engleski

The Arabidopsis SMG7/EST1-like protein is required for exit from meiosis

Meiosis consists of two nuclear divisions, which are separated by a short interkinesis. Here we report that the SMG7 protein plays an evolutionary conserved role in nonsense-mediated RNA decay (NMD) in animals and yeast is essential for the progression from anaphase to telophase in the second meiotic division in Arabidopsis. Arabidopsis SMG7 is an essential gene, disruption of which causes embryonic lethality. Plants carrying a hypomorphic smg7 mutation exhibit an elevated level of transcripts containing premature stop codons. This suggests that the role of SMG7 in NMD is conserved in plants. Furthermore, hypomorphic smg7 alleles render mutant plants sterile by causing an unusual cell cycle arrest in anaphase II that is characterized by delayed chromosome decondensation and aberrant rearrangement of the meiotic spindle. The smg7 phenotype was mimicked by exposing meiocytes to the proteasome inhibitor MG115. Together, these data indicate that SMG7 counteracts CDK activity at the end of meiosis, and reveal a novel link between SMG7 and meiotic cell cycle regulation

anaphase promoting complex (APC); CDK; mitosis

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