Figure 1.

miRNAs Can Quantitatively Regulate Multiple Transcripts Simultaneously and Phenocopy Their Combined Loss of Function.

(A) A scheme of an endogenous pre-miRNA. The red and blue fragments will be cleaved by DICER-LIKE1 (DCL1) to generate the miRNA and miRNA*, respectively.

(B) A 10-d-old wild-type seedling.

(C) The promoter of PHB drives GFP expression throughout the shoot apex in wild-type heart-stage embryos.

(D) Arabidopsis cuc1 cuc2 double mutant seedlings.

(E) F1 seedlings of OP:miR164b transactivated by PHB:LhG4.

(F) A monocot-like phv phb rev triple mutant seedling.

(G) A monocot-like PHB≫miR165b seedling of comparable age.

(H) Whole shoot and flower (inset) of 35S:miR167a plant next to same age wild type display identical alterations found in arf6 arf8 double mutants (cf. with Nagpal et al., 2005).

(I) Scanning electron micrograph of wild-type flowering apex.

(J) A cross section through AP1≫HP-GFP flowering apex with expression throughout emerging flower meristems.

(K) Wild-type flower.

(L) Fused sepals and absent petals in AP1≫miR164b flower.

(M) Flowering apex and filamentous flowers (inset) of strong AP1≫miR165b plant.

(N) Normal sepals, radial petals, distorted stamens, and multiple carpels in a weak AP1≫miR165b flower.

(O) Sequence alignment of the wild type and phv-1d mutant with corresponding miR165b and miR165bm6.

(P) Seedling expressing ANT≫miR165b#4 results in radialized cotyledons and aborted meristem.

(Q) and (R) Adaxial surface of wild-type (Q) and ANT≫miR165bm6 (R) leaves. Note the adaxial outgrowths of the transgenic leaf (arrow).

(S) Normal sepals, distorted stamens, and multiple carpels in a strong ANT≫miR165bm6 flower.

FM, flower meristem; IM, inflorescence meristem; P, petal. Bars = 3 mm in (B), (F), and (G) and 20 μm in (C), (I), and (J).