Dataset Information

Studies on sex-organ development. Changes in chromatin structure during spermatogenesis in maturing rooster testis as demonstrated by the initiation pattern of ribonucleic acid synthesis in vitro.

ABSTRACT: To probe the structural change in the genome of the differentiating germ cell of the maturing rooster testis, the chromatin from nuclei at various stages of differentiation were transcribed with prokaryotic RNA polymerase from Escherichia coli or with eukaryotic RNA polymerase II from wheat germ. The transcription was performed under conditions of blockage of RNA chain reinitiation in vitro with rifampicin or rifampicin AF/013. With the E. coli enzyme, the changes in (1) the titration curve for the enzyme-chromatin interaction, (2) the number of initiation sites, (3) the rate of elongation of RNA chains, and (4) the kinetics of the formation of stable initiation complexes revealed the unmasking of DNA in elongated spermatids and the masking of DNA in spermatozoa. In both cases the stability of the DNA duplex in the initiation region for RNA synthesis greatly increased. In contrast with the E. coli enzyme, the wheat-germ RNA polymerase II was relatively inefficient at transcribing chromatin of elongated spermatids. Such behaviour can be predicted if unmasked double-stranded DNA is present in elongated spermatids.

SUBMITTER: Mezquita C

PROVIDER: S-EPMC1183885 | biostudies-other | 1978 Feb

REPOSITORIES: biostudies-other

ACCESS DATA

Similar Datasets

Project description:Assays of transcription in vitro, with Escherichia coli RNA polymerase or wheat-germ RNA polymerase II, were used to characterize chromatin templates isolated from the left Müllerian duct of the chick embryo during normal development, and during development in the presence of diethylstilboestrol. Control Müllerian-duct template capacity with E. coli RNA polymerase decreased from 6.42% on day 10 to 4.34% by day 15 of development. Similar results were found with wheat-germ RNA polymerase II. In the presence of rifampicin and heparin, the prokaryotic enzyme transcribed a number-average RNA chain of 670 nucleotide residues, at an average rate of 110 nucleotide residues/min, from Müllerian-duct chromatin of all developmental stages. From day 10 to day 15 there was a 44% decrease in the number of initiation sites for E. coli RNA polymerase on Müllerian-duct chromatin. A 47% decline was observed when these chromatins were transcribed with excess RNA polymerase II in the presence of rifamycin Af/013. Signs of increasing responsiveness to oestrogen developed between days 10 and 16. Embryos exposed to maximally responsive doses of diethylstilboestrol for 2 days showed increases in Müllerian-duct chromatin template capacity, RNA-chain initiation sites, wet weight, protein and RNA. The changes seen in the oviduct of the 1-week-old chick injected for 2 days with diethylstilboestrol were defined as 100% responses. By comparison, the Müllerian duct, after exposure to diethylstilboestrol from day 10 to day 12, from day 13 to day 15 or from day 16 to day 18, showed a 15%, 39% and 72% template response respectively, and a 42%, 56% and 85% initiation-site change respectively. A similar developmental trend was observed in all parameters. It is concluded that oestrogenic responsiveness in the developing Müllerian duct increases from day 10 to nearly maximal values by day 16 of development, and that this transition is paralleled by a progressive restriction of genomic activity.

Dataset Information

Studies on sex-organ development. Changes in chromatin structure during spermatogenesis in maturing rooster testis as demonstrated by the initiation pattern of ribonucleic acid synthesis in vitro.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets