Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 7 de 7
Filter
Add more filters










Database
Language
Publication year range
1.
Proc Natl Acad Sci U S A ; 110(4): E285-94, 2013 Jan 22.
Article in English | MEDLINE | ID: mdl-23277562

ABSTRACT

SMG1 is a member of the phosphoinositide kinase-like kinase family of proteins that includes ATM, ATR, and DNA-PK, proteins with known roles in DNA damage and cellular stress responses. SMG1 has a well-characterized role in nonsense-mediated decay as well as suggested roles in the DNA damage response, resistance to oxidative stress, regulation of hypoxic responses, and apoptosis. To understand the roles of SMG1 further, we generated a Genetrap Smg1 mouse model. Smg1 homozygous KO mice were early embryonic lethal, but Smg1 heterozygous mice showed a predisposition to a range of cancers, particularly lung and hematopoietic malignancies, as well as development of chronic inflammation. These mice did not display deficiencies in known roles of SMG1, including nonsense-mediated decay. However, they showed elevated basal tissue and serum cytokine levels, indicating low-level inflammation before the development of tumors. Smg1 heterozygous mice also showed evidence of oxidative damage in tissues. These data suggest that the inflammation observed in Smg1 haploinsufficiency contributes to susceptibility to cancer and that Smg1-deficient animals represent a model of inflammation-enhanced cancer development.


Subject(s)
Inflammation/genetics , Neoplasms, Experimental/genetics , Protein Serine-Threonine Kinases/deficiency , Protein Serine-Threonine Kinases/genetics , Animals , Base Sequence , DNA, Complementary/genetics , Disease Models, Animal , Genetic Predisposition to Disease , Haploinsufficiency , Hematologic Neoplasms/enzymology , Hematologic Neoplasms/etiology , Hematologic Neoplasms/genetics , Hematologic Neoplasms/pathology , Homozygote , Inflammation/complications , Inflammation/enzymology , Inflammation/pathology , Lung Neoplasms/enzymology , Lung Neoplasms/etiology , Lung Neoplasms/genetics , Lung Neoplasms/pathology , Mice , Mice, 129 Strain , Mice, Inbred C57BL , Mice, Knockout , Molecular Sequence Data , Neoplasms, Experimental/enzymology , Neoplasms, Experimental/etiology , Neoplasms, Experimental/pathology
2.
Physiol Genomics ; 31(1): 126-38, 2007 Sep 19.
Article in English | MEDLINE | ID: mdl-17566080

ABSTRACT

Cultured shrimp are continuously exposed to variable environmental conditions that have been associated with stress and subsequent outbreaks of disease. To investigate the effect of environmental stress on Penaeus monodon gene expression, a 3,853 random cDNA microarray chip was generated with clones originating from six stress-enriched hemocyte libraries generated by suppression subtractive hybridization and a normal hemocyte cDNA library. Changes in temporal gene expression were analyzed from shrimp exposed to hypoxic, hyperthermic, and hypoosmotic conditions; 3.1% of the cDNAs were differentially expressed in response to at least one of the environmental stressors, and 72% of the differentially expressed clones had no significant sequence similarity to previously known genes. Among those genes with high identity to known sequences, the most common functional groups were immune-related genes and non-long terminal repeat retrotransposons. Hierarchical clustering revealed a set of cDNAs with temporal and stress-specific gene expression profiles as well as a set of cDNAs indicating a common stress response between stressors. Hypoxic and hyperthermic stressors induced the most severe short-term response in terms of gene regulation, and the osmotic stress had the least variation in expression profiles relative to the control. These expression data agree with observed differences in shrimp physical appearance and behavior following exposure to stress conditions.


Subject(s)
Gene Expression Profiling , Gene Expression Regulation , Animals , Cluster Analysis , DNA, Complementary/metabolism , Gene Library , Hemocytes/metabolism , Hypoxia , Immune System , Nucleic Acid Hybridization , Oligonucleotide Array Sequence Analysis , Osmosis , Penaeidae , Retroelements , Sequence Analysis, DNA
3.
Cancer Res ; 65(5): 1670-7, 2005 Mar 01.
Article in English | MEDLINE | ID: mdl-15753361

ABSTRACT

Previous reports have suggested a connection between reduced levels of the catalytic subunit of DNA-dependent protein kinases (DNA-PKcs), a component of the nonhomologous DNA double-strand breaks end-joining system, and a reduction in ATM. We studied this possible connection in other DNA-PKcs-deficient cell types, and following knockdown of DNA-PKcs with small interfering RNA, Chinese hamster ovary V3 cells, lacking DNA-PKcs, had reduced levels of ATM and hSMG-1, but both were restored after transfection with PRKDC. Atm levels were also reduced in murine scid cells. Reduction of ATM in a human glioma cell line lacking DNA-PKcs was accompanied by defective signaling through downstream substrates, post-irradiation. A large reduction of DNA-PKcs was achieved in normal human fibroblasts after transfection with two DNA-PKcs small interfering RNA sequences. This was accompanied by a reduction in ATM. These data were confirmed using immunocytochemical detection of the proteins. Within hours after transfection, a decline in PRKDC mRNA was seen, followed by a more gradual decline in DNA-PKcs protein beginning 1 day after transfection. No change in ATM mRNA was observed for 2 days post-transfection. Only after the DNA-PKcs reduction occurred was a reduction in ATM mRNA observed, beginning 2 days post-transfection. The amount of ATM began to decline, starting about 3 days post-treatment, then it declined to levels comparable to DNA-PKcs. Both proteins returned to normal levels at later times. These data illustrate a potentially important cross-regulation between the nonhomologous end-joining system for rejoining of DNA double-strand breaks and the ATM-dependent damage response network of pathways, both of which operate to maintain the integrity of the genome.


