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W B Upholt

Publications and source records attributed to W B Upholt.

67 records · Page 4Linked to original sources
PubMed1979

Translation and characterization of messenger RNAs in differentiating chicken cartilage.

Total RNA, prepared from chicken limb bud cultures undergoing differentiation to cartilage, has been translated in a wheat germ cell-free protein-synthesizing system. Antibodies against chondroitin sulfate proteoglycan core protein immunoprecipitate a single component which migrates as a protein of 340,000 daltons in sodium dodecyl sulfate/polyacrylamide gels. The messenger RNA for this protein sediments at approximately 27 S in 70% formamide or aqueous sucrose gradients. The 340,000-dalton protein is present in cell-free translation products directed by RNA prepared from limb bud cultures and sternae and is absent in cell-free translation directed by RNA prepared from embryonic calvaria or liver. The level of synthesis of this protein is greatly reduced when RNA prepared from limb bud cultures inhibited from differentiation by BrdUrd is used. (Pre)pro alpha 1(I), -alpha 2(I), and -alpha 1(II) collagen bands have been identified on gels by electrophoresis of collagenase-digested or immunoprecipitated cell-free translation products directed by RNA from differentiating limb bud cultures, embryonic sternae, and embryonic calvaria.

Animals↗
PubMed1977

Superhelix densities of circular DNA's: a generalized equation for their determination by the bouyant method.

Equations for the measurement of the supertwisting of circular DNA's from banding positions in buoyant density gradients containing intercalating dyes have required the use of SV40 DNA isolated from virions as a reference DNA. These equations are modified to allow the use of any closed circular DNA of known superhelix density as a reference DNA.

Centrifugation, Density Gradient↗
PubMed1977

Mapping of mitochondrial DNA of individual sheep and goats: rapid evolution in the D loop region.

Mitochondrial DNA (mtDNA) from sheep and goat was compared by restriction endonuclease analysis and heteroduplex mapping in the electron microscope. The fragment patterns produced by endonuclease Hae III from three individual sheep and two goat mtDNAs all differed from each other. The three sheep mtDNAs had identical Eco RI and Hind III fragments, but the two goat mtDNA patterns differed from each other as well as from sheep mtDNA. We estimate that each sheep mtDNA differs from each other by 0.5-1% of its nucleotide sequences, the two goat mtDNAs by 1-2%, and there is a 6-11% sequence difference between sheep and goat mtDNAs. We have mapped the Eco RI and Hind III sites of goat and sheep mtDNA and determined the positions of the D loop, which marks the replication origin, relative to the restriction map. The D loops are at homologous positions on the mtDNAs from both species, but the goat D loop is only 75% as long as the sheep D loop. Regions with a high degree of sequence divergence occur at both ends of the D loop. We suggest that a duplication of about 150 base pairs has occurred in the region where the sheep and goat D loops differ in length. We discuss mtDNA evolution in terms of divergence of isolated "mitochondrial DNA clones."

Animals↗
PubMed1977

Estimation of DNA sequence divergence from comparison of restriction endonuclease digests.

An estimation of the DNA sequence divergence between defined DNA secquences of individuals or species may be made from comparison by gel electrophoresis of restriction endonuclease digests. This analysis is applicable to purified DNA sequence of moderate complexity (1-100 X 10(6) daltons) which have diverged by base substitution of 0.5 to 25% of nucleotides.

Base Sequence↗
PubMed1974

Accumulation of replicative intermediates of mitochondrial DNA in Tetrahymena pyriformis grown in ethidium bromide.

The effect of growth of Tetrahymena pyriformis in ethidium bromide (EthBr) on the structure and synthesis of mitochondrial DNA (mtDNA) has been investigated. During the first 5 h of growth in EthBr, mtDNA synthesis is inhibited 95% or more. After 10-15 h, this block is partially released and large numbers of replicating molecules accumulate, indicating that inhibition by EthBr primarily affects the rate of chain growth and not the initiation of new rounds of replication. The accumulated molecules sediment more rapidly than normal Tetrahymena mtDNA and do not contain enough single-strand regions to distinguish them from normal Tetrahymena mtDNA when banded in buoyant CsCl or NaI gradients. Electron microscopy shows that the predominant species in this rapidly sedimenting DNA is a linear molecule containing one symmetrical double-stranded replication loop of varying size located at its center. No degradation of mtDNA from cells grown in EthBr was detected in alkaline velocity gradients.

Animals↗
PubMed1969

The use of an ethidium analogue in the dye-buoyant density procedure for the isolation of closed circular DNA: the variation of the superhelix density of mitochondrial DNA.

The separation between open and closed circular DNA in buoyant CsCl gradients containing intercalating dyes depends on the superhelix density of the closed form. These separations are about 1.8 times larger with propidium iodide than with ethidium bromide. The superhelix densities of mitochondrial DNA from HeLa cells and Lytechinus pictus eggs appear to be about two thirds that of mitochondrial DNA from rat and rabbit liver.

Animals↗