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The Ate1 arginyltransferase (R transferase) is a component of the N-end rule pathway, which recognizes proteins containing N-terminal degradation signals called N-degrons, polyubiquitylates these proteins and thereby causes their degradation by the proteasome. Ate1 arginylates N-terminal Asp, Glu or (oxidized) Cys. The resulting N-terminal Arg is recognized by ubiquitin ligases of the N-end rule pathway. In the yeast Saccharomyces cerevisiae, the separase-mediated cleavage of the Scc1/Rad21/Mcd1 cohesin subunit generates a C-terminal fragment that bears N terminal Arg and is destroyed by the N-end end rule pathway without requirement for arginylation. In contrast, the separase-mediated cleavage of Rec8, the mammalian meiotic cohesin subunit, yields a fragment bearing N terminal Glu, a substrate of the Ate1 R transferase. Here we constructed and used a germ cells confined Ate1-/- mouse strain to analyze the separase-generated C-terminal fragment of Rec8. We show that this fragment is a short-lived N-end rule substrate, that its degradation requires N terminal arginylation, and that male Ate1-/- mice are nearly infertile, owing to massive apoptotic death of Ate1-/- spermatocytes during the metaphase of meiosis I. These effects of Ate1 ablation are inferred to be caused, at least in part, by the failure to destroy the C-terminal fragment of Rec8 in the absence of N-terminal arginylation. [ABSTRACT FROM AUTHOR]