The ASK1 gene regulates B function gene expression in cooperation with UFO and LEAFY in Arabidopsis

Development ◽  
2001 ◽  
Vol 128 (14) ◽  
pp. 2735-2746
Author(s):  
Dazhong Zhao ◽  
Qilu Yu ◽  
Min Chen ◽  
Hong Ma
Keyword(s):  
Ubiquitin Ligase ◽  
Floral Organ ◽  
Abc Model ◽  
Gene Encoding ◽  
Genetic Studies ◽  
Organ Identity ◽  
F Box Protein ◽  
In Situ Hybridizations ◽  
Floral Regulatory Genes

The Arabidopsis floral regulatory genes APETALA3 (AP3) and PISTILLATA (PI) are required for the B function according to the ABC model for floral organ identity. AP3 and PI expression are positively regulated by the LEAFY (LFY) and UNUSUAL FLORAL ORGANS (UFO) genes. UFO encodes an F-box protein, and we have shown previously that UFO genetically interacts with the ASK1 gene encoding a SKP1 homologue; both the F-box containing protein and SKP1 are subunits of ubiquitin ligases. We show here that the ask1-1 mutation can enhance the floral phenotypes of weak lfy and ap3 mutants; therefore, like UFO, ASK1 also interacts with LFY and AP3 genetically. Furthermore, our results from RNA in situ hybridizations indicate that ASK1 regulates early AP3 and PI expression. These results support the idea that UFO and ASK1 together positively regulate AP3 and PI expression. We propose that the UFO and ASK1 proteins are components of a ubiquitin ligase that mediates the proteolysis of a repressor of AP3 and PI expression. Our genetic studies also indicate that ASK1 and UFO play a role in regulating the number of floral organ primordia, and we discuss possible mechanisms for such a regulation.

scholarly journals Transcriptome-Wide Analyses Provide Insights into Development of the Hedychium Coronarium Flower, Revealing Potential Roles of PTL

2020 ◽  
Author(s):  
Tong Zhao ◽  
Alma Piñeyro-Nelson ◽  
Qianxia Yu ◽  
Xiaoying Hu ◽  
Huanfang Liu ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Flower Development ◽  
Molecular Mechanisms ◽  
Expression Patterns ◽  
Floral Organ ◽  
Mrna In Situ Hybridization ◽  
Hedychium Coronarium ◽  
Organ Identity

Abstract Background:The flower of Hedychium coronarium possesses highly specialized floral organs: a synsepalous calyx, petaloid staminodes and a labellum. The formation of these organs is controlled by two gene categories: floral organ identity genes and organ boundary genes, which may function individually or jointly during flower development. Although the floral organogenesis of H. coronarium has been studied at the morphological level, the underlying molecular mechanisms involved in its floral development still remain poorly understood. In addition, previous works analyzing the role of MADS-box genes in controlling floral organ specification in some Zingiberaceae did not address the molecular mechanisms involved in the formation of particular organ morphologies that emerge later in flower development, such as the synsepalous calyx formed through intercalary growth of adjacent sepals. Results:Here, we used comparative transcriptomics combined with Real-time quantitative PCR and mRNA in situ hybridization to investigate gene expression patterns of ABC-class genes in H. coronarium flowers, as well as the homolog of the organ boundary gene PETAL LOSS (HcPTL). qRT-PCR detection showed that HcAP3 and HcAG were expressed in both the petaloid staminode and the fertile stamen. mRNA in situ hybridization showed that HcPTL was expressed in developing meristems, including cincinnus primordia, floral primordia, common primordia and almost all new initiating floral organ primordia.Conclusions:Our studies found that stamen/petal identity or stamen fertility in H. coronarium was not necessarily correlated with the differential expression of HcAP3 and HcAG. We also found a novel spatio-temporal expression pattern for HcPTL mRNA, suggesting it may have evolved a lineage-specific role in the morphogenesis of the Hedychium flower. Our study provides a new transcriptome reference and a functional hypothesis regarding the role of a boundary gene in organ fusion that should be further addressed through phylogenetic analyzes of this gene, as well as functional studies.

