%0 Journal Article %A Stephen E. Schauer %A Teresa A. Golden %A Delwin S. Merchant %A Biranchi Patra %A Jean D. Lang %A Sumita Ray %A Bulbul Chakravarti %A Deb Chakravarti %A Animesh Ray %T DCL1, a Protein that Produces Plant MicroRNA, Coordinates Meristem Activity %D 2013 %R 10.1101/001438 %J bioRxiv %P 001438 %X The ubiquity and importance of short duplex RNAs, termed microRNA (miRNA), for normal development in higher eukaryotes are becoming increasingly clear. We had previously shown that reduction-of-function mutations in Arabidopsis thaliana DCL1 (DICER-LIKE1) gene, affecting the nucleus-localized protein that produces 19-25 nucleotides long miRNA species from longer double stranded RNA precursors, cause a delay in flowering by prolonging the period of juvenile organ development. Here we show that DCL1 transcription is increased at the critical phase of juvenile to reproductive developmental transition, and that DCL1 protein is localized in meristematic cells of the shoot, inflorescence and flowering meristem. DCL1 protein is also expressed in the ovule funiculus, ovule integuments, and in early but not late embryo. Genetic analysis revealed that DCL1 exerts its effect along the same pathway that involves the floral pathway integrator gene LEAFY. Results are most consistent with the idea that DCL1 protein is required in the shoot apical meristem to prevent uncontrolled proliferation of meristematic cells. The expression of DCL1 protein in the early embryo may be either via the transmission of DCL1 mRNA through the female gametophyte, as suggested from the sporophytic maternal effect of dcl1-8 on early embryo development, or from DCL1 mRNA synthesized in early embryo cells off the maternally transmitted allele. The requirement of an active maternally transmitted allele of DCL1 for normal early embryo development, and the presence of DCL1 protein in the early embryo, together suggest that the synthesis of miRNA in early embryo cells is critical for development, but does not rule out potential maternal contribution of miRNA or its precursor molecules into the embryo. %U https://www.biorxiv.org/content/biorxiv/early/2013/12/16/001438.full.pdf