Subject(s)
Cell Cycle Proteins/metabolism , DNA-Binding Proteins , DNA-Binding Proteins/metabolism , DNA/genetics , Gene Expression Regulation , Protein Serine-Threonine Kinases , Protein Serine-Threonine Kinases/metabolism , Tumor Suppressor Proteins/metabolism , Animals , Antigens, Surface , Ataxia Telangiectasia/metabolism , Ataxia Telangiectasia Mutated Proteins , CHO Cells , Catalytic Domain , Cell Cycle Proteins/genetics , Cricetinae , DNA/metabolism , DNA/radiation effects , DNA Damage/genetics , DNA Repair/genetics , DNA-Activated Protein Kinase , DNA-Binding Proteins/antagonists & inhibitors , DNA-Binding Proteins/genetics , Down-Regulation , Fibroblasts/metabolism , Fibroblasts/pathology , Glioma/metabolism , Glioma/pathology , Humans , Immunoenzyme Techniques , Membrane Proteins/genetics , Membrane Proteins/metabolism , Nuclear Proteins , Protein Serine-Threonine Kinases/antagonists & inhibitors , Protein Serine-Threonine Kinases/genetics , Protein Subunits , RNA, Messenger/genetics , RNA, Messenger/metabolism , RNA, Small Interfering/pharmacology , Transfection , Tumor Suppressor Proteins/genetics
4.
FEMS Microbiol Lett ; 241(2): 243-8, 2004 Dec 15.
Article in English | MEDLINE | ID: mdl-15598539

ABSTRACT

The production of lipase and protease from psychrotrophic strains of Pseudomonas fluorescens may result in spoilage of dairy products. The lipase (lipA) and alkaline metalloprotease (aprX) genes of P. fluorescens B52 are regulated by temperature and are located at opposite ends of an operon which contains eight genes and spans 14 kb. In this report, we show that lipase activity in the supernatant of cultures of P. fluorescens strain B52 is also regulated by the homologue of the Escherichia coli EnvZ-OmpR two-component regulatory system. Differences in the regulation of lipase and protease may be related to the proximal and distal locations of aprX and lipA within the operon.


Subject(s)
Bacterial Outer Membrane Proteins/metabolism , Bacterial Proteins/metabolism , Carboxylic Ester Hydrolases/metabolism , Escherichia coli Proteins/metabolism , Gene Expression Regulation, Enzymologic , Multienzyme Complexes/metabolism , Operon , Pseudomonas fluorescens/enzymology , Serine Endopeptidases/metabolism , Trans-Activators/metabolism , Bacterial Outer Membrane Proteins/genetics , Bacterial Proteins/genetics , Carboxylic Ester Hydrolases/genetics , Escherichia coli/enzymology , Escherichia coli/genetics , Escherichia coli Proteins/genetics , Gene Expression Regulation, Bacterial , Lipase , Molecular Sequence Data , Multienzyme Complexes/genetics , Pseudomonas fluorescens/genetics , Pseudomonas fluorescens/growth & development , Sequence Analysis, DNA , Serine Endopeptidases/genetics , Trans-Activators/genetics
5.
Development ; 131(12): 2921-33, 2004 Jun.
Article in English | MEDLINE | ID: mdl-15169757

ABSTRACT

Hemps, a novel epidermal growth factor (EGF)-like protein, is expressed during larval development and early metamorphosis in the ascidian Herdmania curvata and plays a direct role in triggering metamorphosis. In order to identify downstream genes in the Hemps pathway we used a gene expression profiling approach, in which we compared post-larvae undergoing normal metamorphosis with larval metamorphosis blocked with an anti-Hemps antibody. Molecular profiling revealed that there are dynamic changes in gene expression within the first 30 minutes of normal metamorphosis with a significant portion of the genome (approximately 49%) being activated or repressed. A more detailed analysis of the expression of 15 of these differentially expressed genes through embryogenesis, larval development and metamorphosis revealed that while there is a diversity of temporal expression patterns, a number of genes are transiently expressed during larval development and metamorphosis. These and other differentially expressed genes were localised to a range of specific cell and tissue types in Herdmania larvae and post-larvae. The expression of approximately 24% of the genes that were differentially expressed during early metamorphosis was affected in larvae treated with the anti-Hemps antibody. Knockdown of Hemps activity affected the expression of a range of genes within 30 minutes of induction, suggesting that the Hemps pathway directly regulates early response genes at metamorphosis. In most cases, it appears that the Hemps pathway contributes to the modulation of gene expression, rather than initial gene activation or repression. A total of 151 genes that displayed the greatest alterations in expression in response to anti-Hemps antibody were sequenced. These genes were implicated in a range of developmental and physiological roles, including innate immunity, signal transduction and in the regulation of gene transcription. These results suggest that there is significant gene activity during the very early stages of H. curvata metamorphosis and that the Hemps pathway plays a key role in regulating the expression of many of these genes.