Developmental basis of homeosis in precociously germinating Brassica napus embryos: phase change at the shoot apex

Development ◽  
1997 ◽  
Vol 124 (6) ◽  
pp. 1149-1157
Author(s):  
D.E. Fernandez
Keyword(s):  
Molecular Markers ◽  
Brassica Napus ◽  
Shoot Apex ◽  
Leaf Tissue ◽  
Precocious Germination ◽  
Organ Identity ◽  
The Status ◽  
Mode Characteristic ◽  
In Situ Hybridizations

Precociously germinating Brassica napus (oilseed rape) embryos produce extra cotyledons or chimeric organs with sectors of cotyledon and leaf tissue, rather than leaves, at the shoot apex. To investigate this phenomenon in more detail, scanning electron microscopy was used to examine the development of organ primordia at the shoot apex. In situ hybridizations with molecular markers of the embryonic phase were used to assess the status of individual cells in the shoot apex with regard to the transition between embryonic and vegetative phases. The results indicate that, under conditions that support precocious germination, primordia develop at the shoot apex in the mode characteristic of postgerminative growth, i.e. they arise sequentially in a spiral phyllotaxy. Cells in the rest of the embryo, however, can continue to express molecular markers of the embryonic phase for several weeks after the start of culture. When patterns of gene expression and the fate of individual primordia were compared, a strong correlation was found between organ identity and the status of cells in the vicinity of the meristem with regard to phase. Primordia that develop in situations where neighboring cells are in the embryonic phase always produce organs with cotyledon morphology. Primordia that develop in situations where neighboring cells have exited the embryonic phase produce leaves. Based on an examination of situations where chimeric organs are produced, I propose that short range interactions or signalling are likely to be involved in communicating information about phase to developing primordia.

scholarly journals Fission Yeast F-box Protein Pof3 Is Required for Genome Integrity and Telomere Function

2002 ◽  
Vol 13 (1) ◽  
pp. 211-224 ◽  
Author(s):  
Satoshi Katayama ◽  
Kenji Kitamura ◽  
Anna Lehmann ◽  
Osamu Nikaido ◽  
Takashi Toda
Keyword(s):  
Cell Cycle ◽  
Fission Yeast ◽  
Ubiquitin Ligase ◽  
Repeat Motif ◽  
High Rate ◽  
Genome Integrity ◽  
Gene Encoding ◽  
Cell Cycle Delay ◽  
C Terminus ◽  
F Box Protein

The Skp1-Cullin-1/Cdc53-F-box protein (SCF) ubiquitin ligase plays an important role in various biological processes. In this enzyme complex, a variety of F-box proteins act as receptors that recruit substrates. We have identified a fission yeast gene encoding a novel F-box protein Pof3, which contains, in addition to the F-box, a tetratricopeptide repeat motif in its N terminus and a leucine-rich-repeat motif in the C terminus, two ubiquitous protein–protein interaction domains. Pof3 forms a complex with Skp1 and Pcu1 (fission yeast cullin-1), suggesting that Pof3 functions as an adaptor for specific substrates. In the absence of Pof3, cells exhibit a number of phenotypes reminiscent of genome integrity defects. These include G2 cell cycle delay, hypersensitivity to UV, appearance of lagging chromosomes, and a high rate of chromosome loss.pof3 deletion strains are viable because the DNA damage checkpoint is continuously activated in the mutant, and this leads to G2 cell cycle delay, thereby preventing the mutant from committing lethal mitosis. Pof3 localizes to the nucleus during the cell cycle. Molecular analysis reveals that in this mutant the telomere is substantially shortened and furthermore transcriptional silencing at the telomere is alleviated. The results highlight a role of the SCFPof3 ubiquitin ligase in genome integrity via maintaining chromatin structures.

scholarly journals Null Mutation of AtCUL1 Causes Arrest in Early Embryogenesis in Arabidopsis

2002 ◽  
Vol 13 (6) ◽  
pp. 1916-1928 ◽  
Author(s):  
Wen-Hui Shen ◽  
Yves Parmentier ◽  
Hanjo Hellmann ◽  
Esther Lechner ◽  
Aiwu Dong ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Mammalian Cells ◽  
Critical Role ◽  
Functional Characterization ◽  
Early Embryogenesis ◽  
Cell Cycle Regulators ◽  
Genetic Studies ◽  
Scf Ubiquitin Ligase ◽  
F Box Protein

