1
|
Mazepa E, Furlanetto ALDDM, Brum H, Nakao LS, Martinez PA, Cadena SMSC, Rocha MEM, Cunha ES, Martinez GR. Effects of redox modulation on quiescin/sulfhydryl oxidase activity of melanoma cells. Mol Cell Biochem 2024; 479:511-524. [PMID: 37103678 DOI: 10.1007/s11010-023-04745-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 04/14/2023] [Indexed: 04/28/2023]
Abstract
Secreted quiescin/sulfhydryl oxidase (QSOX) is overexpressed in many tumor cell lines, including melanoma, and is usually associated with a pro-invasive phenotype. Our previous work described that B16-F10 cells enter in a quiescent state as a protective mechanism against damage generated by reactive oxygen species (ROS) during melanogenesis stimulation. Our present results show that QSOX activity was two-fold higher in cells with stimulated melanogenesis when compared to control cells. Considering that glutathione (GSH) is one of the main factor responsible for controlling redox homeostasis in cells, this work also aimed to investigate the relationship between QSOX activity, GSH levels and melanogenesis stimulation in B16-F10 murine melanoma cell line. The redox homeostasis was impaired by treating cells with GSH in excess or depleting its intracellular levels through BSO treatment. Interestingly, GSH-depleted cells without stimulation of melanogenesis kept high levels of viability, suggesting a possible adaptive mechanism of survival even under low GSH levels. They also showed lower extracellular activity of QSOX, and higher QSOX intracellular immunostaining, suggesting that this enzyme was less excreted from cells and corroborating with a diminished extracellular QSOX activity. On the other hand, cells under melanogenesis stimulation showed a lower GSH/GSSG ratio (8:1) in comparison with control (non-stimulated) cells (20:1), indicating a pro-oxidative state after stimulation. This was accompanied by decreased cell viability after GSH-depletion, no alterations in QSOX extracellular activity, but higher QSOX nucleic immunostaining. We suggest that melanogenesis stimulation and redox impairment caused by GSH-depletion enhanced the oxidative stress in these cells, contributing to additional alterations of its metabolic adaptive response.
Collapse
Affiliation(s)
- Ester Mazepa
- Postgraduate Program in Sciences (Biochemistry), Department of Biochemistry and Molecular Biology, UFPR, Curitiba, PR, Brazil
| | | | - Hulyana Brum
- Postgraduate Program in Sciences (Biochemistry), Department of Biochemistry and Molecular Biology, UFPR, Curitiba, PR, Brazil
| | | | | | | | - Maria Eliane Merlin Rocha
- Postgraduate Program in Sciences (Biochemistry), Department of Biochemistry and Molecular Biology, UFPR, Curitiba, PR, Brazil
| | - Elizabeth Sousa Cunha
- Postgraduate Program in Sciences (Biochemistry), Department of Biochemistry and Molecular Biology, UFPR, Curitiba, PR, Brazil
| | - Glaucia Regina Martinez
- Postgraduate Program in Sciences (Biochemistry), Department of Biochemistry and Molecular Biology, UFPR, Curitiba, PR, Brazil.