Subject(s)
Epidermal Growth Factor/genetics , Growth Substances/genetics , Metamorphosis, Biological/physiology , Urochordata/embryology , Urochordata/growth & development , Animals , Body Patterning/genetics , Gene Expression Profiling , Gene Expression Regulation, Developmental/genetics , Morphogenesis/genetics , Oligonucleotide Array Sequence Analysis , Signal Transduction , Transcription, Genetic/genetics , Transcriptional Activation , Urochordata/genetics
6.
Microbiology (Reading) ; 147(Pt 2): 345-354, 2001 Feb.
Article in English | MEDLINE | ID: mdl-11158351

ABSTRACT

Extracellular protease and lipase production by psychrotrophic strains of Pseudomonas fluorescens is repressed by iron and regulated by temperature. The regulation of protease and lipase has been investigated in P. fluorescens B52. Whereas lipase production is increased below the optimum growth temperature ('low-temperature regulation'), protease production was relatively constant and only decreased above the optimum growth temperature. The genes encoding protease (aprX) and lipase (lipA) are encoded at opposite ends of a contiguous set of genes which also includes protease inhibitor, Type I secretion functions and two autotransporter proteins. Evidence is presented indicating that these genes constitute an operon, with a promoter adjacent to aprX which has been identified by S1 nuclease analysis. The regulation of aprX and lipA has been investigated at the RNA level and using lacZ fusion strains. Whereas the data are consistent with iron regulation at the transcriptional level, a lipA'-'lacZ fusion is not regulated by temperature, suggesting that temperature regulation is post-transcriptional or post-translational. The possibility of regulation at the level of mRNA decay is discussed.


Subject(s)
Carboxylic Ester Hydrolases/genetics , Gene Expression Regulation, Bacterial , Operon/genetics , Pseudomonas fluorescens/enzymology , Serine Endopeptidases/genetics , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Base Sequence , Carboxylic Ester Hydrolases/biosynthesis , Endopeptidases/genetics , Endopeptidases/metabolism , Iron/metabolism , Lac Operon/genetics , Lac Operon/physiology , Lipase , Molecular Sequence Data , Promoter Regions, Genetic/genetics , Pseudomonas fluorescens/genetics , Pseudomonas fluorescens/growth & development , Recombinant Fusion Proteins/genetics , Recombinant Fusion Proteins/metabolism , Serine Endopeptidases/biosynthesis , Temperature , Transcription, Genetic
7.
Microbiology (Reading) ; 146 Pt 12: 3149-3155, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11101673

ABSTRACT

The production of extracellular enzymes by Pseudomonas fluorescens is important with respect to phytopathogenesis and, in the case of psychrotrophic strains, food spoilage. The production of extracellular protease has been previously reported to be dependent on temperature in psychrotrophic strains of P. fluorescens; production is decreased above the optimum growth temperature with a relatively small change in growth rate. In this work, a transposon mutant of P. fluorescens LS107d2 has been isolated which, in contrast to the wild-type strain, is completely protease deficient at 29 degrees C, above the optimum growth temperature of 25 degrees C, but which produces protease at 23 degrees C. Further analysis revealed that this mutation is in a gene (prtR) which is part of a dicistronic operon, prtIR, in which the two genes are translationally coupled. Evidence is presented that prtI encodes a sigma factor related to others involved in extracytoplasmic functions (ECF sigma factors) and that prtR encodes a novel transmembrane activator of PrtI. PrtI, like PrtR, is also required for protease production at 29 degrees C but not at 23 degrees C. Analysis of the amino acid sequence of PrtR indicates that it is functionally related to a group of membrane-associated anti-sigma factors and a few transmembrane regulators, but is not significantly sequence related. Complementation analysis indicates that PrtR may also interact with sigma factors other than PrtI. The promoter region of the protease-encoding gene (aprX) in LS107d2 has been identified and has sequence features which could indicate interaction with either an ECF sigma factor or a primary sigma factor.


Subject(s)
Endopeptidases/genetics , Gene Expression Regulation, Bacterial , Pseudomonas fluorescens/enzymology , Sigma Factor/genetics , Transcription Factors/genetics , Base Sequence , DNA Transposable Elements/genetics , Endopeptidases/metabolism , Gene Expression Regulation, Enzymologic , Genetic Complementation Test , Molecular Sequence Data , Mutagenesis, Insertional , Operon , Peroxidases/genetics , Promoter Regions, Genetic/genetics , Pseudomonas fluorescens/genetics , Pseudomonas fluorescens/growth & development , Sigma Factor/metabolism , Temperature , Transcription Factors/metabolism
SELECTION OF CITATIONS
SEARCH DETAIL
...