Fungal Cells

 1. Yeast:- Yeast is an unicellular eukaryotic fungus containing a small well characterized genome. Unlike plant or animal cells, it has rather fast growth rate and itself is a non-pathogenic fungus. Most of its gene contain introns which are spliced during purification of mature mRNA. It appears that intron found in yeast contain sequences for correct splicing as they are totally absent in higher eukaryotes. Moreover, yeast can carry out post-translational modification such as removal of signal sequence from a precursor polypeptide after the secretion of cell. This reveals a major advantage of yeasts over the bacteria. Success in DNA cloning in yeast depends on uptake of foreign DNA by its spheroplast in the presence of calcium ion and polyethyleneglycol (PEG). The spheroplasts develop cell wall after the incorporation of DNA.