The SCF (for SKP1, Cullin/CDC53,F-box protein) ubiquitin ligase targets a number of cell cycle regulators, transcription factors, and other proteins for degradation in yeast and mammalian cells. Recent genetic studies demonstrate that plant F-box proteins are involved in auxin responses, jasmonate signaling, flower morphogenesis, photocontrol of circadian clocks, and leaf senescence, implying a large spectrum of functions for the SCF pathway in plant development. Here, we present a molecular and functional characterization of plant cullins. TheArabidopsis genome contains 11 cullin-related genes. Complementation assays revealed that AtCUL1 but not AtCUL4 can functionally complement the yeast cdc53 mutant.Arabidopsis mutants containing transfer DNA (T-DNA) insertions in the AtCUL1 gene were shown to display an arrest in early embryogenesis. Consistently, both the transcript and the protein of the AtCUL1 gene were found to accumulate in embryos. The AtCUL1 protein localized mainly in the nucleus but also weakly in the cytoplasm during interphase and colocalized with the mitotic spindle in metaphase. Our results demonstrate a critical role for the SCF ubiquitin ligase inArabidopsis embryogenesis.

scholarly journals Function and Diversification of MADS-Box Genes in Rice

2006 ◽  
Vol 6 ◽  
pp. 1923-1932 ◽  
Author(s):  
Takahiro Yamaguchi ◽  
Hiro-Yuki Hirano
Keyword(s):  
Flower Development ◽  
Floral Organ ◽  
Flowering Plants ◽  
Grass Species ◽  
Mads Box ◽  
Mads Box Genes ◽  
Genetic Studies ◽  
Floral Diversity ◽  
Organ Identity ◽  
Mads Box Gene

MADS-box genes play critical roles in a number of developmental processes in flowering plants, such as specification of floral organ identity, control of flowering time, and regulation of fruit development. Because of their crucial functions in flower development, diversification of the MADS-box gene family has been suggested to be a major factor responsible for floral diversity during radiation of the flowering plants. Inflorescences and flowers in the grass species have unique structures that are distinct from those in eudicots. Thus, it is plausible that the diversification of the function of MADS-box genes may have been a key driving force in the morphological divergence of the flowers and inflorescences in the grasses. Indeed, recent progress in genetic studies has shown that MADS-box genes function in flower development inOryza sativa(rice), in support of the idea that functional diversification of the MADS-box genes was involved in evolution of the angiosperms. In this review, we summarize the functions of the major subfamilies of the MADS-box genes in rice and discuss their role in the development and evolution of rice flowers and inflorescences.

scholarly journals SCFCdc4 ubiquitin ligase regulates synaptonemal complex formation during meiosis

2020 ◽  
Vol 4 (2) ◽  
pp. e202000933
Author(s):  
Zhihui Zhu ◽  
Mohammad Bani Ismail ◽  
Miki Shinohara ◽  
Akira Shinohara
Keyword(s):  
Synaptonemal Complex ◽  
Ubiquitin Ligase ◽  
Meiotic Recombination ◽  
Critical Role ◽  
Temperature Sensitive ◽  
Dna Double Strand Breaks ◽  
Gene Encoding ◽  
Aaa Atpase ◽  
Dependent Protein ◽  
F Box Protein

Homologous chromosomes pair with each other during meiosis, culminating in the formation of the synaptonemal complex (SC), which is coupled with meiotic recombination. In this study, we showed that a meiosis-specific depletion mutant of a cullin (Cdc53) in the SCF (Skp-Cullin-F-box) ubiquitin ligase, which plays a critical role in cell cycle regulation during mitosis, is deficient in SC formation. However, the mutant is proficient in forming crossovers, indicating the uncoupling of meiotic recombination with SC formation in the mutant. Furthermore, the deletion of the PCH2 gene encoding a meiosis-specific AAA+ ATPase suppresses SC-assembly defects induced by CDC53 depletion. On the other hand, the pch2 cdc53 double mutant is defective in meiotic crossover formation, suggesting the assembly of SC with unrepaired DNA double-strand breaks. A temperature-sensitive mutant of CDC4, which encodes an F-box protein of SCF, shows meiotic defects similar to those of the CDC53-depletion mutant. These results suggest that SCFCdc4, probably SCFCdc4-dependent protein ubiquitylation, regulates and collaborates with Pch2 in SC assembly and meiotic recombination.

