Interphase phosphorylation of the Drosophila nuclear lamin: site-mapping using a monoclonal antibody

1995 ◽  
Vol 108 (9) ◽  
pp. 3137-3144 ◽  
Author(s):  
N. Stuurman ◽  
N. Maus ◽  
P.A. Fisher

The Drosophila nuclear lamin is highly phosphorylated during interphase. Two interphase isoforms, differing in degree of phosphorylation, can be distinguished by one-dimensional SDS-polyacrylamide gel electrophoresis. One migrates with an apparent mass of 74 kDa (lamin Dm1); the other is more highly phosphorylated and migrates as a 76 kDa protein (lamin Dm2). We generated a monoclonal antibody, ADL84 which binds to lamin Dm1 but not lamin Dm2. Binding of ADL84 to lamin Dm2 was restored by phosphatase treatment of immunoblots containing lamins. Immunoprecipitation with ADL84 demonstrated that purified Drosophila nuclear lamins Dm1 and Dm2 are present as a random mixture of homo- and heterodimers. Indirect immunofluorescence experiments suggest that lamin Dm1 is present in all Drosophila cell types. The epitope for ADL84 was mapped by analyzing binding to bacterially expressed lamin deletion mutants and subsequently by screening for point mutants (randomly generated by polymerase chain reaction) which were not recognized by ADL84. The ADL84-epitope encompasses amino acids R22PPSAGP (arginine 22-proline 28). Peptide competition experiments demonstrated directly that phosphorylation of serine 25 impedes lamin binding by ADL84. This suggests that serine 25 is the lamin Dm2-specific phosphorylation site.

2021 ◽  
Vol 118 (25) ◽  
pp. e2107770118
Author(s):  
Natalie Y. Chen ◽  
Paul H. Kim ◽  
Yiping Tu ◽  
Ye Yang ◽  
Patrick J. Heizer ◽  
...  

Defects or deficiencies in nuclear lamins cause pathology in many cell types, and recent studies have implicated nuclear membrane (NM) ruptures as a cause of cell toxicity. We previously observed NM ruptures and progressive cell death in the developing brain of lamin B1–deficient mouse embryos. We also observed frequent NM ruptures and DNA damage in nuclear lamin–deficient fibroblasts. Factors modulating susceptibility to NM ruptures remain unclear, but we noted low levels of LAP2β, a chromatin-binding inner NM protein, in fibroblasts with NM ruptures. Here, we explored the apparent link between LAP2β and NM ruptures in nuclear lamin–deficient neurons and fibroblasts, and we tested whether manipulating LAP2β expression levels would alter NM rupture frequency. In cortical plate neurons of lamin B1–deficient embryos, we observed a strong correlation between low LAP2β levels and NM ruptures. We also found low LAP2β levels and frequent NM ruptures in neurons of cultured Lmnb1−/− neurospheres. Reducing LAP2β expression in Lmnb1−/− neurons with an siRNA markedly increased the NM rupture frequency (without affecting NM rupture duration), whereas increased LAP2β expression eliminated NM ruptures and reduced DNA damage. Consistent findings were observed in nuclear lamin–deficient fibroblasts. Reduced LAP2β expression increased NM ruptures, whereas increased LAP2β expression virtually abolished NM ruptures. Increased LAP2β expression nearly abolished NM ruptures in cells subjected to mechanical stress (an intervention that increases NM ruptures). Our studies showed that increasing LAP2β expression bolsters NM integrity in nuclear lamin–deficient cells and markedly reduces NM rupture frequency.


