Arabidopsis DOK1 encodes a functional dolichol kinase involved in reproduction

Abstract

SUMMARYDolichol phosphate (Dol-P) serves as a carrier of complex polysaccharides during protein glycosylation. Dol-P is synthesized by the phosphorylation of dolichol or the monodephosphorylation of dolichol pyrophosphate (Dol-PP); however, the enzymes that catalyze these reactions remain unidentified in Arabidopsis thaliana. We performed a genome-wide search for cytidylyltransferase motif-containing proteins in Arabidopsis, and found that At3g45040 encodes a protein homologous with Sec59p, a dolichol kinase (DOK) in Saccharomyces cerevisiae. At3g45040, designated AtDOK1, complemented defects in the growth and N-linked glycosylation of the S. cerevisiae sec59 mutant, suggesting that AtDOK1 encodes a functional DOK. To characterize the physiological roles of AtDOK1 in planta, we isolated two independent lines of T-DNAtagged AtDOK1 mutants, dok1-1 and dok1-2. The heterozygous plants showed developmental defects in male and female gametophytes, including an aberrant pollen structure, low pollen viability, and short siliques. Additionally, the mutations had incomplete penetrance. These results suggest that AtDOK1 is a functional DOK required for reproductive processes in Arabidopsis.

Global DNA methylation variations after short-term heat shock treatment in cultured microspores of Brassica napus cv. Topas

“…In addition, BnaC01g24140D was similar to AtDOK1 (A. thaliana dolichol kinase 1 ), the expression of which could complement the temperature-sensitive growth and glycosylation defects of the Saccharomyces cerevisiaesec59 mutant30. Moreover, AtDOK1 is involved in the synthesis of dolichol phosphate (Dol-P), which serves as a carrier of complex polysaccharides during protein glycosylation30. Glycoproteins are confirmed to be involved in adaptation to biotic and abiotic stresses31.…”

“…The CHG DRG BnaA06g03030D resembled a heat stress-responsive gene FUT12 (fucosyltransferase 12 )29. In addition, BnaC01g24140D was similar to AtDOK1 (A. thaliana dolichol kinase 1 ), the expression of which could complement the temperature-sensitive growth and glycosylation defects of the Saccharomyces cerevisiaesec59 mutant30. Moreover, AtDOK1 is involved in the synthesis of dolichol phosphate (Dol-P), which serves as a carrier of complex polysaccharides during protein glycosylation30.…”

TURAN and EVAN Mediate Pollen Tube Reception in Arabidopsis Synergids through Protein Glycosylation

“…Applying SRM to tun-1/TUN mutants revealed a stop codon in the sixth exon of At1g16570 ( Fig 2F ) [ 28 ], which encodes a putative UDP-glycosyltransferase superfamily protein belonging to the glycosyltransferase (GT) family 33, whereof TUN is the only member in Arabidopsis . In evn-1/EVN mutants, SRM identified a stop codon in the eleventh exon of At3g45040 ( Fig 2F and S6 Fig and S1 Table ), which encodes the only dolichol kinase in the Arabidopsis genome [ 29 ]. Thus, both TUN and EVN encode proteins that are likely playing roles in protein N-glycosylation.…”

“…As described previously, the T-DNA allele tun-2 (SAIL_400_A01) has an insertion in the fourth exon of At1g16570 and displays a PT overgrowth phenotype (15%; n = 513; Fig 2F and Table 1 and S1B Fig ) [ 28 ] and PT bursting in vitro (44% ± 6.5%; n = 404; Table 1 and S1F Fig ) similar to the EMS allele tun-1 , confirming the correct identification of TUN by SRM. Likewise, evn-3 (SAIL_529_E06) has an insertion in the eighth exon of At3g45040 and shows the same female (28%; n = 337) and male (50% ± 0%; n = 495) [ 29 ] phenotypes as the EMS mutants evn-1 and evn-2 ( Fig 2G and Table 1 and S1D Fig and S1H Fig ).…”

POLYPRENOL REDUCTASE2 Deficiency Is Lethal in Arabidopsis Due to Male Sterility

“…Indeed, developmental defects in male and female gametophytes leading to sterility similar to those observed for PPRD2 disruption have been reported for several null mutants, both upstream and downstream of Dol (Supplemental Table 6), e.g., for DOK deficiency (Kanehara et al, 2015).…”