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Biomedical subjects

M C Niu

Publications and source records attributed to M C Niu.

At least 19 recordsLinked to original sources
PubMed1989

Transfer of information from mRNA to chromosomes by reverse transcription in early development of goldfish eggs.

In earlier publications, we have recorded evidence that micro-injection of globin mRNA from rabbit into goldfish eggs leads to the production of rabbit globin in mature red blood cells of goldfish. This paper is concerned with the mechanism of that apparent transfer of genetic information from the cytoplasm to the nucleus. We investigate the possibility that the injected mRNA is reverse transcribed to create a corresponding cDNA in goldfish eggs. By using purified mRNA from rabbit reticulocytes and micro-injection into enucleated and nucleated goldfish eggs, we show that the production of a DNA sequence hybridizes to cloned cDNA of rabbit globin mRNA and appears to become incorporated into the chromosomes of the developing eggs.

Animals↗
PubMed1987

Cytoplasmic effect on gene function in Xenopus laevis.

The pigmentation gene of Xenopus laevis is dominant and that of albino aP mutant recessive. Heterologous haploid hybrids are produced by UV inactivation of the egg nuclei during second polar body formation in the mutant sperm-fertilized Xenopus eggs. During development of these hybrids, melanin appeared in the eye and melanophores in the skin at stages comparable to those of the wild type, but much earlier than in the albino mutant. The number and intensity of pigment cells are intermediate between the black Xenopus and albino mutant. While a number of pigment cells remain in the hybrids, those in the albino eventually degenerate. Therefore, the development and maintenance of pigmentation in heterologous hybrids are contributed by Xenopus cytoplasm. Tadpole tail-tips were squashed and stained for chromosome counting. The results show that Xenopus and mutants are diploid (36 chromosomes) and heterologous haploid hybrids have 18 chromosomes.

Animals↗
PubMed1983

Re-examination of the DNA-mediated transformation in goldfish.

DNAs were isolated from goldfish, and the balancer bearing species of newt. They were injected separately into fertilized goldfish eggs. A balancer developed in some newt-DNA injected goldfish. DNA injected goldfish eggs occasionally developed a non-balancer process. These results demonstrated the newt DNA-mediated transfer of the species character from newt to goldfish. The injected DNA was localized by the method of autoradiography using H3-cDNA. Silver grains were found in areas over the colchicine induced metaphase. The incorporation of foreign DNA into chromosomes provides a material basis for genetic transformation.

Animals↗
PubMed1977

Albumin synthesis in mouse uterus in response to liver mRNA.

Messenger RNA was isolated, by means of its attachment to poly(A), from calf liver and the livers of mice, rats, and chickens. When injected into the uterine lumen of immature or spayed mice, both mouse albumin and the albumins characteristic of the species donating the mRNA were synthesized. Studies with inhibitors disclosed that puromycin blocked the synthesis of both albumin species, while dactinomycin affected only mouse albumin synthesis. It appears, therefore, that in the experimental situation used, the function of exogenous liver mRNA is 2-fold: (i) it programs the synthesis of alien albumin in uterine epithelial cells, and (ii) it stimulates the synthesis of mRNA in epithelial cells. The mRNA thus produced primes the synthesis of mouse albumin.

Albumins↗
PubMed1976

Messenger RNA induction of fast sodium ion channels in cultured cardiac myoblasts.

Incubation with adult heart messenger RNA caused the appearance of fast sodium ion channels in young myocardial cells whose development has been arrested in vitro. The induction was blocked by cycloheximide, indicating dependence on protein synthesis. Thus, cardiac myoblasts can be made to differentiate in vitro, and membrane properties can be altered by exogenous RNA.

Action Potentials↗
PubMed1975

Induction by RNA of inositol independence in Neurospora crassa.

The effect of purified wild-type RNA (allo-RNA) on genetic reversion of inositol-requiring mutant 89601 of Neurospora crassa is described. The mutant (inos minus) strain, on treatment with the wild-type RNA preparation, was found to revert to wild type (inos+) in significant numbers. RNA from the mutant (iso-RNA) and allo-RNA digested by RNase were ineffective in causing genetic reversion at the inositol locus. The allo-RNA-induced revertants were stable and showed a Mendelian transmission of the inos+ character.

Inositol↗