Many fascinating biological phenomena, of which we currently have little to no molecular understanding, can be observed in the tiny marine bristle worm Platynereis dumerilii. It displays a slow rate of evolution, which permits analyses of ancestral genes and cell types, possesses a vertebrate-type hormonal system, as well as the ability to regenerate large pieces of its body. Furthermore, its reproductive timing is controlled by multiple timers – a feature likely to be common to many other organisms. These characteristics make it an ideal model for evolutionary studies as well as for chronobiology, amongst other research fields. However, dissecting Platynereis gene function in vivo had remained challenging due to a lack of available tools.
TALENs as a new tool to engineer targeted modifications in Platynereis genes
To address this need, scientists from the Max F. Perutz Laboratories (MFPL) and the Research Platform "Marine Rhythms of Life" of the University of Vienna and supported by the VIPS (Vienna International Postdoctoral program) have now established customized transcriptional activator-like effector nucleases (TALENs) as a tool to engineer targeted modifications in Platynereis genes. These tailored enzymes bind specific DNA sequences and "cut" the genome at these locations. The repair mechanisms of the cell promptly repair the damage, however small errors in the form of insertions and deletions can be introduced during the repair process. The result is the generation of small mutations that render the protein product of the gene non-functional – allowing the generation of the first-ever Platynereis mutants.
The researchers found out that the induced mutations are heritable, demonstrating that TALENs can be used for generating mutant lines in this bristle worm. "This new tool opens the door for detailed in vivo functional analyses in Platynereis and can also facilitate further technical developments. For example, we hope to use TALENs to insert fluorescent reporter genes into the genome. In this way we can study how gene expression is regulated across the entire lifecycle", explains first author Stephanie Bannister, VIPS Postdoc in Florian Raible’s group at the Department of Microbiology, Immunobiology and Genetics at the University of Vienna. She spearheaded the establishment of the technique. "In addition, we have provided a streamlined workflow that can serve as a template for the establishment of TALEN technology in other non-conventional and emerging model organisms", Stephanie Bannister adds.
Original publications in Genetics:
Stephanie Bannister, Olga Antonova, Alessandra Polo, Claudia Lohs, Natalia Hallay, Agne Valinciute, Florian Raible, Kristin Tessmar-Raible: TALENs mediate efficient and heritable mutation of endogenous genes in the marine annelid Platynereis dumerilii. In: Genetics (March 2014). DOI: dx.doi.org/10.1534/genetics.113.161091
Juliane Zantke, Stephanie Bannister, Vinoth Babu Veedin Rajan, Florian Raible, Kristin Tessmar-Raible: Genetic and genomic tools for the marine annelid Platynereis dumerilii. In: Genetics (May 2014) DOI: dx.doi.org/10.1534/genetics.112.148254