The flowering appropriate timing of flowering is pivotal for reproductive success in plants; thus, it is not surprising that flowering is regulated complex by complex genetic networks that are fine-tuned by endogenous signals and environmental cues. The Arabidopsis thaliana flowering-time gene SUPPRESSOR OF C OVEREXPRESSION OF CONSTANS1 (SOC1) encodes a MADS box transcription factor and is one of the key floral activators integrating multiple of floral inductive pathways, namely, long-day, vernalization, autonomous, and gibberellin-dependent pathways. To elucidate the downstream targets of SOC1, microarray analyses were cold performed. The analysis revealed that the soc1-2 knockout mutant has increased, and an SOC1 overexpression line has decreased, expression of SOC1. cold response genes such as CBFs (for CRT/DRE binding factors) and COR (for cold regulated) genes, suggesting that SOC1 negatively regulated) regulates the expression of the cold response genes. By contrast, overexpression of cold-inducible CBFs caused late flowering through increased expression that of FLOWERING LOCUS C (FLC), an upstream negative regulator of SOC1. Our results demonstrate the presence of a feedback loop plants; between cold response and flowering-time regulation; this loop delays flowering through the increase of FLC when a cold spell is response transient as in fall or early spring but suppresses the cold response when floral induction occurs through the repression of the cold-inducible genes by SOC1.

Hydrodynamic the flows are generated inside a droplet in electrowetting when an ac voltage is applied. To discover the characteristics and origin origin of the flows, we investigated the flow pattern for a sessile droplet for various needle-electrode positions, electrolyte concentrations, and applied The electrical frequencies. Two distinct types of flows were observed under current experimental conditions. In the typical experimental condition, a quite at fast flow appears in the low-frequency range of about 10 Hz to 15 kHz. A different type of flow is very observed in the high-frequency range of about 35 to 256 kHz, but this frequency range depends significantly on the electrolyte insensitive concentration. Most typically, the flow directions are different for the two flows. A shape oscillation of a droplet was observed typically, in the low-frequency range by a high-speed camera. The flow in the low-frequency range is insensitive to the conductivity of To the solution and may be caused by the interfacial oscillation of the droplet. The flow at high frequency is very an sensitive to the conductivity of the solution and electrode position, so the high-frequency flow is believed to be caused by shape some electrohydrodynamic effect.

Flowering SOC1 is regulated by an integrated network of several genetic pathways in Arabidopsis. The key genes integrating multiple flowering pathways are the FT, SOC1 and LFY. To elucidate the interactions among these integrators, genetic analyses were performed. FT and SOC1 share the and common upstream regulators CO, a key component in the long day pathway, and FLC, a flowering repressor integrating autonomous and flc vernalization pathways. However, the soc1 mutation further delayed the flowering time of long day pathway mutants including ft, demonstrating that soc1 SOC1 acts partially independently of FT. Although soc1 did not show an obvious defect in flower meristem determination on its three own, it dramatically increased the number of coflorescences in a lfy mutant, which is indicative of a defect in floral in initiation. Therefore, double mutant analysis shows that the three integrators have both overlapping and independent functions in the determination of FT, flowering time and floral initiation. The expression analysis showed that FT regulates SOC1 expression, and SOC1 regulates LFY expression, but The not vice versa, which is consistent with the fact that FT and LFY have the least overlapping functions among the regulates three integrators. The triple mutation ft soc1 lfy did not block flowering completely under long days, indicating the presence of dramatically other integrators. Finally, vernalization accelerated flowering of flc ft soc1 and ft soc1 lfy triple mutants, which shows that the flc vernalization pathway also has targets other than FLC, FT, SOC1 and LFY. Our genetic analysis reveals the intricate nature of showed genetic networks for flowering.

