Identification of spermatogenic cell plasma membrane glycoproteins by two-dimensional electrophoresis and lectin blotting

1984 ◽  
Vol 65 (1) ◽  
pp. 233-248
Author(s):  
C.F. Millette ◽  
B.K. Scott

Plasma membrane glycoproteins present in purified mouse spermatogenic cells have been identified by two-dimensional polyacrylamide gel electrophoresis and lectin blotting techniques. Four membrane glycoproteins labelled with Bandeiraea simplicifolia lectin (I) have been detected, ranging in Mr from 55 000 to 76 000 and in pI from 6.0 to 6.3. Only one of these proteins, p76/6.3, is synthesized by short-term in vitro cultures of spermatogenic cells, as determined by the incorporation of [35S]methionine. Approximately 20 surface glycoproteins labelled with concanavalin A have been identified, ranging in Mr from 50 000 to 151 000 and in pI from 5.7 to 7.0. None of the components detected with B. simplicifolia lectin (I) are labelled significantly with concanavalin A. A major concanavalin A-binding protein in the membranes of both pachytene spermatocytes and round spermatids is p151/6.0. This glycoprotein has been previously shown to be exposed on the outer surface of spermatogenic cell membranes and may represent a mediator of germ cell-Sertoli cell interactions. Furthermore, two constituents identified in the present study represent stage-specific markers. Component p73/5.7 is detected with concanavalin A only in the membranes of pachytene spermatocytes. Conversely, p84/6.3 is found only in round spermatid membranes. These results, then have: (a) provided a map of membrane glycoproteins in developing mouse male germ cells; (b) identified p151/6.0 as a membrane constituent of possible functional significance; and (c) identified the first reported glycoprotein surface differentiation markers for mouse spermatogenesis.

1987 ◽  
Vol 245 (1) ◽  
pp. 75-83 ◽  
Author(s):  
G Gorini ◽  
G A Medgyesi ◽  
M Garavini ◽  
K J Dorrington ◽  
J Down

Two membrane glycoproteins that bound immune complexes and inhibited Fc-receptor- (FcR-)mediated functions in vitro were purified from human FcR+ chronic-lymphocytic-leukaemia cells. A multi-step purification was developed, consisting essentially in: (i) Tween 40 extraction of crude cell membranes; (ii) solubilization of membrane fragments by Renex-30; (iii) isolation of glycoproteins by affinity chromatography on Lens culinaris haemagglutinin-Sepharose; (iv) papain treatment of the eluted glycoproteins followed by gel-filtration chromatography; (v) purification by polyacrylamide-gel electrophoresis of two molecular species from the protein-size fraction enriched for immune-complex-binding activity. The two electrophoretically isolated components displayed apparent molecular masses of 70 and 45 kDa by SDS/polyacrylamide-gel electrophoresis and restricted charge heterogeneity by two-dimensional analysis. Two-dimensional peptide mapping revealed the presence of many peptides in common between the two proteins and the absence of a number of peptides in the 45 kDa component. These two polypeptides were used as immunogens to produce polyclonal antibodies that cross-reacted with both proteins and specifically inhibited FcR-mediated reactions in vitro. Furthermore, FcR-related components from detergent-extracted lysates of the human K562 and U937 cell lines or human placental membranes were revealed by the putative anti-FcR antibodies adsorbed on Protein A-Sepharose.


1982 ◽  
Vol 139 (2) ◽  
pp. 472-475 ◽  
Author(s):  
J GROOTEGOED ◽  
N JUTTE ◽  
F ROMMERTS ◽  
H VANDERMOLEN ◽  
S OHNO

1986 ◽  
Vol 6 (12) ◽  
pp. 4478-4485 ◽  
Author(s):  
A T Garber ◽  
J Segall

The SPS4 gene of Saccharomyces cerevisiae, a sporulation-specific gene identified previously in a differential hybridization screen of a genomic yeast DNA library, has been characterized further. The protein encoded by this gene was inferred from its nucleotide sequence to be 38,600 daltons with an isoelectric pH of 8.2. Consistent with this, two-dimensional polyacrylamide gel electrophoresis of the in vitro translation products of RNA purified by hybridization with the cloned SPS4 DNA indicated that the SPS4 gene product is a 39-kilodalton, basic protein. This protein was found to be identical in size and charge to a major, sporulation-specific protein identified in a two-dimensional polyacrylamide gel electrophoretic comparison of the in vitro translation products of total RNA from sporulating MATa/MAT alpha cells and asporogenous MAT alpha/MAT alpha cells. A MATa/MAT alpha strain homozygous for a partial deletion of the SPS4 gene appeared, however, to be unaffected in its ability to form viable ascospores.


