Fig. 7
Characterization of green algal DUO1 orthologs. a Expression profiles of DUO1 orthologs from three Chara species, C. braunii (Cbr), C. australis (Cau), and C. leptospora (Cle) representing two distant clades (subgenera)41. Ribosomal protein L6 (RPL6) was used as the internal control. The expression of two flagella component genes (RSP11 and PACRG) was also analyzed in C. braunii. CbrDUO1 gene structure and amplified probed regions are shown in Supplementary Figure 7a. The whole untrimmed images are shown in Supplementary Figure 7b. Oogonia contain the egg. Antheridia contain developing sperm. Thalli are somatic vegetative tissue. b Position weight matrix representations of the top-scoring 8-mer DNA sequences bound by different MYB domains on a protein-binding DNA microarray. CpeDUO1 is DUO1 from Closterium peracerosum-strigosum-littorale complex (conjugating green alga). Numbers denoted on the right side of each motif represent the motif E- and Z-scores19. c In vivo transcriptional activation potentials of green algal DUO1 chimeras. DUO1 transcriptional activation potentials were measured by relative luciferase activity (right) (n = 4; **p < 0.01; ns, not significant; Student’s t-test). Schematic diagrams of constructs are color-coded light blue (AtDUO1), dark blue (MpDUO1), green (CbrDUO1), and purple (CpeDUO1). d The morphology of mature sperm of Mpduo1-1ko complemented by the expression of WT MpDUO1 (top), AtDUO1-MYB domain with MpDUO1 C-terminus chimera (middle), and CbrDUO1-MYB domain with MpDUO1 C-terminus chimera (bottom). The blue signals indicate the DAPI stained nuclei. Constructs are color-coded as in c. e Expression profiles of CpeDUO1 and sexual reproduction-specific CpeRLK1 and CpePI in Closterium peracerosum-strigosum-littorale complex. Stages equivalent to gametes in anisogamous plants are highlighted in blue. Relative expression ([reads per total sequenced reads] × 1,000,000) was used
