Contact information
Ching-Ming Cheng, Associate Prof.
Department of Life Sciences
Tel: 886-3-8565301 ext.2614/2615
e-mail: lschingming@mail.tcu.edu.tw
Lab Web Address: http://www.tculs.tcu.edu.tw/?page_id=841
Research expertise
Plant molecular breeding, Biotechnology
Research Interest
- A yeast functional expression system for positive selection of plant triterpene cyclyase Genetic engineering of plant secondary metabolites in Saccharomyces cerevisiae could be used to produce large amounts of desired metabolites that are either difficult to be extracted from the natural sources, or too expensive and complex to be produced by chemical synthesis. As the first step towards the production of usable pharmaceuticals in yeast, we have constructed a yeast positive selection system for direct isolation of novel terpenoid cyclyase from plants, especially from traditional Chinese herbal plants without detailed genetic or molecular information. A diploid yeast was mutated by homologous recombination to replace one copy of the erg7 gene that encodes the yeast lanosterol synthase responsible for the cyclization of 2,3-oxidosqualene. The heterozygotic mutants were selected and transformed with a recombinant copy of erg 7 using the URA3 containing centromeric plasmid pRS416-erg7. The transformants were sporulated to obtain haploid yeasts transformed with plant cDNA libraries. The URA3 on plasmid pRS416-erg7 will arrested the growth of the yeast transformants platting with 5-fluoroorotic acid (5-FOA). Only if the haploid yeasts exclude the plasmid pRS416-erg7and a plant cDNA that complements the defect of 2,3-oxidosqualene cyclization will the yeast cells get survivor. In this way, we could screen the cDNA libraries of Chinese herbal plants to isolate novel plant terpenoid synthase in a one-step positive screening network.
- The primary immunity determinant in modulating the lysogenic immunity of the filamentous bacteriophage cf.
To understand the immunity determinants of bacteriophage cf, we applied DNA shuffling to generate cf immunity mutants. An immunity mutant cf-ls (m-3-IG) was obtained with an infection efficiency of 106-109 fold greater than the wild type cf. Sequence comparison revealed one base increase and eight single nucleotide polymorphisms (SNPs). The nine mutations was sub-cloned to construct the cf-ls-P and cf-ls-R phages carrying the four mutations on the hypothetical PT repressor and the other five mutations upstream of the PT coding region, respectively. Phage cf-ls-P expressed an unexpected low superinfection efficiency as the wild type cf and phage cf-ls-R has completely lost its superinfection ability to the cf-lysogen. This has suggested the PT inhibitor protein and the non-coding upstream region which mediates an RNA-RNA interaction, are both involved in the regulatory mechanism of cf immunity. The result is accordance with our previous study by Cheng et al. (1999).
Selected Publication
- Cheng, C. M., Pelle Stolt. 2014. Basic and Applied Research on Boehmeria (Ramie) Utilising CAPS Marker Technology. Cleaved Amplified Polymorphic Sequences (CAPS) Markers in Plant Biology 11, 167-181.
- CI Li, SJ Chiou, TS Tong, CY Lee, LT Lee and M. Cheng. 2010. Development and validation of molecular markers for characterization of Boehmeria nivea var. nivea and Boehmeria nivea var. tenacissima. Chinese Medicine 2010, 5:40
- Lahmy, , J. Guilleminot, C. M. Cheng, N. Bechtold,†, S. Albert, G. Pelletier, M. Delseny and M. Devic. 2004. DOMINO1, a member of a small plant-specific gene family encodes a protein essential for nuclear and nucleolar functions. The Plant Jounal 39, 809-820.
- Cheng, C. M., A. Palloix and V. Lefebvre. 2002. Isolation, mapping and characterization of allelic polymorphism of Chi-PM1, a class III chitinase of Capsicum annuum Plant Science 163, 481-489.
- Cheng, C. M., J. Wang, H. J. Bau and T. T. Kuo. 1999. The primary immunity determinant in modulating the lysogenic immunity of the filamentous bacteriophage cf. J. Mol. Biol. 287, 867-876.