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T Persson

Publications and source records attributed to T Persson.

At least 73 records · Page 4Linked to original sources
PubMed1982

A 90 000-dalton actin-binding protein from platelets. Comparison with villin and plasma brevin.

Affinity chromatography of Ca2+-containing extracts of platelets on DNAase I-Sepharose, using Ca2+-free buffer as eluant, selects a 1:1 complex of a 90 000-dalton protein with actin. The complex shows little interaction with either DNAase or actin unless Ca2+ is present. In the presence of Ca2+, the complex nucleates polymerization of actin, reduces the viscosity attained, and delays filament formation from profilactin with characteristics closely resembling those shown by chicken villin. Proteolysis of the native proteins indicates structural similarity between the platelet protein and villin or villin core; limited proteolytic digestion in the presence of SDS distinguishes the platelet protein from villin but not from the functionally related plasma protein, brevin. The platelet protein is not accessible to enzyme-mediated iodination of surface components on intact cells. The term 'platelet brevin' is proposed for the protein.

Actins↗
PubMed1981

Characterization of platelet extracts before and after stimulation with respect to the possible role of profilactin as microfilament precursor.

The amount of profilactin in platelet extracts made in the absence of free Ca++ ions decreases and the amount of free profilin increases as a consequence of thrombin stimulation. This agrees with the proposed role of profilactin as a microfilament precursor in nonmuscle cells. Filamentous actin in extracts of unstimulated platelets appears partly in large aggregates that contain actin binding protein (ABP) and relatively few other proteins. After stimulation, the amounts of actin and ABP in the aggregates are increased and myosin is also included together with a few additional proteins. When the cells are lysed in the presence of Ca++, aggregation is drastically reduced. The data indicate that filamentous actin depolymerizes rapidly and recombines with available profilin, and that a Ca-specific interaction also occurs between actin and a new protein with molecular weight about 90,000.

Actins↗
PubMed1979

Reorganization of actin in platelets stimulated by thrombin as measured by the DNase I inhibition assay.

The effect of thrombin stimulation on actin organization in human platelets has been analyzed by using the DNase I inhibition assay, which is selective for unpolymerized and filamentous actin. The results provide biochemical evidence for the suggestion that stimulation leads to rapid polymerization of actin. The measurements also reveal changes in the polymerization state of actin occurring after cell lysis. These changes are influenced by the concentration of free calcium in the extracts.

Actins↗
PubMed1978

Selective assay of monomeric and filamentous actin in cell extracts, using inhibition of deoxyribonuclease I.

A simple and selective assay for monomeric and filamentous actin is presented, based on the inhibition of DNAase I by actin. In mixtures of monomeric and filamentous actin, only the monomeric form is measured as DNAase inhibitor. The total amount of actin in a sample can be determined after depolymerization of F actin with guanidine hydrochloride. The assay is rapid enough to detect changes in the polymerization state of actin in vitro over time intervals as short as 3 min. Data characterizing unpolymerized and filamentous actin pools in extracts of human platelets, lymphocytes and HeLa cells are presented.

Actins↗
PubMed1978

Factors predicing survival after portacaval shunt: a multiple linear regression analysis.

The predictive value of 15 pre- and peroperative parameters upon survival after portacaval shunt was analyzed in a retrospective investigation of 134 elective operations. A multiple linear regression model was used. Survival was measured at three different points of time: one month, one year and five years after the operation. Survival at one month was influenced by the parameters bilirubin/s and ascites only. Survival at one year was influenced by albumin/s, sex, bilirubin/s, BSP, heart disease history and ascites Survival at five years was influenced by albumin/s, alkaline phosphatase/s, history of alcohol abuse, and globulin/s. These findings indicate that prediction of survival after portacaval shunt is an intricate process and that considerable improvement of the child criteria is possible.

Female↗
PubMed1978

Distribution of CAP and methylated nucleotides between the RNase sensitive and resistant fractions of mRNA in messenger ribonucleoprotein particles.

