Other Yeast Species  [2]

Transformation protocols have been developed for numerous other species of yeast of genetic or commercial importance. The following list is not exhaustive but will give readers a starting place to identify protocols for their specific needs.

 

Schizosaccharomyces pombe

Shortly after the discovery of spheroplast transformation in S. cerevisiae, this technique was applied to S. pombe. A protocol for this method is given by Moreno et al. Variants of this technique can be found on both the Forsberg laboratory website (pingu.salk.edu/~forsberg / tfmn.html) and the Fission Yeast Handbook from the Nurse Laboratory (www.bio.uva.nl/pombe/handbook/section2/section2-2.html).  

Candida albicans

The transformation of this yeast can be accomplished using the LiAc or electroporation methods.

Pichia pastoris

This methylotrophic yeast is currently being used to produce recombinant proteins. Specific expression vectors, containing the methanol responsive promoter of the alcohol oxidase gene, give very high levels of recombinant proteins. Both the spheroplasting and electroporation methods can be used to transform this species.

More

The spheroplast, lithium cation, and electroporation transformation methods have been successfully applied to a number of different yeast species . These include Hansenula polymorpha, Klyveromyces spp, Yamadazyma ohmeri, Yarrowia lipolytica, and Schwanniomyces occidentalis.

 

 

Future Research

1. Visualization of the transformation process of S. cerevisiae by using both electron microscopy and labelled DNA [25].

 

2. Quantitative analysis of the transformation of S. cerevisiae is required. For example, in mammalian cells, successful transfection can be quantitatively evaluated by fluorescent-activated cell sorting or by the expression of a reporter gene [26]. In contrast, successful transformation of S. cerevisiae can be monitored only by counting the number of transformants and viable cells, which requires 3–4 days and is less quantitative than the methods used for the mammalian system.

 

3. Transformation of S. cerevisiae and other fungi is indispensable for manipulating these organisms. However, the mechanism underlying the transformation is still unknown. S. cerevisiae has many advantages as a model organism and can be used to understand the transformation mechanism. Elucidation of the mechanism will contribute to increasing the transformation efficiency of fungi and clarifying the mechanism underlying mammalian transfection [25].