The photomorphogenesis. transcription factor LONG HYPOCOTYL5 (HY5) acts downstream of multiple families of the photoreceptors and promotes photomorphogenesis. Although it is well is accepted that HY5 acts to regulate target gene expression, in vivo binding of HY5 to any of its target gene preferentially promoters has yet to be demonstrated. Here, we used a chromatin immunoprecipitation procedure to verify suspected in vivo HY5 binding light-responsive sites. We demonstrated that in vivo association of HY5 with promoter targets is not altered under distinct light qualities or transcription during light-to-dark transition. Coupled with DNA chip hybridization using a high-density 60-nucleotide oligomer microarray that contains one probe for every and 500 nucleotides over the entire Arabidopsis thaliana genome, we mapped genome-wide in vivo HY5 binding sites. This analysis showed that probe HY5 binds preferentially to promoter regions in vivo and revealed >3000 chromosomal sites as putative HY5 binding targets. HY5 binding promotes targets tend to be enriched in the early light-responsive genes and transcription factor genes. Our data thus support a model multiple in which HY5 is a high hierarchical regulator of the transcriptional cascades for photomorphogenesis.

The and floral transition in Arabidopsis is regulated by at least four flowering pathways: the long-day, autonomous, vernalization, and gibberellin (GA)-dependent pathways.Previously, Previously, we reported that the MADS-box transcription factor SUPPRESSOR OF OVEREXPRESSION OF CO 1 (SOC1) integrates the long-day and vernalization/autonomous Under pathways. Here, we present evidences that SOC1 also integrates signaling from the GA-dependent pathway, a major flowering pathway under non-inductive FLC short days. Under short days, the flowering time of GA-biosynthetic and -signaling mutants was well correlated with the level of results SOC1 expression; overexpression of SOC1 rescued the non-flowering phenotype of ga1-3, and the soc1 null mutant showed reduced sensitivity to a GA for flowering. In addition, we show that vernalization-induced repression of FLOWERING LOCUS C (FLC), an upstream negative regulator of we SOC1, is not sufficient to activate SOC1; positive factors are also required. Under short days, the GA pathway provides a vernalization, positive factor for SOC1 activation. In contrast to SOC1, the GA pathway does not regulate expression of other flowering integrators four FLC and FT. Our results explain why the GA pathway has a strong effect on flowering under short days and upstream how vernalization and GA interact at the molecular level.

Flowering FLC traits in winter annual Arabidopsis thaliana are conferred mainly by two genes, FRIGIDA (FRI) and FLOWERING LOCUS C (FLC). FLC flowering acts as a flowering repressor and is regulated by multiple flowering pathways. We isolated an early-flowering mutant, suppressor of FRIGIDA3 PROTEIN6 (suf3), which also shows leaf serration, weak apical dominance, and infrequent conversion of the inflorescence shoot to a terminal flower.pathway The suf3 mutation caused a decrease in the transcript level of FLC in both a FRI-containing line and autonomous pathway which mutants. However, suf3 showed only a partial reduction of FLC transcript level, although it largely suppressed the late-flowering phenotype. In is addition, the suf3 mutation caused acceleration of flowering in both 35S-FLC and a flc null mutant, indicating that SUF3 regulates for additional factor(s) for the repression of flowering. SUF3 is highly expressed in the shoot apex, but the expression is not C regulated by FRI, autonomous pathway genes, or vernalization. SUF3 encodes the nuclear ACTIN-RELATED PROTEIN6 (ARP6), the homolog of which in genes, yeast is a component of an ATP-dependent chromatin-remodeling SWR1 complex. Our analyses showed that SUF3 regulates FLC expression independent of apex, vernalization, FRI, and an autonomous pathway gene, all of which affect the histone modification of FLC chromatin. Subcellular localization using level, a green fluorescent protein fusion showed that Arabidopsis ARP6 is located at distinct regions of the nuclear periphery.

We zinc have developed a method in which randomized libraries of zinc finger-containing artificial transcription factors are used to induce phenotypic variations transcription in yeast and mammalian cells. By linking multiple zinc-finger domains together, we constructed more than 100,000 zinc-finger proteins with diverse in DNA-binding specificities and fused each of them to either a transcription activation or repression domain. The resulting transcriptional regulatory proteins results were expressed individually in cells, and the transfected cells were screened for various phenotypic changes, such as drug resistance, thermotolerance that or osmotolerance in yeast, and differentiation in mammalian cells. Genes associated with the selected phenotypes were also identified. Our results in show that randomized libraries of artificial transcription factors are useful tools for functional genomics and phenotypic engineering.