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Biomedical subjects

A V Rake

Publications and source records attributed to A V Rake.

15 recordsLinked to original sources
PubMed1993

Altered nucleosome spacing associated with Down syndrome.

Micrococcal nuclease digestions of human leukocytes were analyzed using gel electrophoresis. The relative size (or average number of nucleotides) of nucleosomes was determined. The mean nucleosome size of the normal 46 chromosome karyotype is 185 +/- 2 bp. There was no significant variation in nucleosome size within the normal population due to age, sex, or race. The mean nucleosome size of the Down syndrome samples is 173 +/- 3 bp. These two groups have separate normal distribution curves which do not overlap and are significantly different at P < 0.1%.

Adolescent↗
PubMed1990

Nucleosome unit repeat size in aneuploid mice.

Male 8-day-old mice that have part of chromosome 7 translocated to an X chromosome [T(X;7)1 Ct] and that are chromosomally unbalanced for chromosome 7, and consequently trisomic for that part of chromosome 7, were found to have a smaller nucleosome repeat unit size than normal littermate males (Rake, A. V., and Edwards, R. H., Biochem. Genet. 25:671, 1987). This smaller nucleosome size is maintained in adult trisomic males. Males with a balanced chromosomal translocation [T(X;7)1Ct] had a normal nucleosome size compared to their littermates. The nucleosome unit size is not altered in two other types of aneuploid mice studied (XO vs XX, 2n = 39 and 40, respectively; and Ts12(17) vs normal, 2n = 40 and 41, respectively).

Aneuploidy↗
PubMed1989

Effect of a partial trisomy in the mouse upon cellular and nuclear RNA.

In a previous paper (Rake and Edwards, 1987) it was shown that the majority of the chromatin from trisomic mouse cells has nucleosomes with a smaller repeat length of DNA than the nucleosome repeat length of normal cells. Here it is shown that the RNA content of the total cell and of the nuclei is the same in all tissues studied, in both normal and trisomic cells. However, the amount per unit time or rate of RNA synthesis is depressed in the trisomic liver and brain nuclei. The depression of RNA synthesis could not be specified to the small trisomic section of the chromatin but instead must reflect the overall nuclear activity. These results, along with those of Devlin et al. (1988), indicate that the trisomic condition alters a substantial part of nuclear organization and activity, not just the small trisomic part.

Animals↗
PubMed1987

Altered chromatin structure associated with a partial trisomy of chromosome 7 in the mouse.

The chromatin of a mouse that is trisomic for part of chromosome 7 was investigated. Chromatin from trisomic tissue has a smaller average nucleosome DNA repeat length than chromatin from tissue taken from normal diploid littermates. DNA of the nucleosome cores is the same size in both normal and trisomic tissues. Not all of the nucleosome monomers have different repeat lengths. Normal and trisomic mouse kidney cells in tissue culture maintained their nucleosome repeat-length differences.

Animals↗
PubMed1980

Reassociation Kinetics and Cytophotometric Characterization of Peanut (Arachis hypogaea L.) DNA.

The base composition of peanut (var. NC-17) DNA determined from thermal denaturation profiles showed an average guanine plus cystosine content of 34% which was in close approximation to 36% guanine plus cytosine calculated from the buoyant density. Buoyant density also indicated the absence of satellite DNA. The genome size, 2.0 x 10(9) base pairs, as determined by reassociation kinetics of the single copy DNA was close to the genome size determined by cytophotometry, 2.1 x 10(9) base pairs. Peanut DNA averaging 450 to 600 base pairs long, reassociated in phosphate buffer and fractionated by hydroxylapatite, indicated a DNA genome composition of 36% nonrepetitive or single copy DNA; reassociation in formamide and followed by optical methods indicated the repetitive DNA possesses highly repeated, intermediately repeated and rarely repeated components of DNA with DNA sequences repeated on the average about 38,000, 6,700, and 200 times each. Different criteria of reassociation in formamide revealed further subdivisions of these four separate components of DNA. The DNA of above mentioned NC-17 variety compared to Florigiant variety showed no differences in thermal denaturation profiles, buoyant density, or in genome size.

Journal Article↗
PubMed1976

Structure of Caulobacter deoxyribonucleic acid.

The deoxyribonucleic acid of the dimorphic bacterium Caulobacter crescentus contains a component that renatures with rapid, unimolecular kinetics. This component was present in both swarmer and stalked cells and exhibited the sensitivity to endonuclease S1 expected for hairpin loops. Double-stranded side branches between 100 and 600 nucleotide pairs in length were visible in electron micrographs of rapidly reassociating deoxyribonucleic acid isolated by hydroxyapatite chromatography. No extrachromosomal elements were found in spite of systematic attempts to detect their presence. These results indicate that the rapidly reassociating fraction derives from inverted repeat sequences within the chromosome and not from cross-links or plasmids. We estimate that there are approximately 350 inverted repeat regions per Caulobacter genome. The kinetic complexity of Caulobacter deoxyribonucleic acid, however, is no greater than that of other bacteria.

Bacteria↗
PubMed1971

Transcription of nonrepeated DNA in neonatal and fetal mice.

The transcription of nonrepeated DNA sequences was measured by hybridization of RNA from neonatal and fetal mice to mouse DNA using three different techniques. The measurements indicate that a large part (about 70%) of the rapidly-labeled fetal RNA is transcribed from nonrepeated DNA sequences. It appears that more than 12% of the single-copy DNA sequences are represented in the RNA of newborn mice.

Animals↗