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J Gaubatz

Publications and source records attributed to J Gaubatz.

10 recordsLinked to original sources
PubMed1996

Interaction of apolipoprotein[a] with apolipoproteinB-100 Cys3734 region in lipoprotein[a] is confirmed immunochemically.

Monospecific polyclonal antibodies (MPAbs) to apoB-100 regions Cys3734 and Cys4190 were isolated by affinity chromatography using the synthetic polypeptides, Q3730VPSSKLDFREIQIYKK3746 and G4182IYTREELSTMFIREVG4198, respectively, coupled to a hydrophilic resin. Molecular modeling and fluroescence labeling studies have suggested that Cys67 located in kringle type 9 (LPaK9, located between residues 3991 and 4068 of the apo[a] sequence inferred by cDNA) of the apo[a] molecule is disulfide linked to Cys3734 of apoB-100 in human lipoprotein[a] (Lp[a]). This possibility has been further explored with MPAbs. Four species of MPAbs directed to a Cys3734 region of apoB-100 (3730-3746) were isolated from goat anti-human LDL serum by a combination of synthetic peptide (Q3730VPSSKLDFREIQIYKK3746) affinity chromatography and preparative electrophoresis (electrochromatography). MPAbs to the Cys4190 region of apoB-100, a second or alternative disulfide link-site between apo[a] and apoB-100, were also isolated using a synthetic peptide (G4182IYTREELSTMFIREVG4198) affinity resin. Results of immunoassays showed that binding of these four MPAbs to Lp[a] was significantly lower than to LDL. In contrast, MPAbs to the apoB-100 region 4182-4198 which contains Cys4190, a second or alternative disulfide link-site between apo[a] and apoB-100, displayed a less significant difference in binding to Lp[a] and LDL. These results provide additional evidence that the residues 3730-3746 of apoB-100 interact significantly with apo-a- in Lp-a-, and that Cys3734 is a likely site for the disulfide bond connecting apo[a] and apoB-100.

Amino Acid Sequence↗
PubMed1981

Nucleotide sequence for a novel duck alpha-globin gene.

Nucleotide sequence analysis of a recombinant cDNA for a duck alpha-globin gene indicates a gene with novel features and evolutionary history. The duck alpha-globin double-stranded cDNA, treated with S1 nuclease and tailed with poly(dC), was inserted into the PstI restriction endonuclease site of pBR322 tailed with poly(dG). Nucleotide sequence analysis of the resulting recombinant cDNA indicates that it contains the translated region and all of the 3' untranslated region for an alpha-globin gene. The sequence was determined by procedures designed especially for rapid analysis of pBR322 (PstI site) recombinant cDNAs. This duck globin has sequences related to the chicken alpha-A globin in some regions but in other regions it is more closely related to another alpha globin found in anemic chickens.

Amino Acid Sequence↗
PubMed1979

Nuclease digestion studies of mouse chromatin as a function of age.

Chromatin is organized into a repeating structure (nucleosome) made up of proteins and DNA. Micrococcal nuclease and DNAase I have been used to probe this structure in nuclear populations from three tissues (liver, brain and heart) of the inbred mouse strain C57BL at different ages. For those parameters examined in each tissue, chromatin contained essentially the same features of nucleosomal organization, regardless of the age of the mouse. Thus, the rate and extent of nuclease digestion, the size of the DNA repeat unit and nucleosome core are not significantly different as a function of age. However, the accessibility of internucleosomal DNA to micrococcal nuclease, as determined by measuring the DNA size distribution after nuclease cutting, may be partially limited in brain chromatin (but not liver or heart) of older animals. These results indicate that there are no gross, age-related changes in the conformational state or organization of chromatin in these tissues. The results do not exclude smaller alterations in chromatin which might occur with age and which the methodology employed might not be sensitive enough to detect.

Aging↗
PubMed1979

The structural organization of mouse chromatin as a function of age.

Chromatin is organized into a repeating structure (nucleosome) made up of proteins and DNA. Micrococcal nuclease and DNAase I have been used to probe this structure in nuclear populations from three tissues (liver, brain, and heart) of the inbred mouse strain C57BL at different ages. For those parameters examined, for each tissue, chromatin contained essentially the same features of nucleosomal organization, regardless of the age of the mouse. Thus, the rate and extent of nuclease digestion and the size of the DNA repeat unit and nucleosome core are not significantly different as a function of age. However, the accessibility of internucleosomal DNA to micrococcal nuclease, as determined by measuring the DNA size distribution after nuclease cutting, may be partially limited in chromatin of brain (but not liver or heart) of older animals. These results indicate that there are no gross, age-related changes in the conformational state or organization of chromatin in these tissues. The results do not exclude smaller alterations in chromatin that might occur with age, which the current methodology might not be sensitive enough to detect.

Aging↗
PubMed1976

Ribosomal RNA gene dosage as a function of tissue and age for mouse and human.

The average number of rRNA genes per haploid genome (rRNA gene dosage) of the cells present in liver and brain was determined throughout the lifespan of the inbred C57BL/6J mouse strain and of human. Ribosomal RNA gene dosage was determined using the RNA-excess DNA - RNA hybridization technique. DNA was extracted and purified using a CsCl/chloroform method with a high percent yield (over 90%) to minimize any possible effects of tissue and age-dependent selective loss or gain of rRNA genes. Radioactive rRNA was from the liver of the youngest age group for either mouse or human in all hybridization experiments, with DNA from the different tissues and age groups being the only variable. In the young mouse (35-49 days), the rRNA gene dosage was 36% higher in brain (114 genes), as compared to liver (84 genes). The rRNA gene dosage remained essentially constant as a function of age for mouse brain; but between the age of about 220 to 440 days, it increased in liver, attaining approximately an equal value to that of brain. No significant difference was found in the rRNA gene dosage of brain or liver between different mice of the same age. In contrast to this result, a significant difference was found between human tissues of similar age. The rRNA gene dosage ranged about 2-fold (148-289) between 2 months to 75 years of age. An age-dependent trend, similar to that for mouse liver, was found when the averages of four different age groups totaling 20 individuals were compared. However, this was not statistically significant. No difference in the rRNA gene dosage as a function of sex or tissue was apparent. Several models are discussed to account for these results.

Aging↗
PubMed1975

Hybridization of ribosomal RNA labeled to high specific radioactivity with dimethyl sulfate.

RNA radioactively methylated with dimethyl sulfate has the advantage of relatively low background noise level when utilized in DNA saturation hybridization employing the membrane filter technique. In addition, the RNA can be methylated with either 3H- or 14C-labeled methyl groups. However, the low specific radioactivity usually obtained with dimethyl sulfate has limited the use of this labeling technique. We describe a detailed characterization of the methylation of rRNA with dimethyl sulfate giving specific radioactivities on the order 10-5 cpm/mug. Kinetics and optimum conditions for the methylation reaction of rRNA were studied. The methylation did not cause excessive degradation of RNA in neutral aqueous solution, and the methyl derivative of RNA was stable under normal hybridization conditions. Specific radioactivitiy of the methylated RNA was found to be a linear function of the product of RNA concentration and specific radioactivity of the dimethyl sulfate in the reaction mixture at a constant incubation time. The methylated bases of the RNA lowered the thermal stability of the DNA-RNA hybrids by 1 degree in Tm per 1.6 per cent methylated RNA bases. rRNA gene dosage values using high specific radioactive methylated RNA were found to be 81 and 180 genes/haploid genome, respectively. Dissociation constants of the hybridization reaction ranged from 0.90 times 10-10 to 2.37 times 10-10 M.

Animals↗