Localization of ADAMTS13 to the stellate cells of human liver

Blood ◽  
2005 ◽  
Vol 106 (3) ◽  
pp. 922-924 ◽  
Author(s):  
Masahito Uemura ◽  
Kouko Tatsumi ◽  
Masanori Matsumoto ◽  
Masao Fujimoto ◽  
Tomomi Matsuyama ◽  
...  
Keyword(s):  
Human Liver ◽  
Smooth Muscle Actin ◽  
Stellate Cells ◽  
Human Form ◽  
Gene Encoding ◽  
Double Labeling ◽  
Fresh Frozen ◽  
Liver Biopsies ◽  
In Situ Hybridizations

Abstract Although the chromosomal localization (9q34) of the gene encoding the human form of ADAMTS13 (a disintegrin-like and metalloproteinase with thrombospondin type-1 motifs 13) and its exclusive expression in the liver have been established, the cells that produce this enzyme are yet to be determined. We investigated the expression of ADAMTS13 mRNA and protein in fresh frozen specimens obtained during liver biopsies of 8 patients with liver diseases. In situ hybridizations to localize ADAMTS13 mRNA showed positive signals exclusively in perisinusoidal cells with irregularly elongated dendritic processes extending between hepatocytes. Furthermore, ADAMTS13 was detected immunohistochemically in perisinusoidal cells, whereas no staining was observed in hepatocytes. The positive cells varied in shape from unipolar to dendritic with irregularly elongated cytoplasmic processes, features common to hepatic stellate cells (HSCs). Double-labeling experiments revealed that the ADAMTS13-positive cells also expressed α-smooth muscle actin, confirming that these cells were activated HSCs. These results suggest that HSCs may be major cells producing ADAMTS13 in human liver.

scholarly journals SCFCdc4 ubiquitin ligase regulates synaptonemal complex formation during meiosis

2020 ◽  
Author(s):  
Zhihui Zhu ◽  
Mohammad Bani Ismail ◽  
Miki Shinohara ◽  
Akira Shinohara
Keyword(s):  
Synaptonemal Complex ◽  
Ubiquitin Ligase ◽  
Meiotic Recombination ◽  
Critical Role ◽  
Temperature Sensitive ◽  
Gene Encoding ◽  
Homologous Chromosomes ◽  
Aaa Atpase ◽  
F Box Protein ◽  
Cycle Regulation

AbstractHomologous chromosomes pair with each other during meiosis, culminating in the formation of the synaptonemal complex (SC), which is coupled with meiotic recombination. In this study, we showed that a meiosis-specific depletion mutant of a cullin (Cdc53) of the SCF (Skp-Cullin-F-box) ubiquitin ligase, which plays a critical role in cell cycle regulation during mitosis, is deficient in SC formation, but is proficient in the formation of crossovers, indicating uncoupling of meiotic recombination with SC formation in the mutant. Furthermore, the deletion of the PCH2 gene encoding a meiosis-specific AAA+ ATPase suppresses SC-assembly defect induced by CDC53 depletion. On the other hand, the pch2 cdc53 double mutant is defective in meiotic crossover formation, suggesting the SC assembly with unrepaired DSBs. A temperature-sensitive mutant of the CDC4, which encodes a F-box protein of the SCF, shows similar meiotic defects to the CDC53 depletion mutant. These suggest that SCFCdc4, probably SCFCdc4-dependnet protein ubiquitylation, regulates and collaborates with Pch2 in SC assembly and meiotic recombination.SummaryDuring meiosis, homologous chromosomes pair with each other and form the synaptonemal complex (SC). In this study, components of the SCF (Skp-Cullin-F-box) ubiquitin ligase, Cdc53 and Cdc4, are required for SC formation. A meiosis-specific AAA+ ATPase Pch2 antagonize the functions of Cdc53 and Cdc4 for proper SC assembly.

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