to encode three identical histone proteins and two types of closely related mRNA sequence. We have also sequenced three independent cDNA clones and demonstrated that the Leishmania H2B mRNAs are polyadenylated, similar to the basal histone mRNAs of higher eucaryotes and the histone mRNAs of yeast. In addition, the Leishmania mRNAs contain inverted repeats near the poly(A) tail which could form stem-loops similar in secondary structure, but not in sequence, to the 3' stem-loops of nonpolyadenylated replication-dependent histones of higher eucaryotes. Unlike the replication-dependent histones, the Leishmania histone H2B mRNAs do not decrease in abundance following treatment with inhibitors of DNA synthesis. The histone mRNAs are differentially expressed during the parasite life cycle and accumulate to a higher level in the extracellular promastigotes (the form which in nature lives within the gut of the insect vector) than in the intracellular amastigotes (the form that lives within the mammalian host macrophages).
Mol Cell Biol 1991 Jan
PMID:Structure and regulation of histone H2B mRNAs from Leishmania enriettii. 198 23

The utility of biodegradable and biocompatible microspheres as a vaccine delivery system for the induction of systemic and disseminated mucosal antibody responses was investigated. Intraperitoneal (ip) injection into mice of 1-10 microns microspheres, constructed of the copolymer poly(DL-lactide-coglycolide) (DL-PLG) which contained approximately 1% by weight a formalinized toxoid vaccine of staphylococcal enterotoxin B (SEB), dramatically potentiated the circulating IgG anti-toxin antibody response as compared to the free toxoid. The initiation of vaccine release was delayed in larger microspheres, and a mixture of 1-10 and 20-50 microns microspheres stimulated both a primary and an anamnestic secondary anti-toxin response following a single injection. However, neither free nor microencapsulated SEB toxoid induced a detectable mucosal IgA anti-toxin response following systemic injection. In contrast, three peroral immunizations with toxoid-microspheres stimulated circulating IgM, IgG and IgA anti-toxin antibodies and a concurrent mucosal IgA response in saliva, gut washings and lung washings. Systemic immunization with microencapsulated toxoid primed for the induction of disseminated mucosal IgA responses by subsequent oral or intratracheal (it) boosting in microspheres, while soluble toxoid was ineffective at boosting. These results indicate that biodegradable and biocompatible microspheres represent an adjuvant system with potentially widespread application in the induction of both circulating and mucosal immunity.
Mol Immunol 1991 Mar
PMID:Biodegradable microspheres as a vaccine delivery system. 201 98

The metabolism of the progestogen oral contraceptive norgestimate has been studied in vitro using human intestinal mucosa and human liver microsomes. Metabolites have been separated using radiometric high-performance liquid chromatography (HPLC) and identified by co-chromatography with authentic standards and by mass spectrometry. Histologically normal colon was obtained from 6 patients undergoing various resections and the mucosa mounted between 2 perspex (Ussing) chambers. 2 h after addition of [3H]norgestimate to the mucosal chamber, more than 95% of the radioactivity was present in that chamber. Metabolite analysis showed 38.1 +/- 11.6% (mean +/- SD; n = 8) of drug present was norgestimate, 49.2 +/- 14.5% as 17-deacetyl norgestimate and 8.1 +/- 4.5% as conjugated metabolites. Small amounts of 3-keto norgestimate, norgestrel and uncharacterized metabolites were found. Norgestimate was also metabolized by stomach tissue with 17-deacetyl norgestimate again being the main metabolite found. Microsomes were prepared from 6 human livers. Metabolism was studied over a 5 h time-course in the absence and presence of NADPH. Deacetylation to 17-deacetyl norgestimate took place in the absence of the cofactor. In the presence of NADPH, after 5 h incubation only 30.5 +/- 14.6% (mean +/- SD) of steroid present was norgestimate. The major metabolite formed was 17-deacetyl norgestimate which accounted for 39.3 +/- 20.5%. Less than 2% was present as 3-keto norgestimate but 10.0 +/- 2.3% was identified as norgestrel and 15.5 +/- 8.9% as uncharacterized metabolites. We also examined the microsomal breakdown of [3H]17-deacetyl norgestimate. This was NADPH and oxygen dependent. Norgestrel and other metabolites were formed. This study has demonstrated that norgestimate is rapidly deacetylated by both gut wall and liver. The deacetylated metabolite can then be further metabolized.
J Steroid Biochem Mol Biol 1991 Apr
PMID:Metabolism of norgestimate by human gastrointestinal mucosa and liver microsomes in vitro. 203 63

Expression of the mammalian prepro-gastrin-releasing peptide (preproGRP) gene has been shown to be restricted to neural and neuroendocrine cell types. In this paper, the structure and nucleotide sequence of the rat preproGRP gene coding regions and promoter is described and analyzed. The gene is divided into 3 exons, encoding a signal sequence, the 29 amino acid rat GRP, and a 92 amino acid extension peptide. While the overall prohormone structure is similar to that predicted from the sequence of the human gene, differences in transcription are apparent. Several forms of the rat preproGRP mRNA are found in brain: a 1.1 kb form which initiates in both brain and gut primarily from a TATAA-directed promoter, and less abundant forms of about 1.5 kb, whose initiation sites are heterogeneous, located 300-400 base pairs upstream of the 1.1 kb initiation site, and found only in spinal cord and a subset of brain nuclei expressing preproGRP mRNA. Comparison of the human and rat promoter region sequences identifies regions of high similarity upstream from both the 1.1 kb and 1.5 kb mRNA initiation sites, which may be important in the cell type-specific regulation of the preproGRP gene.
Brain Res Mol Brain Res 1990 Apr
PMID:Structural characterization of a brain-specific promoter region directing transcription of the rat prepro-gastrin-releasing peptide gene. 215 83

Leishmania exist as extracellular promastigotes which multiply in the gut of the sandfly insect vector and as intracellular amastigotes which divide in the phagolysosome of mononuclear phagocytic cells of the mammalian host. Promastigotes express a major surface glycoprotein of 63 kDa, referred to as GP63. The expression of GP63 in both Leishmania life stages was studied using rabbit antibodies against native GP63 as well as rabbit antibodies against recombinant GP63 that was synthesized in an Escherichia coli expression system. Immunofluorescence staining detected GP63 in intracellular amastigotes contained within a macrophage cell line and within freshly isolated lesion amastigotes. Western blot analysis using anti-recombinant GP63 antibodies also demonstrated that amastigotes synthesize GP63 which may undergo differential post-translational processing as compared to promastigote GP63.
Mol Biochem Parasitol 1990 Jan 01
PMID:The major surface glycoprotein (GP63) is present in both life stages of Leishmania. 218 3


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