scholarly journals A COMPARISON BETWEEN HETEROGENEOUS NUCLEAR RNA AND POLYSOMAL MESSENGER RNA IN HELA CELLS BY RNA-DNA HYBRIDIZATION

1970 ◽  
Vol 44 (3) ◽  
pp. 467-475 ◽  
Author(s):  
Ruy Soeiro ◽  
James E. Darnell
Keyword(s):  
Hela Cell ◽  
Hela Cells ◽  
Dna Hybridization ◽  
Messenger Rna ◽  
Sequence Similarity ◽  
Nuclear Rna ◽  
Hybridization Reaction

Heterogeneous nuclear RNA (HnRNA) and mRNA from cytoplasmic polyribosomes of HeLa cells have been compared by RNA-DNA hybridization tests. 1 µg of HeLa cell DNA binds 0.05–0.10 µg of either HnRNA or mRNA. In addition, HeLa DNA that is preexposed to unlabeled HnRNA was found to have a reduced capacity to bind either HnRNA or mRNA. The results are compatible with considerable sequence similarity in the two types of RNA but, as is discussed, firm conclusions are precluded by imperfections of the hybridization reaction as presently employed.

scholarly journals A COMPARISON OF THE HETEROGENEOUS NUCLEAR RNA OF HELA CELLS IN DIFFERENT PERIODS OF THE CELL GROWTH CYCLE

1970 ◽  
Vol 44 (3) ◽  
pp. 476-483 ◽  
Author(s):  
Gerassimos N. Pagoulatos ◽  
James E. Darnell
Keyword(s):  
Cell Cycle ◽  
Cell Growth ◽  
Hela Cells ◽  
Dna Hybridization ◽  
Growth Cycle ◽  
Nuclear Rna

HeLa cells synthesize heterogeneous nuclear RNA (HnRNA) in the G1, S, and G2 portions of the cell cycle. HnRNA prepared from these various periods was compared by RNA-DNA hybridization experiments. The results indicated that some of the HnRNA molecules were equivalent at all times in the cell cycle, but limitations in the sensitivity of the hydridization reactions, as well as in the spectrum of hybridizing molecules, restrict the conclusions that can be drawn from these comparisons.

MITOCHONDRIAL PROTEIN SYNTHESIS IN HeLa CELLS

1973 ◽  
Vol 74 (Suppl) ◽  
pp. S263-S293 ◽  
Author(s):  
Giuseppe Attardi ◽  
Paolo Costantino ◽  
James England ◽  
Muriel Lederman ◽  
Deanna Ojala ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Hela Cell ◽  
Hela Cells ◽  
Messenger Rna ◽  
Polyacrylamide Gel Electrophoresis ◽  
Cell Mass ◽  
Mitochondrial Protein ◽  
Mitochondrial Protein Synthesis ◽  
Functional Protein ◽  
Strong Constraint

ABSTRACT HeLa cell mitochondrial polysomes, estimated to consist of two to seven 60S monomers, exhibit an unusual resistance to RNase and EDTA, possibly related to the strongly hydrophobic nature of their polypeptide products which makes the nascent chains particularly "sticky". Mitochondria-specific ribosomal and 4S RNA are coded for by mitochondrial DNA (mit-DNA): there is one gene for each ribosomal RNA (rRNA) species and nine genes for 4S RNA on the heavy (H) mit-DNA strand, and three 4S RNA genes on the light (L) strand. The existence of messenger RNA (mRNA) transcribed from mit-DNA is strongly suggested by the occurrence in mitochondria of poly(A) stretches, 60 to 80 residues long, most of which are covalently linked to RNA molecules coded for by mit-DNA. Mitochondrial poly(A) is not a transcription product of mit-DNA. The in vivo and in vitro products of mitochondrial protein synthesis exhibit by polyacrylamide gel electrophoresis a group of not well resolved components in the molecular weight range from 12 000 to 25 000 daltons, and another group, more abundant, in the range from 40 000 to 55 000 daltons. A strong constraint appears to exist in the pattern of amino acid utilization by HeLa cell mitochondria, with a very low level, if any, of incorporation of the charged polar amino acids, and a predominant utilization of the most hydrophobic ones. Block of mitochondrial protein synthesis by chloramphenicol for up to four generations of cell growth has no effect on mitochondrial growth and replication, on the rate of mitochondrial nucleic acid synthesis, and on the formation of a functional protein synthesizing apparatus; however, mitochondrial protein synthesis is required for the formation of a functional cytochrome c oxidase. No significant differences in the rate of mitochondrial protein synthesis per unit of cell mass, nor in the size distribution of the protein products, were found in HeLa cells in different phases of the cell cycle.

Complementarity between messenger RNA and nuclear RNA from HeLa cells

1972 ◽  
Vol 49 (1) ◽  
pp. 217-224 ◽  
Author(s):  
Martha Stampfer ◽  
Michael Rosbash ◽  
Alice S. Huang ◽  
David Baltimore
Keyword(s):  
Hela Cells ◽  
Messenger Rna ◽  
Nuclear Rna

Sequence similarity between heterogeneous nuclear RNA and polysomal messenger RNA in higher plants

FEBS Letters ◽  
1972 ◽  
Vol 23 (1) ◽  
pp. 65-68 ◽  
Author(s):  
M. Teissere ◽  
P. Penon ◽  
J. Ricard ◽  
G. Ratle
Keyword(s):  
Messenger Rna ◽  
Higher Plants ◽  
Sequence Similarity ◽  
Nuclear Rna

scholarly journals The effect of ribonuclease on polysomes and ribosomes of bacteria and animal cells

1968 ◽  
Vol 107 (4) ◽  
pp. 481-489 ◽  
Author(s):  
M. L. Fenwick
Keyword(s):  
Escherichia Coli ◽  
Hela Cell ◽  
Hela Cells ◽  
Messenger Rna ◽  
Animal Cells ◽  
E Coli

The mildest treatment with ribonuclease that causes any disaggregation of the polysomes of Escherichia coli or HeLa cells simultaneously attacks the RNA of the constituent ribosomes. It is concluded that the susceptibility to ribonuclease of polysomes does not suggest that they are held together by a strand of messenger RNA. The RNA of the larger sub-unit of bacterial ribosomes has particularly sensitive regions resulting in a non-random degradation. The RNA of the smaller sub-unit of E. coli ribosomes is relatively resistant to ribonuclease attack. The same may be true of the respective sub-units of the intact HeLa-cell ribosome, but both sub-units become very sensitive to ribonuclease on dissociation from each other.

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