Figure 4.

Antisense Transcription Contributes to a Reduction of FLC Intron 1 Expression with Cell Size in Prevasculature Tissue

(A) Fluorescence localization of full-length sense intron 1 (red, top right) and antisense (COOLAIR) 5′ end distal intron (green, bottom right) and wider-field merge (left), all with DAPI stain (blue), in representative ColFRI prevasculature root cells, with the same cells in different images identified by ^∗ or ^∗∗, respectively. Scale bar, 5 μm. Also shown (top) is schematic of FLC gene with sense transcript as in Figure 2A, and antisense proximal and distal isoforms together with corresponding sense and antisense probe sets.

(B) Average cellular foci number of full-length FLC intron 1 and COOLAIR 5′ end distal intron in outer layer (black) and prevasculature cells (white), from one and three biological replicates, respectively. Error bars denote SEM. ^∗p < 0.05, ^∗∗∗∗p < 10⁻⁴.

(C) Area dependence of average cellular foci count per cell of full-length FLC intron 1 and COOLAIR 5′ end distal intron in ColFRI root outer layer cells (outer) and full-length FLC intron 1 in prevasculature (prevasc) root cells. Data as in (B) and Figure 2B. Error lines denote SEM as a function of area.

(D) As in (C), here for FLC and COOLAIR expression in prevasculature cells.

(E) Area dependence of average cellular foci counts per cell of full-length FLC intron 1 from terminator exchange (TEX) or wild-type FLC transgenes (CTL), in outer layer (outer) or prevasculature (prevasc) root cells, all from four biological replicates per condition. Error lines denote SEM as a function of area.

(F) As in (E), here for FLC and COOLAIR 5′ end distal intron expression in prevasculature cells.

(G) Schematic of FLC regulation by cell-size-dependent COOLAIR transcription in prevasculature cells.