1987 ◽  
Vol 244 (3) ◽  
pp. 625-631 ◽  
Author(s):  
S C Smith ◽  
W J McAdam ◽  
B E Kemp ◽  
F J Morgan ◽  
R G Cotton

Monoclonal antibody PH7 has specificity for the phosphorylated form of the human liver phenylalanine hydroxylase and negligible reactivity towards the dephosphorylated form of the native enzyme by enzyme-linked immunoassay. PH7 binds specifically to the phosphorylated form of the liver enzyme after SDS/polyacrylamide-gel electrophoresis and transfer to nitrocellulose. Competitive blocking assays have been applied in conjunction with reversed-phase h.p.l.c. of purified tryptic fragments of human liver phenylalanine hydroxylase to localize the epitope. The major immunoreactive tryptic peptide cross-reacting with PH7 had an amino acid analysis corresponding to the first 41 amino acids of the human liver phenylalanine hydroxylase sequence and included the serine residue that is thought to be the phosphorylation site. The monoclonal antibody recognized the phosphorylated form of the synthetic decapeptide corresponding to the local phosphorylation-site sequence Gly-Leu-Gly-Arg-Lys-Leu-Ser(P)-Asp-Phe-Gly, but not the dephosphodecapeptide. Thermolysin digestion of the peptide demonstrated the monoclonal antibody bound to the pentapeptide Leu-Ser(P)-Asp-Phe-Gly. Monoclonal antibody PH7 recognized the phosphodecapeptide at concentrations 10(3)-fold higher than with phenylalanine hydroxylase, compared with 10(4)-10(7)-fold higher for other phosphopeptides and phosphoproteins. The results demonstrate that monoclonal antibody PH7 has specificity for the phosphorylated form of phenylalanine hydroxylase at the phosphorylation site.


1994 ◽  
Vol 72 (05) ◽  
pp. 762-769 ◽  
Author(s):  
Toshiro Takafuta ◽  
Kingo Fujirmura ◽  
Hironori Kawano ◽  
Masaaki Noda ◽  
Tetsuro Fujimoto ◽  
...  

SummaryGlycoprotein V (GPV) is a platelet membrane protein with a molecular weight of 82 kD, and one of the leucine rich glycoproteins (LRG). By reverse transcription-polymerase chain reaction (RT-PCR), GPV cDNA was amplified from mRNA of platelets and megakaryocytic cell lines. However, since there are few reports indicating whether GPV protein is expressed in megakaryocytes as a lineage and maturation specific protein, we studied the GPV expression at the protein level by using a novel monoclonal antibody (1D9) recognizing GPV. Flow cytometric and immunohistochemical analysis indicated that GPV was detected on the surface and in the cytoplasm of only the megakaryocytes in bone marrow aspirates. In a megakaryocytic cell line UT-7, GPV antigen increased after treatment with phorbol-12-myri-state-13-acetate (PMA). These data indicate that only megakaryocytes specifically express the GPV protein among hematopoietic cells and that the expression of GPV increases with differentiation of the megakaryocyte as GPIb-IX complex.


1981 ◽  
Vol 197 (3) ◽  
pp. 629-636 ◽  
Author(s):  
J L McKenzie ◽  
A K Allen ◽  
J W Fabre

Human and canine brain Thy-1 antigens were solubilized in deoxycholate and antigen activity was followed both by conventional absorbed anti-brain xenosera of proven specificity and by mouse monoclonal antibodies to canine and human Thy-1. It is shown that greater than 80% of Thy-1 activity in the dog and man binds to lentil lectin, that the mobility on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis of canine and human Thy-1 is identical with that of rat Thy-1 and that the Stokes radius in deoxycholate of canine and human brain Thy-1 is 3.0 nm and 3.25 nm respectively. Both lentil lectin affinity chromatography followed by gel-filtration chromatography on the one hand and monoclonal antibody affinity chromatography on the other gave high degrees of purification of the brain Thy-1 molecule in the dog and man, resulting in single bands staining for both protein and carbohydrate on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis (except for a slight contaminant of higher molecular weight staining for protein but not carbohydrate with human Thy-1 purified by lentil lectin and gel-filtration chromatography). Analysis of canine and human brain Thy-1 purified by monoclonal antibody affinity chromatography with additional gel filtration through Sephadex G-200 showed that these molecules had respectively 38% and 36% carbohydrate. The amino acid and carbohydrate compositions were similar to those previously reported for Thy-1 of the rat and mouse, the main point of interest being the presence in canine and human brain Thy-1 of N-acetylgalactosamine, which has been reported in rat and mouse brain Thy-1 but not in Thy-1 from other tissues.


