Targeting secondary metabolite biosynthetic genes from the metagenome of the sponge Mycale sp

• Published in: Planta Medica
• Main Authors: Van der Sar, SA, Fisch, KM, Gurgui, C, Nguyen, TA, Piel, J, Webb, V
• Format: Conference Proceeding
• Language: English
• Published: 04.08.2008
• ISSN: 0032-0943; 1439-0221
• DOI: 10.1055/s-0028-1084798

Many natural products from marine sponges have been suspected to be produced by symbiotic bacteria. Their cultivation usually fails, thus making their direct study and exploitation for sustainable drug production difficult. One approach in overcoming this problem is to identify and express biosynthetic gene clusters from the metagenomic DNA of these sponges. A substantial body of evidence has already been gathered, indicating the bacterial origin of a number of members from the pederin family of natural products, using these genetic methods [1]. Mycalamide A, a member of the pederin family, peloruside A, a macrolide related to the bryostatins and pateamine A, a macrolide recently shown to have potential as an anticancer drug [2], are natural products that have been isolated from the New Zealand marine sponge, Mycale sp., but are suspected to be produced by symbiotic bacteria living within the sponge. The vast genomic and metabolic complexity of bacteriosponges, however, requires new laboratory protocols to be developed. Specifically, the poor quality of total DNA isolated from sponges according to standard procedures, the difficulty to identify genes of interest among numerous homologs, and the time-consuming screening procedures to identify and isolate the rare positive clones, have all been addressed. In addition to the improvement of strategies for the construction of metagenomic libraries, used for the study of sponge polyketide biosynthesis, a new approach to screening [3] has allowed a program to be developed that allows us to probe the Mycale sp. metagenome for the desired PKS gene clusters. Using these methods, amplification of several DNA fragments has provided several trans-AT PKS sequences belonging to mycalamide A and pateamine A gene clusters. The discussion of the ongoing work on the mycalamide A, peloruside A, and pateamine A biosynthetic gene clusters, highlights opportunities and technical challenges of current sponge metagenomics. References1. Piel, J. et al. (2005)J. Nat. Prod. 68:472–479. 2. Low, W-K. et al. (2005) Mol. Cell 20:709–722. 3. Nguyen, TA. et al. (2008) Nat. Biotechnol. 26:225–233