Positional cloning and characterization reveal the molecular basis for soybean maturity locus E1 that regulates photoperiodic flowering.
ABSTRACT The complex and coordinated regulation of flowering has high ecological and agricultural significance. The maturity locus E1 has a large impact on flowering time in soybean, but the molecular basis for the E1 locus is largely unknown. Through positional cloning, we delimited the E1 locus to a 17.4-kb region containing an intron-free gene (E1). The E1 protein contains a putative bipartite nuclear localization signal and a region distantly related to B3 domain. In the recessive allele, a nonsynonymous substitution occurred in the putative nuclear localization signal, leading to the loss of localization specificity of the E1 protein and earlier flowering. The early-flowering phenotype was consistently observed in three ethylmethanesulfonate-induced mutants and two natural mutations that harbored a premature stop codon or a deletion of the entire E1 gene. E1 expression was significantly suppressed under short-day conditions and showed a bimodal diurnal pattern under long-day conditions, suggesting its response to photoperiod and its dominant effect induced by long day length. When a functional E1 gene was transformed into the early-flowering cultivar Kariyutaka with low E1 expression, transgenic plants carrying exogenous E1 displayed late flowering. Furthermore, the transcript abundance of E1 was negatively correlated with that of GmFT2a and GmFT5a, homologues of FLOWERING LOCUS T that promote flowering. These findings demonstrated the key role of E1 in repressing flowering and delaying maturity in soybean. The molecular identification of the maturity locus E1 will contribute to our understanding of the molecular mechanisms by which a short-day plant regulates flowering time and maturity.
Article: Successful repair of a damaged duodenal stent by cutting stent wires and placement of a second stent.[show abstract] [hide abstract]
ABSTRACT: Duodenal stenting has been gradually established in recent years because it is less invasive than standard surgical procedures and produces a rapid therapeutic response. For palliation of both duodenal and biliary stenoses, double stenting may be performed. Duodenal stents offer a great advantage in allowing endoscopic retrograde cholangiopancreatography (ERCP) without the need for balloon dilation. When biliary stent dysfunction occurs, the patient undergoes diagnostic and/or therapeutic ERCP across the duodenal stent. We encountered a duodenal stent fracture in a patient who required repeated ERCPs for stent dysfunction. Duodenal stent fractures have not previously been reported. The damaged stent was successfully repaired by using a cutting wire filament and placing another duodenal stent coaxially with the first. Clinicians should be aware of the possibility of stent fracture following endoscopic procedures, such as an ERCP, that require passage through the stent. The procedure described in this report would be of significant benefit if a gastrointestinal stent is fractured and occluded by a broken part.Endoscopy 02/2002; 34(1):86-8. · 5.21 Impact Factor
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ABSTRACT: In a genetic screen of available T-DNA-mutagenized Arabidopsis populations for loci potentially involved in phytochrome (phy) signaling, we identified a mutant that displayed reduced seedling deetiolation under continuous red light, but little if any change in responsiveness to continuous far-red light. This behavior suggests disruption of phyB, but not phyA signaling. We have cloned the mutant locus by using the T-DNA insertion and found that the disrupted gene is identical to the recently described GIGANTEA (GI) gene identified as being involved in control of flowering time. The encoded GI polypeptide has no sequence similarity to any known proteins in the database. However, by using beta-glucuronidase-GI and green fluorescent protein-GI fusion constructs, we have shown that GI is constitutively targeted to the nucleus in transient transfection assays. Optical sectioning by using the green fluorescent protein-GI fusion protein showed green fluorescence throughout the nucleoplasm. Thus, contrary to previous computer-based predictions that GI would be an integral plasma membrane-localized polypeptide, the data here indicate that it is a nucleoplasmically localized protein. This result is consistent with the proposed role in phyB signaling, given recent evidence that early phy signaling events are nuclear localized.Proceedings of the National Academy of Sciences 09/2000; 97(17):9789-94. · 9.68 Impact Factor
Journal of anatomy and physiology. 02/1884; 18(Pt 2):182-97.