Decoding a Noncanonical Splicing Code in Euglena

— A new rulebook for eukaryotic gene expression revealed in PNAS — A joint research team from RIKEN, Yamagata University, the University of Tokyo, Euglena Co., Ltd., Kochi University, Tsuruoka College, and collaborators has uncovered that Euglena employs a widespread, nonconventional intron system alongside the textbook GT–AG rule of eukaryotic RNA splicing. Through genome-wide analysis and precise genome editing assays, the team decoded the DNA sequence signature that enables this unusual form of splicing—and showed it can be programmed with fully synthetic introns. Why it matters In most eukaryot