1975 ◽  
Author(s):  
J. N. George ◽  
P. C. Lewis ◽  
D. A. Sears

The initial events of hemostasis and thrombosis involve platelet contact interactions and may be mediated by surface glycoproteins. Human and rabbit platelets were labeled with 125I-diazotized diiodosulfanilic acid (I), which reacts covalently with proteins, and proteins were separated by SDS-polyacrylamide gel electrophoresis. Only exposed membrane proteins were labeled because: 1) protein specific activity of membranes was 4-7 times that of whole platelets, 2) different proteins were labeled when I was reacted with isolated membranes, and 3) trypsin-hydrolysis of labeled intact platelets altered the radioactive peaks. Like Phillips (Biochem. 11, 4582, 72) and Nachman et al. (JBC 248, 2928, 73) we found that lactoperoxidase iodinated the 93,000 dalton glycoprotein (GP) of human platelets. In contrast, I labeled both the 93,000 and 118,000 dalton membrane GP of human platelets, and all 3 membrane GP of rabbit platelets.Rabbit platelets labeled simultaneously with I and 51Cr had identical density and therefore age distribution of the 2 labels. After infusion into rabbits, initial recovery of I was 23% of the Cr recovery. After 3 hrs, I disappearance was exponential and more rapid (T/2 = 17 hrs) than the linear Cr disappearance (T/2 = 30 hrs, p < .01). This was due to in vivo removal of I from circulating platelets since 1 did not elute more rapidly from platelets harvested after 3 hrs circulation and incubated in plasma at 37° (T/2 of I elution = 43 hrs, Cr = 33 hrs). Platelets harvested after 14-20 hrs circulation had the same distribution of I on the membrane GP as before circulation. We postulate that this symmetrical label loss indicates uniform loss of membrane GP, suggesting that platelets lose pieces of their plasma membrane during circulation. This could occur during contact interaction in the process of hemostasis.


1988 ◽  
Vol 36 (2) ◽  
pp. 167-178 ◽  
Author(s):  
K Wasano ◽  
K C Kim ◽  
R M Niles ◽  
J S Brody

We describe here a system for culturing epithelial cells isolated from hamster trachea, which results in a highly enriched population of mucus-secreting cells. The culture system has enabled us to study the process of secretory cell differentiation in vitro. We found that epithelial secretory cells, in vivo and after 5 days in vitro, selectively bind the lectin Helix pomatia agglutinin (HPA) to apical and, to a lesser extent, basolateral surfaces as well as to mucin granules and intracellular secretory organelles. SDS-PAGE gels of detergent extracts of secretory cells cultured for 5 days reveal three HPA-binding glycoproteins with MW of 120 KD, 220 KD, and greater than 400 KD. The high-MW glycoprotein appears identical to mucin, since it is found in secretions from intact trachea and in spent media from 5-day cultures. It does not appear in spent media from 3-day cultures when cells contain few mucous granules and secrete little mucin. The 220 KD HPA-binding glycoprotein is also present in 5-day but not in 3-day cultures. In contrast, the 120 KD glycoprotein is present at both times. HPA-gp120 is a hydrophobic integral membrane protein, whereas HPA-gp220 and mucin are hydrophilic and are membrane associated. These studies define three membrane glycoproteins, one of which is specific for the tracheal epithelial secretory cell regardless of its mucous content, whereas the other two glycoproteins correlate with mucin secretion. They also demonstrate that, in the fully differentiated state, mucin is bound in a non-covalent fashion to the apical plasma membrane of the tracheal epithelial secretory cell.


Blood ◽  
1986 ◽  
Vol 67 (3) ◽  
pp. 682-688 ◽  
Author(s):  
RB Jenkins ◽  
WL Nichols ◽  
KG Mann ◽  
LA Jr Solberg

Abstract Human megakaryocytes have been shown by immunofluorescent techniques to express platelet glycoprotein IIb/IIIa antigen. We report evidence that megakaryocytes derived from human committed megakaryocytic progenitor cells in vitro (CFU-M) synthesize glycoproteins IIb and IIIa. Nonadherent light-density human bone marrow cells were cultured in human plasma and methylcellulose using conditions that promote large megakaryocytic colonies. On day 13 the megakaryocytic colonies were picked, pooled, and pulsed with 35S-methionine in methionine-free media. Populations of approximately 100,000 cells with greater than or equal to 95% viability and containing 70% to 90% megakaryocytes were obtained reliably for study. After the radioactive pulse, the cell suspension was solubilized with nonionic detergent. To reduce nonspecific binding of 35S-labeled proteins to agarose, the lysate was chromatographed sequentially on glycine-quenched Affi-gel and antihuman factor X-Sepharose. The unbound material from these resins was then chromatographed on an antiglycoprotein IIb/IIIa monoclonal antibody resin (HP1–1D-Sepharose) or on a control monoclonal antibody resin. Bound fractions were eluted and analyzed by polyacrylamide gel electrophoresis and autoradiography. Autoradiograms of diethylamine eluates from HP1–1D-Sepharose revealed two labeled proteins with electrophoretic mobilities identical with those of human platelet membrane glycoproteins IIb and IIIa, isolated using similar conditions. Autoradiograms of material synthesized by control macrophages from the same donors revealed no significant labeling of proteins in the glycoprotein IIb/IIIa molecular weight range, nor were such proteins bound by HP1–1D-Sepharose. Our observations show that protein synthesis by CFU-M-derived human megakaryocytes can be readily studied using a small amount of bone marrow aspirate as starting material. This approach will allow the study of protein synthesis by megakaryocytes from normal subjects or from subjects with clinical disorders, and it will circumvent the need to obtain large amounts of bone marrow to prepare enriched populations of megakaryocytes.


