Biomedical subjects

D C Dobbertin

Publications and source records attributed to D C Dobbertin.

4 recordsLinked to original sources

PubMed1984

The glycoprotein that is transported between successive compartments of the Golgi in a cell-free system resides in stacks of cisternae.

Electron microscope autoradiography has been used to localize the glycoprotein transported between successive compartments of the Golgi in a cell-free system. Both donor and acceptor Golgi fractions contain stacks of cisternae, which remain as discrete populations even after prolonged incubations together. The glycosylated VSV G protein, having received 3H-GlcNAc residues following its transport in vitro, is entirely within the population of acceptor stacks from the uninfected wild-type Golgi population (those housing GlcNAc transferase l). Quantitation of 3H grains reveals between 6,000 and 12,000 molecules of G protein introduced into each acceptor cisterna as a result of transport in the cell-free system, amounting to approximately 5% of its total membrane protein. This represents about the full complement of transported protein normally contained in a Golgi cisterna in vivo. Transport in the cell-free system is efficient and specific, preserving the integrity of the Golgi stack and its individual cisternae.

Acetylglucosamine↗

PubMed1976

Relationships between intracisternal type A and extracellular oncornavirus-like particles produced in murine MOPC-460 myeloma cells.

Oncornavirus-like particles of the "A" (both intracisternal and intracytoplasmic) and "B" or "C" (extracellular) types are produced by murine MOPC-460 myeloma cells. This communication describes a comparative study on tracisternal A and extracellular particles. Both types of particles contain an RNA-dependent DNA polymerase activity, traces of 35S and 70 S RNA in addition to larger amounts of degraded RNA, and proteins of approximately 76,000 and 45, 000 daltons. The 76,000-dalton proteins from intracisternal A and extracellular particles have the same cyanogen bromide peptides. Hybridization kinetic analysis indicates that the RNAs in the two particles are identical or very closely related and share partial homology with Moloney leukemia virus RNA. In contrast, the particles appear to have little or no relationship to murine mammary tumor virus as judged by several different criteria. Electron microscope studies indicate that the extracellular particles arise from the budding of core components through the plasma membrane. These results suggest that the intracisternal A and extracellular oncornavirus-like particles produced by MOPC-460 cells are closely related.

Animals↗

PubMed1975

Reverse transcriptase associated with A-type particles from murine myeloma cells.

Our findings may be summarized as follows: (a) a DNA polymerase is associated with murine type A particles, which is very similar to the reverse transcriptases found in true RNA tumor viruses; (b) the majority of the RNA isolated from A particles is of low molecular weight (probably due to degradation), byt appears to contain an amount of unique sequence information comparable to that found in other oncornavirus particles. These results suggest that A-type particles may be very similar, and perhaps related, to the two other classes (B and C) of oncornaviruses.

Base Sequence↗

PubMed1975

Characterization of DNA polymerase and RNA associated with A-type particles from murine myeloma cells.

The RNA-dependent DNA polymerase present in intracisternal A-type particles from mouse myeloma tumor cells has been studied. This polymerase can use either endogenous A particle RNA or an exogenous synthetic polynucleotide [poly (rA)] as a template. The DNA reaction product is small (4S-10S) and over 90% of it hybridizes to A particle RNA, whereas up to 50% of it hybridizes to murine sarcoma-leukemia virus RNAs. The RNA isolated from purified A particles is generally of low molecular weight (5S-15S) but contains small amount of 70S and 35S components. These results suggest that A-type particles may be related to C-type oncornaviruses.

Animals↗