Mapping of CRC and TSL expression in gynoecium tissues onto the phylogenetic tree of the angiosperms. The Amborella and Cabomba (Nymphaeales) lineages are placed in equally basal positions to reflect uncertainty in their order of branching (2).

Comparisons of predicted protein domains in CRC and AmbCRC (A) and TSL and CabTSL (B). CC, coiled-coil domain; CAT, protein kinase catalytic domain; NLS, nuclear localization signal; Q, glutamine-rich region; Y, YABBY (DNA-binding) domain; Zf, zinc-finger domain.

Phylogenetic analysis of AmbCRC with other predicted YABBY proteins. The tree shown was constructed by the neighbor joining method (37) from an alignment corresponding to amino acid residues 19–55 (the zinc-finger domain) and 110–157 (the YABBY domain) of Arabidopsis CRC. Arabidopsis sequences are underlined, and percentage support for nodes in 500 bootstrap replicates are encircled. Unpublished sequence accession numbers are as follows: AY451399 (Antirrhinum), AY703987 (Lepidium), AY071845 (Nicotiana), and AF545436 (wheat).

Northern and virtual Northern blot hybridizations of AmbCRC, CabTSL, and their Arabidopsis orthologues. Hybridizations are to virtual Northern blots of A. trichopoda and polyadenylated RNA Northern blots of C. aquatica and A. thaliana. Hybridizations to a cDNA encoding GAPDH from each species are included to demonstrate equivalent loading of tracks. F, female flowers; I, inflorescences; L, leaves; M, male flowers; RL, rosette leaves; and V, vegetative tissues (submerged leaves and stems).

Nonradioactive in situ hybridizations showing expression of AmbCRC in A. trichopoda and CabTSL in C. aquatica, with accompanying images. In situ hybridization signals appear blue or violet. Very dark material in tepals of A. trichopoda is natural coloration. All gene expression signals referred to were specific to antisense-strand riboprobes and were not observed by using negative control sense-strand riboprobes on serial sections from the same tissue blocks (results not presented). (A) A female flower of A. trichopoda. (B) In situ hybridization to a longitudinal section (l.s.) of an A. trichopoda female flower bud showing AmbCRC expression in the carpel wall. (C) SEM of a female A. trichopoda flower bud with the perianth removed (stage as for B). (D) SEM of a mature A. trichopoda female flower. (E) In situ hybridization to an l.s. of an A. trichopoda male flower bud showing AmbCRC expression in the stamen filaments. (F) In situ hybridization to an l.s. of a C. aquatica flower bud showing expression of CabTSL in the style and stigma. (G) SEM of the C. aquatica gynoecium (stage as for F). (H) In situ hybridization to a transverse section (t.s.) of a 3-mm-long C. aquatica flower bud showing expression of CabTSL in the style and stigma. (I) In situ hybridization to an l.s. of a 4-mm-long C. aquatica flower bud showing expression of CabTSL in the stigma. (J) SEM of the stigma and upper style of C. aquatica (stage as for I). (K) In situ hybridization to a t.s. of a C. aquatica flower bud showing expression of CabTSL in the anther wall. (L) SEM of a C. aquatica flower bud showing the stamens (stage as for K). (M) A flower and dimorphic leaves of C. aquatica.(N) In situ hybridization to a t.s. of a C. aquatica flower peduncle showing expression of CabTSL in cells surrounding air canals. (O) In situ hybridization to an l.s. of a C. aquatica floating leaf showing expression of CabTSL in cells surrounding air canals in the petiole. a, anther; ac, air canal; al, anther loculus; c, carpel; d, dehiscence zone; f, stamen filament; fb, floating leaf blade; o, ovary; ov, ovule; p, perianth; pd, peduncle; pe, petiole; r, receptacle; sc, stylar canal; sm, staminode; st, stigma; su, submerged leaves; sy, style; t, tepal.