| |
Collapse
|
2
|
Diabate M, Islam MM, Nagy G, Banerjee T, Dhar S, Smith N, Adamovich AI, Starita LM, Parvin JD. DNA repair function scores for 2172 variants in the BRCA1 amino-terminus. PLoS Genet 2023; 19:e1010739. [PMID: 37578980 PMCID: PMC10449183 DOI: 10.1371/journal.pgen.1010739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 08/24/2023] [Accepted: 07/16/2023] [Indexed: 08/16/2023] Open
Abstract
Single nucleotide variants are the most frequent type of sequence changes detected in the genome and these are frequently variants of uncertain significance (VUS). VUS are changes in DNA for which disease risk association is unknown. Thus, methods that classify the functional impact of a VUS can be used as evidence for variant interpretation. In the case of the breast and ovarian cancer specific tumor suppressor protein, BRCA1, pathogenic missense variants frequently score as loss of function in an assay for homology-directed repair (HDR) of DNA double-strand breaks. We previously published functional results using a multiplexed assay for 1056 amino acid substitutions residues 2-192 in the amino terminus of BRCA1. In this study, we have re-assessed the data from this multiplexed assay using an improved analysis pipeline. These new analysis methods yield functional scores for more variants in the first 192 amino acids of BRCA1, plus we report new results for BRCA1 amino acid residues 193-302. We now present the functional classification of 2172 BRCA1 variants in BRCA1 residues 2-302 using the multiplexed HDR assay. Comparison of the functional determinations of the missense variants with clinically known benign or pathogenic variants indicated 93% sensitivity and 100% specificity for this assay. The results from BRCA1 variants tested in this assay are a resource for clinical geneticists for evidence to evaluate VUS in BRCA1.
Collapse
Affiliation(s)
- Mariame Diabate
- The Ohio State University, Department of Biomedical Informatics, Columbus, Ohio, United States of America
- The Ohio State University Comprehensive Cancer Center, Columbus, Ohio, United States of America
| | - Muhtadi M. Islam
- The Ohio State University, Department of Biomedical Informatics, Columbus, Ohio, United States of America
- The Ohio State University Comprehensive Cancer Center, Columbus, Ohio, United States of America
| | - Gregory Nagy
- The Ohio State University, Department of Biomedical Informatics, Columbus, Ohio, United States of America
- The Ohio State University Comprehensive Cancer Center, Columbus, Ohio, United States of America
| | - Tapahsama Banerjee
- The Ohio State University, Department of Biomedical Informatics, Columbus, Ohio, United States of America
- The Ohio State University Comprehensive Cancer Center, Columbus, Ohio, United States of America
| | - Shruti Dhar
- The Ohio State University, Department of Biomedical Informatics, Columbus, Ohio, United States of America
- The Ohio State University Comprehensive Cancer Center, Columbus, Ohio, United States of America
| | - Nahum Smith
- The University of Washington, Department of Genome Sciences, Seattle, Washington, United States of America
- Brotman Baty Institute for Precision Medicine, Seattle, Washington, United States of America
| | - Aleksandra I. Adamovich
- The Ohio State University, Department of Biomedical Informatics, Columbus, Ohio, United States of America
- The Ohio State University Comprehensive Cancer Center, Columbus, Ohio, United States of America
| | - Lea M. Starita
- The University of Washington, Department of Genome Sciences, Seattle, Washington, United States of America
- Brotman Baty Institute for Precision Medicine, Seattle, Washington, United States of America
| | - Jeffrey D. Parvin
- The Ohio State University, Department of Biomedical Informatics, Columbus, Ohio, United States of America
- The Ohio State University Comprehensive Cancer Center, Columbus, Ohio, United States of America
| |
Collapse
|
3
|
Diabate M, Islam MM, Nagy G, Banerjee T, Dhar S, Smith N, Adamovich AI, Starita LM, Parvin JD. DNA Repair Function Scores for 2172 Variants in the BRCA1 Amino-Terminus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.10.536331. [PMID: 37090572 PMCID: PMC10120616 DOI: 10.1101/2023.04.10.536331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Single nucleotide variants are the most frequent type of sequence changes detected in the genome and these are frequently variants of uncertain significance (VUS). VUS are changes in DNA for which disease risk association is unknown. Thus, methods that classify the functional impact of a VUS can be used as evidence for variant interpretation. In the case of the breast and ovarian cancer specific tumor suppressor protein, BRCA1, pathogenic missense variants frequently score as loss of function