The double-stranded DNA-binding proteins TEBP-1 and TEBP-2 form a telomeric complex with POT-1
Sabrina Dietz, Miguel Vasconcelos Almeida, Emily Nischwitz, Jan Schreier, Nikenza Viceconte, Albert Fradera-Sola, Christian Renz, Alejandro Ceron‐Noriega, Helle D. Ulrich, Dennis Kappei, René F. Ketting, Falk Butter
Abstract
Telomeres are bound by dedicated proteins, which protect them from DNA damage and regulate telomere length homeostasis. In the nematode Caenorhabditis elegans, a comprehensive understanding of the proteins interacting with the telomere sequence is lacking. Here, we harnessed a quantitative proteomics approach to identify TEBP-1 and TEBP-2, two paralogs expressed in the germline and embryogenesis that associate to telomeres in vitro and in vivo. tebp-1 and tebp-2 mutants display strikingly distinct phenotypes: tebp-1 mutants have longer telomeres than wild-type animals, while tebp-2 mutants display shorter telomeres and a Mortal Germline. Notably, tebp-1;tebp-2 double mutant animals have synthetic sterility, with germlines showing signs of severe mitotic and meiotic arrest. Furthermore, we show that POT-1 forms a telomeric complex with TEBP-1 and TEBP-2, which bridges TEBP-1/-2 with POT-2/MRT-1. These results provide insights into the composition and organization of a telomeric protein complex in C. elegans.