Mammalian Cells With Half The Number Of Chromosomes

Haploid cells are a powerful genetic tool to analyse gene function. In the past decade, a number of researchers finally succeeded in developing haploid cell line cultures. With the exception of sperm and egg cells, human cells have two sets of chromosomes, one inherited from each parent.

Organisms with only one set of chromosomes, however, can be extremely useful for scientific research. Cells with a single set of chromosomes are a powerful tool to study gene functions; because you can modify just one copy of the gene to analyse its effects on the organism. Haploid cells in microorganisms such as yeasts have been extensively using for gaining powerful insights that have revolutionising the history of biomedicine.

Cells with chromosomes

Since mammalian haploid cell cultures were not available until recently; researchers have used other tools to conduct genetic screens, such as interfering RNA. However, these alternative strategies have non-specific effects that are inconvenient for any genetic approach.

Yeasts were using, for instance, by the 2001 Nobel Laureates in Physiology to identifying key molecules that regulating the cell cycle in eukaryotic organisms. However, yeasts and humans are separating by a billion years of evolution; and many biological mechanisms have not been retaining; which means they cannot be studying in these microorganisms.

First, a near-haploid cell line was obtaining from a leukemia patient; years later, methods were developing to establish embryonic haploid stem cell lines from a number of mammals; including humans. However, all these animal haploid cell cultures are highly unstable and become diploid quickly.

Animal haploid cells

The study finding that haploid cells activate mechanisms of cell death via the p53 protein; as a result, haploid cells are no longer viable in culture and progressively disappear. These results explained why it is so difficult to maintain animal haploid cells in the lab. This compound acts on microtubules, factors involved in the migration of chromosomes during cell division.

The study revealed that a precursor in the synthesis of the anticancer agent Taxol named DAB (10-Deacetylbacattin III) allows haploid cells to grow better and replace diploid cells in cultures. This effect is not limited to haploid cells, since tetraploid cells (cells with four sets of chromosomes) exposing to DAB are also more significantly affected than diploid cells.

In other words, this strategy allows researchers to generically select for cells with a lower number of chromosomes in mixed cultures of mammalian cells. The results of this study might help identify cancer patients that might preferentially benefit from a treatment using taxol or other taxane derivatives.