| Title: | A mating-type mutagenesis screen identifies a zinc-finger protein required for specific DNA excision events in Paramecium |
| Author(s): | Bhullar S; Denby Wilkes C; Arnaiz O; Nowacki M; Sperling L; Meyer E; |
| Address: | "IBENS, Ecole Normale Superieure, CNRS, Inserm, PSL University, F-75005 Paris, France. Institute of Cell Biology, University of Bern, 3012 Bern, Switzerland. Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Universite Paris-Saclay, 91198 Gif-sur-Yvette cedex, France" |
| ISSN/ISBN: | 1362-4962 (Electronic) 0305-1048 (Print) 0305-1048 (Linking) |
| Abstract: | "In the ciliate Paramecium tetraurelia, functional genes are reconstituted during development of the somatic macronucleus through the precise excision of approximately 45 000 single-copy Internal Eliminated Sequences (IESs), thought to be the degenerate remnants of ancient transposon insertions. Like introns, IESs are marked only by a weak consensus at their ends. How such a diverse set of sequences is faithfully recognized and precisely excised remains unclear: specialized small RNAs have been implicated, but in their absence up to approximately 60% of IESs are still correctly excised. To get further insight, we designed a mutagenesis screen based on the hypersensitivity of a specific excision event in the mtA gene, which determines mating types. Unlike most IES-containing genes, the active form of mtA is the unexcised one, allowing the recovery of hypomorphic alleles of essential IES recognition/excision factors. Such is the case of one mutation recovered in the Piwi gene PTIWI09, a key player in small RNA-mediated IES recognition. Another mutation identified a novel protein with a C2H2 zinc finger, mtGa, which is required for excision of a small subset of IESs characterized by enrichment in a 5-bp motif. The unexpected implication of a sequence-specific factor establishes a new paradigm for IES recognition and/or excision" |
| Keywords: | "Alleles DNA Repair/*genetics DNA Transposable Elements/genetics DNA, Protozoan/genetics Gene Rearrangement/genetics Introns/genetics Macronucleus/genetics/physiology Mating Factor/*genetics Mutagenesis/*genetics Paramecium tetraurelia/genetics/physiology;" |
| Notes: | "MedlineBhullar, Simran Denby Wilkes, Cyril Arnaiz, Olivier Nowacki, Mariusz Sperling, Linda Meyer, Eric eng 260358/ERC_/European Research Council/International 681178/ERC_/European Research Council/International Research Support, Non-U.S. Gov't England 2018/08/31 Nucleic Acids Res. 2018 Oct 12; 46(18):9550-9562. doi: 10.1093/nar/gky772" |