1999 ◽  
Vol 11 (6) ◽  
pp. 379 ◽  
Author(s):  
Madhabi Barua ◽  
Anil K. Ghosh ◽  
Gopal C. Majumder

A phosphoprotein phosphatase (PPase M-I) that dephosphorylates serine and threonine residues of histones was isolated from the goat cauda-epididymal sperm plasma membrane and partially characterized. The PPase was solubilized from the sperm membrane by treating it with 0.1 N NaOH at pH 11.4 and the solubilized enzyme was partially purified by concanavalin A-sepharose affinity chromatography and high-performance liquid chromatography (HPLC), revealing it to be a 520-kDa protein. The PPase gave a single protein band in native polyacrylamide gel electrophoresis (PAGE), but in the presence of SDS it resolved into multiple proteins (35–170 kDa) showing that the isolated enzyme contained a few contaminating proteins. The enzyme is a glycoprotein because it binds with high affinity to concanavalin A. It was maximally active at pH 8.0 and its activity was not dependent on bivalent metal ions. The enzyme is a specific phosphatase as it displayed higher affinity for dephosphorylation of large molecular weight phosphate esters. The PPase showed broad substrate specificity for the dephosphorylation of a variety of proteins. The membrane-associated PPase was strongly (70–80%) inhibited by detergents (0.5%) such as Nonidet P-40, Lubrol PX, Triton X-100 and Tween-20. Pyrophosphate (5 mM) and orthovanadate (400 M) had no significant effect on the activity of the isolated PPase whereas polyamines such as spermine (10 mM) nd spermidine (10 mM) slightly inhibited (20%) the enzymatic activity. Inorganic phosphate (10 mM) and NaF (10 mM), the well-known inhibitors of the cytosolic PPases, had no appreciable effect on the activity of PPase M-I, indicating that the membrane-bound PPase is distinct from the cytosolic PPases. The enzyme was radiolabelled when the intact spermatozoa were subjected to lactoperoxidase-mediated radioiodination reaction. The results show that the PPase M-I is an ecto-enzyme that may play an important role in sperm physiology by causing the dephosphorylation of the sperm outer surface phosphoproteins.


1994 ◽  
Vol 107 (10) ◽  
pp. 2887-2898
Author(s):  
M. Morse-Gaudio ◽  
M.S. Risley

The relative content of topoisomerase II (topo II) and the induction of topo-II-mediated DNA damage and cellular abnormalities have been characterized in developing spermatogenic cells of Xenopus laevis to gain an insight into the role of topo II during spermatogenesis. Decatenation assays identified topo II activity in nuclear extracts from spermatocytes and pre-elongate spermatids, but not in extracts from elongate spermatids or sperm. Extracts from early-mid spermatids contained 14% (per cell) of the decatenation activity found in spermatocyte extracts. Immunoblots of SDS extracts from whole cells and nuclei from both spermatocytes and pre-elongate spermatids, but not elongate spermatids or sperm, resolved a 180 kDa polypeptide that reacts with polyclonal antisera to Xenopus oocyte topo II, an antipeptide antibody (FHD29) to human topo II alpha and beta, and an antipeptide antibody to human topo II alpha, suggesting homology between Xenopus spermatogenic cell topo II and mammalian topo II alpha. Immunofluorescence microscopy of topo II in testis cryosections revealed the presence of topo II in nuclei of all spermatogenic stages, but not in sperm. The relative levels of topo II estimated from fluorescence intensity were highest in spermatogonia and spermatocytes, then early-mid spermatids, followed by elongate spermatids and somatic cells. Incubation of isolated spermatogenic cells with teniposide (VM-26), a topo II-targetted drug, resulted in a dose-dependent induction of DNA breaks in all spermatocytes and spermatid stages to nuclear elongation stages, as analyzed by alkaline single cell gel electrophoresis. Addition of 0.5-50 microM VM-26 to spermatogenic cell cultures for 27 hours resulted in stage-dependent abnormalities. Mid-late spermatid stages were relatively resistant to VM-26-induced damage. In contrast, meiotic division stages were arrested and spermatogonia B were killed by VM-26, and VM-26 induced abnormal chromosome condensation in pachytene spermatocytes. The results of these studies show that cellular levels of topo II are stage-dependent during spermatogenesis, that most spermatogenic stages are sensitive to topo II-mediated DNA damage, and that spermatogonia B, meiotic divisions and pachytene spermatocytes are particularly sensitive to induction of morphological abnormalities and cell death during acute exposure to topo II-targetted drugs.


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