in an assay for homology-directed repair (HDR) of DNA double-strand breaks. We previously published functional results using a multiplexed assay for 1056 amino acid substitutions residues 2-192 in the amino terminus of BRCA1. In this study, we have re-assessed the data from this multiplexed assay using an improved analysis pipeline. These new analysis methods yield functional scores for more variants in the first 192 amino acids of BRCA1, plus we report new results for BRCA1 amino acid residues 193-302. We now present the functional classification of 2172 BRCA1 variants in BRCA1 residues 2-302 using the multiplexed HDR assay. Comparison of the functional determinations of the missense variants with clinically known benign or pathogenic variants indicated 93% sensitivity and 100% specificity for this assay. The results from BRCA1 variants tested in this assay are a resource for clinical geneticists for evidence to evaluate VUS in BRCA1 . AUTHOR SUMMARY Most missense substitutions in BRCA1 are variants of unknown significance (VUS), and individuals with a VUS in BRCA1 cannot know from genetic information alone whether this variant predisposes to breast or ovarian cancer. We apply a multiplexed functional assay for homology directed repair of DNA double strand breaks to assess variant impact on this important BRCA1 protein function. We analyzed 2172 variants in the amino-terminus of BRCA1 and demonstrate that variants that are known as pathogenic have a loss of function in the DNA repair assay. Conversely, variants that are known to be benign are functionally normal in the multiplexed assay. We suggest that these functional determinations of BRCA1 variants can be used to augment the information that clinical cancer geneticists provide to patients who have a VUS in BRCA1 .
Collapse
Affiliation(s)
- Mariame Diabate
- The Ohio State University, Department of Biomedical Informatics, and The Ohio State University Comprehensive Center, Columbus, OH 43210
| | - Muhtadi M Islam
- The Ohio State University, Department of Biomedical Informatics, and The Ohio State University Comprehensive Center, Columbus, OH 43210
| | - Gregory Nagy
- The Ohio State University, Department of Biomedical Informatics, and The Ohio State University Comprehensive Center, Columbus, OH 43210
| | - Tapahsama Banerjee
- The Ohio State University, Department of Biomedical Informatics, and The Ohio State University Comprehensive Center, Columbus, OH 43210
| | - Shruti Dhar
- The Ohio State University, Department of Biomedical Informatics, and The Ohio State University Comprehensive Center, Columbus, OH 43210
| | - Nahum Smith
- The University of Washington, Department of Genome Sciences, Seattle, WA 98195
- Brotman Baty Institute for Precision Medicine, Seattle WA, 98195
| | - Aleksandra I Adamovich
- The Ohio State University, Department of Biomedical Informatics, and The Ohio State University Comprehensive Center, Columbus, OH 43210
| | - Lea M Starita
- The University of Washington, Department of Genome Sciences, Seattle, WA 98195
- Brotman Baty Institute for Precision Medicine, Seattle WA, 98195
| | - Jeffrey D Parvin
- The Ohio State University, Department of Biomedical Informatics, and The Ohio State University Comprehensive Center, Columbus, OH 43210
| |
Collapse
|
4
|
High-Resolution Crystal Structure of Muscle Phosphoglycerate Mutase Provides Insight into Its Nuclear Import and Role. Int J Mol Sci 2022; 23:ijms232113198. [DOI: 10.3390/ijms232113198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 10/25/2022] [Accepted: 10/27/2022] [Indexed: 11/16/2022] Open
Abstract
Phosphoglycerate mutase (PGAM) is a glycolytic enzyme converting 3-phosphoglycerate to 2-phosphoglycerate, which in mammalian cells is expressed in two isoforms: brain (PGAM1) and muscle (PGAM2). Recently, it was shown that besides its enzymatic function, PGAM2 can be imported to the cell nucleus where it co-localizes with the nucleoli. It was suggested that it functions there to stabilize the nucleolar structure, maintain mRNA expression, and assist in the assembly of new pre-ribosomal subunits. However, the precise mechanism by which the protein translocates to the nucleus is unknown. In this study, we present the first crystal structure of PGAM2, identify the residues involved in the nuclear localization of the protein and propose that PGAM contains a “quaternary nuclear localization sequence (NLS)”, i.e., one that consists of residues from different protein chains. Additionally, we identify potential interaction partners for PGAM2 in the nucleoli and demonstrate that 14-3-3ζ/δ is indeed an interaction partner of PGAM2 in the nucleus. We also present evidence that the insulin/IGF1–PI3K–Akt–mTOR signaling pathway is responsible for the nuclear localization of PGAM2.