1979 ◽  
Vol 82 (1) ◽  
pp. 86-92 ◽  
Author(s):  
SJ Horovitch ◽  
RV Storti ◽  
A Rich ◽  
ML Pardue

The tissue and developmental specificities of the three Drosophila isoactins, originally identified in primary myogenic cultures and in the permanent Schneider L-2 cell line, have been investigated. Of these three isoactins (I, II, and III), actins I and II are stable and actin III is unstable. Two-dimensional polyacrylamide gel electrophoretic analyses of total cellular extracts after 1-h [(35)S]methionine pulses were performed on a large variety of embryonic, larval, and adult muscle and nonmuscle tissues. The results suggest that isoactins II and III are generalized cellular actins found in all drosophila cell types. Actin I, on the other hand, is muscle-associated and is found exclusively in supercontractile muscle (such as larval body wall and larval and adult viscera) including primary myogenic cell cultures. Although actin I synthesis is not detectable during very early embryogenesis, it is detectable by 25 h and actin I is a major stable actin in all larval muscle tissues. Actin I is synthesized in reduced amounts relative to the other actins in late third instar larvae but is again a major product of actin synthesis in the adult abdomen. A stable actin species with the same pI as actin III has been identified in the adult thorax and appears to be unique to flight muscle tissue. This new stable form of thoracic actin may be the result of a stabilization of the actin III found in other tissues or may be an entirely separate gene product.


1999 ◽  
Vol 41 (5) ◽  
pp. 291-295 ◽  
Author(s):  
Abdel-Hamid Zaki ABDEL-HAMID ◽  
Jeanne Blanco de MOLFETTA ◽  
Vania FERNANDEZ ◽  
Vanderlei RODRIGUES

Susceptibility of snails to infection by certain trematodes and their suitability as hosts for continued development has been a bewildering problem in host-parasite relationships. The present work emphasizes our interest in snail genetics to determine what genes or gene products are specifically responsible for susceptibility of snails to infection. High molecular weight DNA was extracted from both susceptible and non-susceptible snails within the same species Biomphalaria tenagophila. RAPD was undertaken to distinguish between the two types of snails. Random primers (10 mers) were used to amplify the extracted DNA by the polymerase chain reaction (PCR) followed by polyacrylamide gel electrophoresis (PAGE) and silver staining. The results suggest that RAPD represents an efficient means of genome comparison, since many molecular markers were detected as genetic variations between susceptible and non-susceptible snails.


Blood ◽  
1986 ◽  
Vol 68 (3) ◽  
pp. 737-742
Author(s):  
BR Tomasini ◽  
DF Mosher

Vitronectin (serum spreading factor), a major serum cell adhesion molecule, was compared with S-protein, the inhibitor of the C5–9 membrane attack complex. Data from the literature indicate that S- protein and vitronectin are alpha globulins with the same aminoterminal residues, amino acid compositions, and concentrations in normal plasma (150 to 250 micrograms/mL). Both proteins have been reported to interact with the thrombin-antithrombin complex. The cDNA sequences of vitronectin and S-protein were recently determined and found to be almost identical. In the present studies, rabbit-anti-S-protein and a monoclonal antibody to vitronectin both recognized 65,000- and 75,000- molecular weight (mol wt) polypeptides when plasma or serum proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and transferred to nitrocellulose paper. The 65,000 and 75,000-mol wt polypeptides bound more avidly from serum than plasma to monoclonal anti-vitronectin or heparin coupled to agarose. The presence or absence of the polypeptides constituted a major difference between the heparin-binding proteins of serum and plasma. When complement- activated serum and unactivated serum were separated by gel filtration, vitronectin coeluted with C9 in high-mol-wt fractions of activated serum but not unactivated serum. Purified S-protein was recognized by the monoclonal antibody to vitronectin and promoted spreading of human skin fibroblasts. Both vitronectin and S-protein were degraded by thrombin. On the basis of immunological and functional, as well as biochemical, properties, therefore, S-protein and vitronectin are the same.


