title: TheArabidopsisNMD Factor UPF3 Is Feedback-Regulated at Multiple Levels and Plays a Role in Plant Response to Salt Stress.
abstract: Nonsense-mediated mRNA decay (NMD) is a eukaryotic RNA surveillance mechanism that degrades aberrant transcripts and controls the levels of many normal mRNAs. It was shown that balanced expression of the NMD factor UPF3 is essential for the maintenance of proper NMD homeostasis inArabidopsis.UPF3expression is controlled by a negative feedback loop that exposesUPF3transcript to NMD. It was shown that the long 3' untranslated region (3' UTR) ofUPF3exposes its transcript to NMD. Long 3' UTRs that subject their transcripts to NMD were identified in several eukaryotic NMD factors. Interestingly, we show here that a construct that contains all the regulatory regions of theUPF3gene except this long 3' UTR is also feedback-regulated by NMD. This indicates thatUPF3expression is feedback-regulated at multiple levels.UPF3is constitutively expressed in different plant tissues, and its expression is equal in leaves of plants of different ages. This finding is in agreement with the possibility that UPF3 is ubiquitously operative in theArabidopsisNMD pathway. Expression mediated by the regulatory regions ofUPF3is significantly induced by salt stress. We found that both a deficiency and a strong excess ofUPF3expression are detrimental to plant resistance to salt stress. This indicates thatUPF3plays a role in plant response to salt stress, and that balanced expression of theUPF3gene is essential for coping with this stress.
authors.affiliation: The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University Ramat-Gan, Israel.
authors.forename: Karina
authors.initials: K
authors.lastname: Vexler
authors.affiliation: The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University Ramat-Gan, Israel.
authors.forename: Miryam A
authors.initials: MA
authors.lastname: Cymerman
authors.affiliation: The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University Ramat-Gan, Israel.
authors.forename: Irina
authors.initials: I
authors.lastname: Berezin
authors.affiliation: The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University Ramat-Gan, Israel.
authors.forename: Adi
authors.initials: A
authors.lastname: Fridman
authors.affiliation: The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University Ramat-Gan, Israel.
authors.forename: Linoy
authors.initials: L
authors.lastname: Golani
authors.affiliation: The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University Ramat-Gan, Israel.
authors.forename: Michal
authors.initials: M
authors.lastname: Lasnoy
authors.affiliation: The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University Ramat-Gan, Israel.
authors.forename: Helen
authors.initials: H
authors.lastname: Saul
authors.affiliation: The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University Ramat-Gan, Israel.
authors.forename: Orit
authors.initials: O
authors.lastname: Shaul
keywords: IME; NMD regulation; NaCl; RNA stability; intron-mediated enhancement; negative feedback loop; nonsense-mediated mRNA decay; salt stress