Collapse
|
5
|
Importin alpha 1 is required for the nucleus entry of Fowl Adenovirus serotype 4 Fiber-1 protein. Vet Microbiol 2022; 266:109351. [PMID: 35121306 DOI: 10.1016/j.vetmic.2022.109351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 11/23/2022]
Abstract
Fiber-1 protein (F1) is the structural protein of Fowl Adenovirus serotype 4 (FAdV-4), which could recondite the receptors of host cytomembrane. In this study, we firstly determined that F1 protein located in nucleus of LMH cells after infection with FAdV-4. We additionally revealed that F1 protein had a classic NLS, and the NLS was required for F1 nucleus entry, which was intently associated to the 26th Pro in NLS. The time rule result indicated that some F1 proteins firstly positioned in the nucleus 6 h posttranfection, and it entirely located in the nucleus 12 h posttranfection, then it ordinarily placed in cytoplasm 18 h posttranfection by means of microscopic fluorescence observation and Western Blotting. Then after transfection with pCI-neo-flag-F1 or infection with FAdV-4, the importin alpha 1 was once investigated whether or not it was required for F1 protein nucleus entry through immunofluorescence and/or Co-IP, results demonstrated that the F1 protein and importin alpha 1 co-located in the nucleus 6 h and 12 h posttranfection. The tiers of F1 protein vicinity in nucleus have been additionally investigated after knockdown expression or overexpression of importin alpha 1, and the results further revealed that importin alpha 1 used to be required for F1 protein nucleus entry. Finally, the function of F1 protein nucleus entry was investigated by qPCR, RT-PCR and Western Blotting, and the results revealed that F1 protein nucleus location was conducive to the proliferation of FAdV-4. In summary, we firstly reveal that the F1 protein of FAdV-4 locates in nucleus infected with FAdV-4, and confirm that importin alpha 1 binds to the NLS of F1 protein to nucleus localization, which promotes the proliferation of FAdV-4.
Collapse
|
6
|
BRCA1 Mutation-Specific Responses to 53BP1 Loss-Induced Homologous Recombination and PARP Inhibitor Resistance. Cell Rep 2019; 24:3513-3527.e7. [PMID: 30257212 DOI: 10.1016/j.celrep.2018.08.086] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 08/01/2018] [Accepted: 08/29/2018] [Indexed: 12/21/2022] Open
Abstract
BRCA1 functions in homologous recombination (HR) both up- and downstream of DNA end resection. However, in cells with 53BP1 gene knockout (KO), BRCA1 is dispensable for the initiation of resection, but whether BRCA1 activity is entirely redundant after end resection is unclear. Here, we found that 53bp1 KO rescued the embryonic viability of a Brca1ΔC/ΔC mouse model that harbors a stop codon in the coiled-coil domain. However, Brca1ΔC/ΔC;53bp1-/- mice were susceptible to tumor formation, lacked Rad51 foci, and were sensitive to PARP inhibitor (PARPi) treatment, indicative of suboptimal HR. Furthermore, BRCA1 mutant cancer cell lines were dependent on truncated BRCA1 proteins that retained the ability to interact with PALB2 for 53BP1 KO induced RAD51 foci and PARPi resistance. Our data suggest that the overall efficiency of 53BP1 loss of function induced HR may be BRCA1 mutation dependent. In the setting of 53BP1 KO, hypomorphic BRCA1 proteins are active downstream of end resection, promoting RAD51 loading and PARPi resistance.