2016 ◽  
Vol 20 (1) ◽  
pp. 54 ◽  
Author(s):  
K. Kristamtini ◽  
T. Taryono ◽  
Panjisakti Basunanda ◽  
Rudi Hari Murti

Microsatellite markers or simple sequences repeats are DNA - based molecular techniques that areused to see the different among accessions and inbred lines. There are three methods to analysis the results ofthe polymerase chain reaction of microsatellite markers namely polyacrylamide gel electrophoresis (PAGE),capillary electroforesis, and Metaphor Agarose Gel Electroforesis (MAGE), and the Use of MAGE assessedmore easily and economically the polymorphic pattern of DNA markers. This study aimed to obtain fast,effective and efficient in term of easy and cheap technique to identify microsatellite markers of some blackrice cultivars and F2 populations from crosses between black with white rice. The results showed that MAGEsuccessfully separated clearly SSRs alleles with different sizes of less than 25 bp .


1991 ◽  
Vol 58 (3) ◽  
pp. 193-201 ◽  
Author(s):  
Franco Rollo ◽  
Franco Maria Venanzi ◽  
Augusto Amici

SummaryNucleic acids fractions were isolated from pre-Columbian maize seeds and characterized using different approaches such as polyacrylamide gel electrophoresis, anti-DNA antibody binding, HPLC fractionation, molecular hybridization with cloned genes, and DNA amplification by the polymerase chain reaction. The nucleic acids were found to be very depolymerized (≤140 base pairs in length) and composed mainly of ribosomal RNA. Despite the very low amount and degree of polymerization of seed DNA, specific maize nuclear Mul, Mu4, Mu8 and, possibly, Mu5 element components could be detected, thanks to the use of amplification systems as short as 90 bp. The results suggest that evaluation of the relative proportions of Mu-type element components and, possibly, other maize genomic components in single mummified kernels, may offer a new key to the study of ancient maize populations.


2002 ◽  
Vol 115 (5) ◽  
pp. 923-929 ◽  
Author(s):  
Yosef Gruenbaum ◽  
Kenneth K. Lee ◽  
Jun Liu ◽  
Merav Cohen ◽  
Katherine L. Wilson

Emerin belongs to the LEM-domain family of nuclear membrane proteins, which are conserved in metazoans from C. elegans to humans. Loss of emerin in humans causes the X-linked form of Emery-Dreifuss muscular dystrophy(EDMD), but the disease mechanism is not understood. We have begun to address the function of emerin in C. elegans, a genetically tractable nematode. The emerin gene (emr-1) is conserved in C. elegans. We detect Ce-emerin protein in the nuclear envelopes of all cell types except sperm, and find that Ce-emerin co-immunoprecipitates with Ce-lamin from embryo lysates. We show for the first time in any organism that nuclear lamins are essential for the nuclear envelope localization of emerin during early development. We further show that four other types of nuclear envelope proteins, including fellow LEM-domain protein Ce-MAN1, as well as Ce-lamin, UNC-84 and nucleoporins do not depend on Ce-emerin for their localization. This result suggests that emerin is not essential to organize or localize the only lamin (B-type) expressed in C. elegans. We also analyzed the RNAi phenotype resulting from the loss of emerin function in C. elegans under laboratory growth conditions, and found no detectable phenotype throughout development. We propose that C. elegans is an appropriate system in which to study the molecular mechanisms of emerin function in vivo.


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