Somatic cell fusion

The cultivated potato and many of its relatives are amenable to eell and tissue culture procedures, ineluding protoplast isolation and fusion. Somatic cell fusions have frequently been used to eombine the genomes of Solarium speeies that are sexually ineompatible because of pollen-stylar interactions or mismatched EBN numbers. Somatic fusion circumvents sexual reproduetion and results in novel eombinations of not only nuclear genomes, but also cytoplasmic genomes (Trabelsi et al., 2005 Bidani et al., 2007 Lovene et al., 2007). However, recalcitrant genotypes... 

Spontaneous fusion of cultured cells occurs only rarely. However, the rate at which it happens can be markedly increased by the addition of certain viruses or chemical fusogens to the culture. Sendai virus, as used in early somatic cell fusions, has a lipoprotein envelope similar in structure to the animal cell membrane. It has been suggested that a glycoprotein in the envelope promotes cell fusion by an as yet unexplained mechanism. 

Monoclonal antibodies (MAbs) produced through the technique of somatic cell fusion are fundamental tools in the exploration of chemokine biology. This chapter details the procedures that were used to generate a panel of MAbs directed against the human chemokine RANTES (1,2). The general approach described here should be broadly applicable to the generation of MAbs directed against other members of this cytokine family. 

Combination of atrazine resistance and cytoplasmic male sterility in rapeseed. Transfer of atrazine resistant chloroplasts from bird s rape (B. oapestris) into oilseed rape has been accomplished by back-crossTng (s this volume). The purpose achieved by somatic cell fusion was to combine the atrazine-resistant chloroplasts carried by a B. napus line with cytoplasmic male sterility (CMS), a mitoohondrlal tralt (l9). The CMS trait was carried by a B. napus line with the cytoplasm of radish (Raphanus sativus). Since both traits, atrazine resistance and CMS, are maternally inherited in sexual crosses, the only way to combine the traits was by protoplast fusion. The desired atrazine-resistant cybrids were identified in a randomly regenerated sample of plants by the presence of the CMS flower morphology and their darker green color at low temperature. Somatic hybrids rather than cybrids were obtained in each clone since no irradiation had been used to facilitate the elimination of one of the parental nuclei. 

Plant cell culture techniques have provided the tools to enable successful recovery of chloroplast recombinants. These include utilization of selectable chloroplast markers such as resistance to the emtibiotics streptomycin and lincomycln (10) and efficient methods for somatic cell fusion that enable the production of large numbers of cells with mixed chloroplast populations (33). 

As late as 1984, scientists David McGrath and Davor Solter wrote in the journal Science, The cloning of mammals by simple nuclear transfer is biologically impossible. That assertion has been proven false, and since that date sheep, mice, cows, monkeys—a virtual menagerie of mammals—have been cloned. A moratorium on the cloning of humans has been enforced by law and by intimidation. Yet the announcement of the first true human clone— from somatic cell and egg cell fusion to embryonic birth—is only a question of time. Whether it occurs in a federal laboratory or in a private clinic, it will happen. 

Somatic cell hybrid The cell resulting from the fusion of animal cells derived from somatic cells that differ genetically. 

Telomeres are nucleoprotein structures located at the ends of eucaryotic chromosomes. They protect chromosome ends from fusion and degradation and ensure complete replication of chromosomal DNA. In human somatic cells, telomeres have 1.000 to 3,000 repeats. They gradually shorten with every cell division. This shortening i.s thought to limit their proliferative capacity. Cancer cells, in contrast, can maintain their telomere length and thus become immortalized. They do this by reactivating telomerase, a specific reverse transcriptase with an endogenous RNA template. ... 

One approach to overcome the transplant rejection of human embryonic stem (ES) cells is to derive them by nuclear transfer of the patients own cells. In the absence of an efficient protocol for human somatic cell nuclear transfer (SCNT), several critical steps must be optimized, namely reprogramming time, activation method, and in vitro culture conditions. Reprogramming time was defined as the time between cell fusion and oocyte activation to permit proper embryonic development. A 2 h reprogramming time led to 25% of the recon-stracted embryos developing to blastocysts. In SCNT, in the absence of sperm-mediated activation, an artificial stimulus is needed to initiate embryo development. Addition of 10 pM ionophore for 5 min, and incubation with 2.0 mM 6-dimethyl aminopurine for 4 h, was the most efficient chemical activation protocol for human SCNT embryos. Encouragingly, inefficiencies in embryo culture have been overcome by supplementing... 

Since there is an absence of reports detailing the activation of human SCNT oocytes and the successful production of cloned blastocysts, it was necessary to identify several parameters, including the reprogramming time (the time between cell fusion and egg activation, returning the gene expression profile of the somatic cell to that needed for appropriate embryonic development) and activation methods. Based on results from animal SCNT oocytes and the parthenogenetic activation of human oocytes, we initially employed a porcine activation protocol (simultaneous fusion and activation with electrical pulse) which used hu-... 

Hwang Enudeation.mpeg Human somatic cell nuclear transfer (SCNT) enucleation, injection of donor cell and fusion donor cell and oocyte. (kindly provided by Woo Suk Hwang, Seoul National University)... 

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