Thymine-starvation up-regulates a region of theArabidopsis thaliana chromosome III containing both the UMP synthase gene and a proximal gene encoding a novel 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.

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

Development ◽

10.1242/dev.128.14.2735 ◽

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.

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SMC1: an essential yeast gene encoding a putative head-rod-tail protein is required for nuclear division and defines a new ubiquitous protein family.

The Journal of Cell Biology ◽

10.1083/jcb.123.6.1635 ◽

1993 ◽

Vol 123 (6) ◽

pp. 1635-1648 ◽

Cited By ~ 173

Author(s):

A V Strunnikov ◽

V L Larionov ◽

D Koshland

Keyword(s):

Nuclear Division ◽

Coiled Coil ◽

Eukaryotic Cell ◽

Fundamental Aspect ◽

Nucleoside Triphosphate ◽

Gene Encoding ◽

Amino Terminal ◽

New Family ◽

Chromosome Iii ◽

Carboxy Terminal

The smc1-1 mutant was identified initially as a mutant of Saccharomyces cerevisiae that had an elevated rate of minichromosome nondisjunction. We have cloned the wild-type SMC1 gene. The sequence of the SMC1 gene predicts that its product (Smc1p) is a 141-kD protein, and antibodies against Smc1 protein detect a protein with mobility of 165 kD. Analysis of the primary and putative secondary structure of Smc1p suggests that it contains two central coiled-coil regions flanked by an amino-terminal nucleoside triphosphate (NTP)-binding head and a conserved carboxy-terminal tail. These analyses also indicate that Smc1p is an evolutionary conserved protein and is a member of a new family of proteins ubiquitous among prokaryotes and eukaryotes. The SMC1 gene is essential for viability. Several phenotypic characteristics of the mutant alleles of smc1 gene indicate that its product is involved in some aspects of nuclear metabolism, most likely in chromosome segregation. The smc1-1 and smc1-2 mutants have a dramatic increase in mitotic loss of a chromosome fragment and chromosome III, respectively, but have no increase in mitotic recombination. Depletion of SMC1 function in the ts mutant, smc1-2, causes a dramatic mitosis-related lethality. Smc1p-depleted cells have a defect in nuclear division as evidenced by the absence of anaphase cells. This phenotype of the smc1-2 mutant is not RAD9 dependent. Based upon the facts that Smc1p is a member of a ubiquitous family, and it is essential for yeast nuclear division, we propose that Smc1p and Smc1p-like proteins function in a fundamental aspect of prokaryotic and eukaryotic cell division.

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Expression profile of gene encoding Kelch repeat containing F-box protein (PmF-box1) in relation to the production of green leaf volatiles

Australian Journal of Crop Science ◽

10.21475/ajcs.17.11.04.pne290 ◽

2017 ◽

Vol 11 (04) ◽

pp. 406-418 ◽

Cited By ~ 2

Author(s):

Muhamad Hafiz Che Othman ◽

◽

Nurmahfuzah Abd Hadi ◽

Zamri Zainal ◽

Chew Jin Kiat ◽

...

Keyword(s):

Expression Profile ◽

Green Leaf Volatiles ◽

Green Leaf ◽

Gene Encoding ◽

Leaf Volatiles ◽

F Box Protein

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Molecular Characterization and Tissue Localization of an F-Box Only Protein from Silkworm,Bombyx mori

Comparative and Functional Genomics ◽

10.1155/2009/416040 ◽

2009 ◽

Vol 2009 ◽

pp. 1-8

Author(s):

Yafang Shen ◽

Tiancheng Zhang ◽

Jianqing Chen ◽

Zhengbing Lv ◽

Jian Chen ◽

...

Keyword(s):

Cell Cycle Progression ◽

Bioinformatic Analysis ◽

Gene Encoding ◽

Cycle Progression ◽

Low Degree ◽

Silkworm Pupae ◽

Regulation Of Cell Cycle ◽

F Box Protein ◽

Degree Of Similarity ◽

Different Levels

The eukaryotic F-box protein family is characterized by an F-box motif that has been shown to be critical for the controlled degradation of regulatory proteins. We identified a gene encoding an F-box protein from a cDNA library of silkworm pupae, which has an ORF of 1821 bp, encoding a predicted 606 amino acids. Bioinformatic analysis on the amino acid sequence shows that BmFBXO21 has a low degree of similarity to proteins from other species, and may be related to the regulation of cell-cycle progression. We have detected the expression pattern of BmFBXO21 mRNA and protein and performed immunohistochemistry at three different levels. Expression was highest in the spinning stage, and in the tissues of head, epidermis, and genital organs.

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Control of Paternally Expressed Imprinted UPWARD CURLY LEAF1, a Gene Encoding an F-Box Protein That Regulates CURLY LEAF Polycomb Protein, in the Arabidopsis Endosperm

PLoS ONE ◽

10.1371/journal.pone.0117431 ◽

2015 ◽

Vol 10 (2) ◽

pp. e0117431 ◽

Cited By ~ 4

Author(s):

Cheol Woong Jeong ◽

Guen Tae Park ◽

Hyein Yun ◽

Tzung-Fu Hsieh ◽

Yang Do Choi ◽

...

Keyword(s):

Gene Encoding ◽

Polycomb Protein ◽

F Box Protein ◽

Curly Leaf

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SCFCdc4 ubiquitin ligase regulates synaptonemal complex formation during meiosis

Life Science Alliance ◽

10.26508/lsa.202000933 ◽

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.

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