Marker segregation without chromosome loss at theemt locus in Chinese hamster cell hybrids

1980 ◽  
Vol 6 (2) ◽  
pp. 199-213 ◽  
Author(s):  
Ronald G. Worton ◽  
Catherine Duff ◽  
Christine E. Campbell
Keyword(s):  
Chinese Hamster ◽  
Chinese Hamster Cell ◽  
Chromosome Loss ◽  
Cell Hybrids

Segregation of recessive phenotypes in somatic cell hybrids: role of mitotic recombination, gene inactivation, and chromosome nondisjunction

1981 ◽  
Vol 1 (4) ◽  
pp. 336-346
Author(s):  
C E Campbell ◽  
R G Worton
Keyword(s):  
Somatic Cell ◽  
Chinese Hamster ◽  
Mitotic Recombination ◽  
Chinese Hamster Cell ◽  
Gene Inactivation ◽  
Chromosome Loss ◽  
Resistance Locus ◽  
Chromosome 2 ◽  
Somatic Cell Hybrids ◽  
Cell Hybrids

Somatic cell hybrids heterozygous at the emetine resistance locus (emtr/emt+) or the chromate resistance locus (chrr/chr+) are known to segregate the recessive drug resistance phenotype at high frequency. We have examined mechanisms of segregation in Chinese hamster cell hybrids heterozygous at these two loci, both of which map to the long arm of Chinese hamster chromosome 2. To follow the fate of chromosomal arms through the segregation process, our hybrids were also heterozygous at the mtx (methotrexate resistance) locus on the short arm of chromosome 2 and carried cytogenetically marked chromosomes with either a short-arm deletion (2p-) or a long-arm addition (2q+). Karyotype and phenotype analysis of emetine- or chromate-resistant segregants from such hybrids allowed us to distinguish four potential segregation mechanisms: (i) loss of the emt+- or chr+-bearing chromosome; (ii) mitotic recombination between the centromere and the emt or chr loci, giving rise to homozygous resistant segregants; (iii) inactivation of the emt+ or chr+ alleles; and (iv) loss of the emt+- or chr+-bearing chromosome with duplication of the homologous chromosome carrying the emtr or chrr allele. Of 48 independent segregants examined, only 9 (20%) arose by simple chromosome loss. Two segregants (4%) were consistent with a gene inactivation mechanism, but because of their rarity, other mechanisms such as mutation or submicroscopic deletion could not be excluded. Twenty-one segregants (44%) arose by either mitotic recombination or chromosome loss and duplication; the two mechanisms were not distinguishable in that experiment. Finally, in hybrids allowing these two mechanisms to be distinguished, 15 segregants (31%) arose by chromosome loss and duplication, and none arose by mitotic recombination.

Chromosome loss is responsible for segregation at theHPRT locus in Chinese hamster cell hybrids

1977 ◽  
Vol 3 (5) ◽  
pp. 539-551 ◽  
Author(s):  
Sandra A. Farrell ◽  
Ronald G. Worton
Keyword(s):  
Chinese Hamster ◽  
Chinese Hamster Cell ◽  
Chromosome Loss ◽  
Cell Hybrids

scholarly journals Segregation of recessive phenotypes in somatic cell hybrids: role of mitotic recombination, gene inactivation, and chromosome nondisjunction.

1981 ◽  
Vol 1 (4) ◽  
pp. 336-346 ◽  
Author(s):  
C E Campbell ◽  
R G Worton
Keyword(s):  
Somatic Cell ◽  
Chinese Hamster ◽  
Mitotic Recombination ◽  
Chinese Hamster Cell ◽  
Gene Inactivation ◽  
Chromosome Loss ◽  
Resistance Locus ◽  
Chromosome 2 ◽  
Somatic Cell Hybrids ◽  
Cell Hybrids

Somatic cell hybrids heterozygous at the emetine resistance locus (emtr/emt+) or the chromate resistance locus (chrr/chr+) are known to segregate the recessive drug resistance phenotype at high frequency. We have examined mechanisms of segregation in Chinese hamster cell hybrids heterozygous at these two loci, both of which map to the long arm of Chinese hamster chromosome 2. To follow the fate of chromosomal arms through the segregation process, our hybrids were also heterozygous at the mtx (methotrexate resistance) locus on the short arm of chromosome 2 and carried cytogenetically marked chromosomes with either a short-arm deletion (2p-) or a long-arm addition (2q+). Karyotype and phenotype analysis of emetine- or chromate-resistant segregants from such hybrids allowed us to distinguish four potential segregation mechanisms: (i) loss of the emt+- or chr+-bearing chromosome; (ii) mitotic recombination between the centromere and the emt or chr loci, giving rise to homozygous resistant segregants; (iii) inactivation of the emt+ or chr+ alleles; and (iv) loss of the emt+- or chr+-bearing chromosome with duplication of the homologous chromosome carrying the emtr or chrr allele. Of 48 independent segregants examined, only 9 (20%) arose by simple chromosome loss. Two segregants (4%) were consistent with a gene inactivation mechanism, but because of their rarity, other mechanisms such as mutation or submicroscopic deletion could not be excluded. Twenty-one segregants (44%) arose by either mitotic recombination or chromosome loss and duplication; the two mechanisms were not distinguishable in that experiment. Finally, in hybrids allowing these two mechanisms to be distinguished, 15 segregants (31%) arose by chromosome loss and duplication, and none arose by mitotic recombination.

