Yang Bi, Zhiping Deng, Weimin Ni, Ruben Shrestha, Dasha Savage, Thomas Hartwig, Sunita Patil,Su Hyun Hong, Zhenzhen Zhang, Juan A. Oses-Prieto, Kathy H. Li, Peter H. Quail,Alma L. Burlingame, Shou-Ling Xu, Zhi-Yong Wang.

Nature Communication; (2021)12:945 | https://doi.org/10.1038/s41467-021-20929

O-GlcNAc modification plays important roles in metabolic regulation of cellular status. Two homologs of O-GlcNAc transferase, SECRET AGENT (SEC) and SPINDLY (SPY), which have O-GlcNAc and O-fucosyl transferase activities, respectively, are essential in Arabidopsis but have largely unknown cellular targets. Here we show that AtACINUS is O-GlcNAcylated and O-fucosylated and mediates regulation of transcription, alternative splicing (AS), and developmental transitions. Knocking-out both AtACINUS and its distant paralog AtPININ causes severe growth defects including dwarfism, delayed seed germination and flowering, and abscisic acid (ABA) hypersensitivity. Transcriptomic and protein-DNA/RNA interaction analyses demonstrate that AtACINUS represses transcription of the flowering repressor FLC and mediates AS of ABH1 and HAB1, two negative regulators of ABA signaling. Proteomic analyses show AtACINUS’s O-GlcNAcylation, O-fucosylation, and association with splicing factors, chromatin remodelers, and transcriptional regulators. Some AtACINUS/AtPININdependent AS events are altered in the sec and spy mutants, demonstrating a function of Oglycosylation in regulating alternative RNA splicing.

See: https://www.nature.com/articles/s41467-021-20929-7.epdf?sharing_token=dGyir9sYCe1LmQEvTHTzJNRgN0jAjWel9jnR3ZoTv0NfocUseM-ERaZo8xk9MJWbOEkqBs8Rt6zLo8AGgHrN8OiEA-ZFLV2zMlbZ123Ao7HCxkG8JPboeKNI00BT1FYgD9jNTxOqvLN2tx6e25_IjOsDhfJ2G2fT1RwQRSrCJ1g%3D

Figure 1: AtACINUS and AtPININ are genetically redundant. a Diagrams of the domain structures of AtACINUS and AtPININ. SAP: SAF-A/B, Acinus, and PIAS motif. RRM: RNA-recognition motif. RSB: RNPS1–SAP18 binding domain. G and F indicates the position of O-GlcNAcylation and Ofucosylation modifications, respectively. b The sequence alignment of the RSB domains of AtACINUS and AtPININ. Conserved amino acids are highlighted in green. c Diagrams of the AtACINUS and AtPININ (translation start at position 1) with T-DNA insertion sites in acinus-1, acinus-2, and pinin-1 mutants. d Plant morphologies of wild-type (WT), acinus-1, acinus-2, pinin-1, acinus-1 pinin-1, and acinus-2 pinin-1 grown on soil for 20 days. e Fiveweek-old WT, acinus-1, acinus-2, pinin-1, acinus-1 pinin-1, and acinus-2 pinin-1 plants grown under long day condition. Inset shows enlarged view of the acinus-1 pinin-1 and acinus-2 pinin-1 mutants. f Expression of either AtACINUS-GFP or YFP-AtPININ suppresses the growth defects in acinus-2 pinin-1 double mutant (ap).