THE EFFECTS OF GAMMA IRRADIATION OF HUMAN FIBROBLASTS ON HUMAN/CHINESE HAMSTER SOMATIC CELL HYBRIDS

1981 ◽  
Vol 23 (3) ◽  
pp. 505-511 ◽  
Author(s):  
L. J. Donald ◽  
H. S. Wang ◽  
N. J. Holliday ◽  
J. L. Hamerton

Human fibroblast cells were exposed to 0, 10, 20, or 40 Grays of gamma rays and then fused with unirradiated Chinese hamster cells deficient in HPRT. THAG selection system was used to ensure that only hybrid cell lines could survive. The time of appearance of pickable hybrid colonies and the frequency of dishes without any colonies were related to radiation dose. As the radiation dose increased, there was a positive correlation with frequency of cells with abnormal nuclei and a negative correlation with frequency of human chromosomes. Additionally, the hamster chromosomes had damage similar to that produced by radiation; the frequency of damaged hamster chromosomes was positively correlated with radiation dose.




1973 ◽  
Vol 20 (3) ◽  
pp. 195-202 ◽  
Author(s):  
Ans Jongsma ◽  
Harry Someren ◽  
Andries Westerveld ◽  
Ann Hagemeijer ◽  
Peter Pearson


1979 ◽  
Vol 38 (1) ◽  
pp. 391-403
Author(s):  
A. Rodgers

A method of measuring semi-quantitatively small amounts of human DNA in irradiated human × mouse and irradiated human × Chinese-hamster somatic cell hybrids is described. One method uses molecular hybridization of cell DNA bound to nitrocellulose filters with a cRNA probe to Cot 0–1 human DNA. Alternatively hybrid cell DNA is reassociated in solution with a Cot 0–1 fraction of nick-translated human DNA. Formamide buffers give specificity to the reaction. The detection limit of the filter method is 0.2–0.5% equivalents and reassociation kinetics 0.005–0.1% equivalents of a human genome. Experiments with cell hybrids suggest that a fragment of repetitive DNA may be retained along with the selected genes after a cell fusion. In one case however, of a hybrid cell in which malignancy is suppressed, highly repetitious sequences were not found.





1983 ◽  
Vol 157 (3) ◽  
pp. 1020-1027 ◽  
Author(s):  
S L Naylor ◽  
A Y Sakaguchi ◽  
T B Shows ◽  
M L Law ◽  
D V Goeddel ◽  
...  

A cDNA clone for human immune interferon (IFN-gamma) gene sequences, plasmid p69, was used to chromosomally map the IFN-gamma gene by detecting human IFN-gamma gene sequences in DNA isolated from human-rodent somatic cell hybrids. We were able to map the IFN-gamma gene by correlating the human chromosomes present in these hybrids with the human specific 8.8 and 2.0 kilobase pair fragments produced by EcoRI digestion of genomic DNA. Southern blot analysis of 37 hybrid cell lines indicated that the gene for IFN-gamma was on human chromosome 12. A hybrid containing a portion of chromosome 12 localized the IFN-gamma gene to the p1205 leads to qter region.





1986 ◽  
Vol 6 (10) ◽  
pp. 3428-3432
Author(s):  
D Karentz ◽  
J E Cleaver

Xeroderma pigmentosum (XP) is an autosomal recessive human disease, characterized by an extreme sensitivity to sunlight, caused by the inability of cells to repair UV light-induced damage to DNA. Cell fusion was used to transfer fragments of Chinese hamster ovary (CHO) chromosomes into XP cells. The hybrid cells exhibited UV resistance and DNA repair characteristics comparable to those expressed by CHO cells, and their DNA had greater homology with CHO DNA than did the DNA from XP cells. Control experiments consisted of fusion of irradiated and unirradiated XP cells and repeated exposure of unfused XP cells to UV doses used for hybrid selection. These treatments did not result in an increase in UV resistance, repair capability, or homology with CHO DNA. The hybrid cell lines do not, therefore, appear to be XP revertants. The establishment of these stable hybrid cell lines is an initial step toward identifying and cloning CHO DNA repair genes that complement the XP defect in human cells. The method should also be applicable to cloning genes for other diseases, such as ataxia-telangiectasia and Fanconi's anemia.



2002 ◽  
Vol 83 (7) ◽  
pp. 1759-1764 ◽  
Author(s):  
Isidro Hötzel ◽  
William P. Cheevers

The maedi–visna lentivirus (MVV) induces encephalitis, interstitial pneumonia, arthritis and mastitis in sheep. While some MVV strains can enter cells of ruminant species only, others can enter cells from many species, including human, but not Chinese hamster cells. However, the identity of the receptor(s) used by MVV for entry is unknown. The MVV-K1514 receptor gene was localized in sheep and human chromosomes using hamster×sheep and hamster×human hybrid cell lines. Based on entry by a vector pseudotyped with the MVV-K1514 envelope, the MVV-K1514 receptor gene was mapped to sheep chromosome 3p and to a region of human chromosome 2 (2p25>q13), which has conserved synteny with sheep chromosome 3p. These regions do not include any known lentivirus receptor or coreceptor gene, indicating that MVV-K1514 uses a new lentivirus receptor to infect human cells.



1983 ◽  
Vol 3 (5) ◽  
pp. 761-772
Author(s):  
S Chang ◽  
J J Wasmuth

Starting with hybrid cell lines between a Chinese hamster cell EmtA mutant and a Chinese hamster cell EmtB mutant, we have constructed cell lines that are homozygous for mutant alleles at both the emtA locus and the emtB locus, by using a two-step segregation protocol. The EmtA EmtB double mutants are approximately 10-fold more resistant to emetine inhibition than either of the parental mutants. Having both the EmtA mutation and the EmtB mutation expressed in the same cell also results in a level of resistance to cryptopleurine that is significantly higher than a simple additive effect of the two mutations alone. Analysis of ribosomal proteins by two-dimensional polyacrylamide gel electrophoresis demonstrated that a parental hybrid and a first-step segregant, which has lost the wild-type emtA allele, synthesize both a normal and an altered form of ribosomal protein S14, whereas an EmtA EmtB double mutant synthesizes only the altered form of this ribosomal protein. This result confirms that the emtB locus is the structural gene for ribosomal protein S14. Our results also suggest that the products of the emtA and emtB loci interact directly, indicating that the emtA locus, like the emtB locus, encodes a component of the ribosome.



1975 ◽  
Vol 17 (3) ◽  
pp. 307-325
Author(s):  
C.J. Marshall

A study has been made of the ribosomal RNA and chromosome constitution of man-mouse hybrid cells. Previous work has shown that no human 28s rRNA is detectable in man-mouse synkaryons. In general human chromosomes are lost from such hybrids. With a recently developed method for distinguishing mouse from human chromosomes, an analysis of various man-mouse hybrid cell lines has been made. This indicates that not all the human chromosomes bearing nucleolar organizers are lost in the hybrid cells and such loss cannot alone explain the absence of human 28s rRNA. An examination of the 28s rRNA synthesized by heterokaryons formed from several different parent cells has revealed that both parental types of 28s rRNA are present in heterokaryons. The control of rRNA synthesis in hybrid cells is discussed.



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