Asynchronous DNA replication and asymmetrical chromosome loss in Chinese hamster-mouse somatic cell hybrids

1976 ◽  
Vol 2 (1) ◽  
pp. 1-10 ◽  
Author(s):  
T. Labella ◽  
G. Colletta ◽  
G. Marin
Keyword(s):  
Dna Replication ◽  
Somatic Cell ◽  
Chinese Hamster ◽  
Chromosome Loss ◽  
Somatic Cell Hybrids ◽  
Cell Hybrids ◽  
Mouse Somatic Cell

Genetics of Somatic Mammalian Cells: Linkage Studies with Human–Chinese Hamster Cell Hybrids

Nature ◽  
1970 ◽  
Vol 228 (5269) ◽  
pp. 329-332 ◽  
Author(s):  
FA-TEN KÁO ◽  
THEODORE T. PUCK
Keyword(s):  
Mammalian Cells ◽  
Chinese Hamster ◽  
Chinese Hamster Cell ◽  
Linkage Studies ◽  
Cell Hybrids

Genetic demonstration of mitotic recombination in cultured chinese hamster cell hybrids

Cell ◽  
1984 ◽  
Vol 36 (3) ◽  
pp. 697-707 ◽  
Author(s):  
John J. Wasmuth ◽  
Linda Vock Hall
Keyword(s):  
Chinese Hamster ◽  
Mitotic Recombination ◽  
Chinese Hamster Cell ◽  
Cell Hybrids

Chromosome segregation from cell hybrids.II. Do differences in parental cell growth rates and phase times determine direction of loss?

1986 ◽  
Vol 28 (5) ◽  
pp. 735-743 ◽  
Author(s):  
Jennifer A. Marshall Graves ◽  
Jaclyn M. Wrigley
Keyword(s):  
Cell Cycle ◽  
Chromosome Segregation ◽  
Chinese Hamster ◽  
Parental Cell ◽  
S Phase ◽  
Chromosome Loss ◽  
Parent Cell ◽  
Cycle Times ◽  
Cell Hybrids ◽  
The One

The hypothesis that the direction of chromosome segregation in cell hybrids is determined by the interaction of parent cell cycles, or S-phase times, predicts that the segregant parent will always be the one with the longer cycle, or the longer S phase, and that late replicating chromosomes will be more frequently lost. We have tested this hypothesis by studying cell cycle parameters of mouse, Chinese hamster, and platypus parent cells and by observing chromosome loss and replication patterns in hybrids between them. Two types of hybrids have been studied: mouse–hamster hybrids showed gradual segregation, in one or other direction, of 10–60% chromosomes, while rodent–platypus hybrids (which could be selected under conditions optimal for either parent cell) showed rapid and extreme segregation of platypus chromosomes. We found no correlation between the direction of segregation and the relative lengths of parental cycle times, or phase times, nor between sequence of replication and frequency with which segregant chromosomes are lost. We therefore conclude that the direction and extent of segregation is not directly determined by the interaction of parental cycle or phase times.Key words: cell hybrids, chromosome loss, cell cycle, S phase.

Changes in the cell cycle during culture of mouse-Chinese hamster cell hybrids

1980 ◽  
Vol 102 (2) ◽  
pp. 209-216 ◽  
Author(s):  
Jennifer A. Marshall Graves ◽  
Kenneth W. Koschel
Keyword(s):  
Cell Cycle ◽  
Chinese Hamster ◽  
Chinese Hamster Cell ◽  
Cell Hybrids

Chromosome segregation from cell hybrids. I. The effect of parent cell ploidy on segregation from mouse – Chinese hamster hybrids

1984 ◽  
Vol 26 (5) ◽  
pp. 557-563 ◽  
Author(s):  
Jennifer A. Marshall Graves
Keyword(s):  
Chromosome Number ◽  
Chromosome Segregation ◽  
Chinese Hamster ◽  
Chromosome Loss ◽  
Parent Cell ◽  
Cell Hybrids ◽  
Parental Factor ◽  
Species Combination ◽  
Mouse Cells ◽  
Input Ratio

To determine whether the dosage of some parental factor influences the direction and extent of chromosome segregation, I have constructed hybrids between polyploid series of mouse and Chinese hamster lines. The input ratio of mouse: hamster chromosomes varied from 3.3 (in hybrids between diploid hamster and polyploid mouse cells) and 0.9 (in hybrids between polyploid hamster and near-diploid mouse cells). Mouse chromosomes were retained and hamster chromosomes were lost from all hybrids with input ratios ≥ 1.3; the extent of hamster chromosome loss increased from 25 to 60% as the proportion of mouse chromosomes was increased. Reverse segregation was observed in hybrids in which the ratio was 0.9; hybrids between polyploid hamster and diploid mouse cells retained most hamster chromosomes and lost 52% of mouse chromosomes. I conclude that the direction and extent of chromosome segregation from these hybrids depends on the dosage of some factor contained in the parent cells; because the volumes of polyploid cells are proportional to chromosome number, this factor could be chromosomal, nuclear, or cytoplasmic. Dosage differences should therefore be considered when comparing chromosome segregation from hybrids with cells of the same species combination, but which might differ in chromosome number (e.g., diploid lines and established lines), or cell volume (e.g., cells from different tissues).Key words: cell hybrids, mouse – hamster, segregation, chromosome loss, ploidy.

Sign in / Sign up

Export Citation Format

Share Document