When polyribosomal mRNP is exposed to ribonucleases most but not all of the mRNA is converted to acid soluble products. If mRNP is prepared under isotonic conditions there are two types of ribonuclease resistant core fractions, one which contains the poly(A) part of the mRNA and a second which contains mRNA fragments, 30-40 nucleotides in length. Like poly(A) these fragments appear to be protein associated in the mRNP complex. Non-poly(A) fragments in mRNP prepared from adenovirus-infected cells harvested in the late phase of infection contained only 3% of CAP structures and 12% of internally located methylated nucleotides. This indicates that no CAP structures but one out of the seven internally located methylated nucleotides found in the mRNA are situated in protein associated regions.

Adenoviridae↗
PubMed1977

Characterization of mRNA-protein complexes from mammalian cells.

In a previous report we described the use of oligo(dT)-cellulose for the isolation of mRNA-protein complexes from EDTA-dissociated polysomes extracted from normally growing or adenovirus infected KB-cells (I). Experiments presented here provide evidence that proteins involved in these complexes bind specifically to mRNA since: a) the proteins and mRNA cosediment through sucrose gradients, b) they adsorb and elute from oligo(dT)-cellulose together, and c) analysis of the products from ribonuclease digestion experiments show that the poly (A) end and a separate small fraction of the mRNA are resistant to the enzymes and attached to protein.

Adenoviridae↗
PubMed1977

Effect of homopolyribonucleotides on messenger ribonucleoprotein particles.

A discrete set of polypeptides copurify with and appear to be specifically attached to mRNA from polysomes of eukaryotic cells. This report describes the effect of homopolyribonucleotides on mRNA-protein complexes separated from ribosome subunits by oligo(dT)-cellulose chromatography. It is shown that poly (U) and poly (A) can release mRNA-protein complexes adsorbed to oligo(dT)-cellulose, whereas poly (C) and poly(I) are much less effective in this process. Analysis of polyribonucleotide released material showed that poly(U) effectively dissociated the mRNA-protein complexes while poly(A) caused no or only partial derangement of these particles. The specificities seen in the polyribonucleotide effects in turn suggest a high degree of specificity in the interaction between the proteins and mRNA.

Adenoviridae↗
PubMed1975

Identification of the in vitro translation products of adenovirus mRNA by immunoprecipitation.

Adenovirus type 2 mRNA was translated in S30 extracts from Ehrlich ascites and wheat embryo cells. The in vitro products were identified by sodium dodecyl sulfate-gel electrophoresis after immunoprecipitation with specific antisera in the presence of urea. Seven virion polypeptides could be identified by immunoprecipitation. Three of these appear to be precursors to polypeptides of the virion. mRNA isolated late in adenovirus infection was separated into three size classes by zonal sedimentation. Material sedimenting at 26S was translated into polypeptides corresponding to the largest virion polypeptides II to IV, a 22S fraction corresponding to polypeptide V, and smaller polypeptides and a 15S fraction corresponding to polypeptide IX. A significant amount of polypeptide IX was also synthesized by the 26S and 22S RNA.

Adenoviridae↗
PubMed1972

Isolation and characterization of adenovirus messenger ribonucleic acid in productive infection.

Messenger ribonucleic acid (mRNA) from cells productively infected with adenovirus type 2 was isolated by affinity chromatography on polyuridylic acid [poly (U)] bound to Sepharose. At least 90% of the polyadenylic acid [poly (A)]-containing polysomal mRNA was retained by the poly (U) Sepharose and thus separated from more than 95% of the ribosomal RNA and transfer RNA. In these experiments, 65% of the early (3 to 5 hr postinfection) and 85% of the late (14 to 16 hr postinfection) virus-specific RNA was retained by the poly (U) Sepharose. Early in the infection 18%, and late in the infection more than 95%, of the poly (A)-containing fraction, eluted from the poly (U) Sepharose with 90% formamide, was adenovirus-specific, as shown by exhaustive hybridization. Different patterns, containing several distinct species of viral mRNA, were detected early and late in the infectious cycle. No distinct viral mRNA lacking poly (A) was discovered.

Adenoviridae↗