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Biomedical subjects

U Lindberg

Publications and source records attributed to U Lindberg.

141 records · Page 8Linked to original sources
PubMed1972

Characterization of messenger ribonucleoprotein and messenger RNA from KB cells.

Messenger ribonucleoprotein and mRNA from KB-cells were isolated under conditions designed to minimize nonspecific RNA-protein interaction and to minimize degradation by contaminating ribonucleases. A large fraction, 60-70%, of the messenger ribonucleoprotein from polysomes dissociated in vitro by either EDTA or puromycin sedimented faster than the large ribosome subunit. Messenger ribonucleoprotein particles with sedimentation coefficients up to 200 S were observed. Released mRNA was also large, with maximal molecular weights around 5 x 10(6).

Cell Fractionation↗
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↗
PubMed1970

SV40-specific RNA in the nucleus and polyribosomes of transformed cells.

Cells transformed by the oncogenic virus SV40 are known to contain viral DNA integrated into cellular DNA and to produce virus-specific RNA. It has been shown that nuclear molecules containing virus-specific sequences are considerably longer than presumed virus-specific mRNA molecules from cytoplasmic polyribosomes. This finding suggests the possibility that cytoplasmic mRNA is derived by the specific cleavage of larger nuclear RNA.

Animals↗
PubMed1970

Deoxyribonucleotide pools and deoxyribonucleic acid synthesis in mouse embryo cells infected with three classes of polyoma virus particles.

Polyoma virus particles were purified by equilibrium centrifugation in CsCl. Particles from three regions of the density gradient were examined for infectivity, for their ability to induce expanded pools of deoxyribonucleic acid (DNA) precursors, and for their ability to stimulate the synthesis of DNA. The most infectious population of particles, the virions, having a buoyant density of 1.33 g/ml, gave the greatest stimulation of the DNA-synthesizing apparatus of mouse embryo cells. Empty particles at density 1.29 g/ml had no DNA stimulatory activity. A population of particles of intermediate density, referred to as pseudovirions, was also much less active than virions in stimulating DNA synthesis, and the limited stimulatory activity of the latter fraction may be accounted for by its measured contamination with infective particles.

Animals↗
PubMedDate not supplied

Specific interaction between phosphatidylinositol 4,5-bisphosphate and profilactin.

There is evidence that the polymerization of actin takes place at the plasma membrane, and that profilactin (profilin/actin complex), the unpolymerized form of actin found in extracts of many non-muscle cells, serves as the immediate precursor. Both isolated profilin and profilactin interact with detergent when analysed by charge shift electrophoresis, indicating that they have amphipathic properties and may be able to interact directly with the plasma membrane. We demonstrate here that isolated profilin, as well as the profilactin complex, interacts with anionic phospholipids. Phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2) was found to be the most active phospholipid, causing a rapid and efficient dissociation of profilactin with a concomitant polymerization of the actin in appropriate conditions. These and other observations suggest the possibility of a relationship between the induction of actin filament formation and the increased activity in the phosphatidylinositol cycle seen as a result of ligand-receptor interactions in various systems.

Actins↗