Collapse
|
7
|
Freeman BT, Sokolowski M, Roy-Engel AM, Smither ME, Belancio VP. Identification of charged amino acids required for nuclear localization of human L1 ORF1 protein. Mob DNA 2019; 10:20. [PMID: 31080522 PMCID: PMC6501352 DOI: 10.1186/s13100-019-0159-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Accepted: 04/10/2019] [Indexed: 01/10/2023] Open
Abstract
Background Long Interspersed Element 1 (LINE-1) is a retrotransposon that is present in 500,000 copies in the human genome. Along with Alu and SVA elements, these three retrotransposons account for more than a third of the human genome sequence. These mobile elements are able to copy themselves within the genome via an RNA intermediate, a process that can promote genome instability. LINE-1 encodes two proteins, ORF1p and ORF2p. Association of ORF1p, ORF2p and a full-length L1 mRNA in a ribonucleoprotein (RNP) particle, L1 RNP, is required for L1 retrotransposition. Previous studies have suggested that fusion of a tag to L1 proteins can interfere with L1 retrotransposition. Results Using antibodies detecting untagged human ORF1p, western blot analysis and manipulation of ORF1 sequence and length, we have identified a set of charged amino acids in the C-terminal region of ORF1p that are important in determining its subcellular localization. Mutation of 7 non-identical lysine residues is sufficient to make the resulting ORF1p to be predominantly cytoplasmic, demonstrating intrinsic redundancy of this requirement. These residues are also necessary for ORF1p to retain its association with KPNA2 nuclear pore protein. We demonstrate that this interaction is significantly reduced by RNase treatment. Using co-IP, we have also determined that human ORF1p associates with all members of the KPNA subfamily. Conclusions The prediction of NLS sequences suggested that specific sequences within ORF1p could be responsible for its subcellular localization by interacting with nuclear binding proteins. We have found that multiple charged amino acids in the C-terminus of ORF1p are involved in ORF1 subcellular localization and interaction with KPNA2 nuclear pore protein. Our data demonstrate that different amino acids can be mutated to have the same phenotypic effect on ORF1p subcellular localization, demonstrating that the net number of charged residues or protein structure, rather than their specific location, is important for the ORF1p nuclear localization. We also identified that human ORF1p interacts with all members of the KPNA family of proteins and that multiple KPNA family genes are expressed in human cell lines. Electronic supplementary material The online version of this article (10.1186/s13100-019-0159-2) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- B T Freeman
- 1Department of Structural and Cellular Biology, Tulane University School of Medicine, Tulane Cancer Center, Tulane Center for Aging, New Orleans, LA 70112 USA
| | - M Sokolowski
- 1Department of Structural and Cellular Biology, Tulane University School of Medicine, Tulane Cancer Center, Tulane Center for Aging, New Orleans, LA 70112 USA
| | - A M Roy-Engel
- 2Department of Epidemiology, School of Public Health and Tropical Medicine, Tulane Cancer Center, Tulane University, New Orleans, Louisiana 70112 USA
| | - M E Smither
- 1Department of Structural and Cellular Biology, Tulane University School of Medicine, Tulane Cancer Center, Tulane Center for Aging, New Orleans, LA 70112 USA
| | - V P Belancio
- 1Department of Structural and Cellular Biology, Tulane University School of Medicine, Tulane Cancer Center, Tulane Center for Aging, New Orleans, LA 70112 USA
| |
Collapse
|
8
|
Langerud J, Jarhelle E, Van Ghelue M, Ariansen SL, Iversen N. Trans-activation-based risk assessment of BRCA1 BRCT variants with unknown clinical significance. Hum Genomics 2018; 12:51. [PMID: 30458859 PMCID: PMC6247502 DOI: 10.1186/s40246-018-0183-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 11/08/2018] [Indexed: 11/30/2022] Open
Abstract
Background Deleterious variants in the tumour suppressor BRCA1 are known to cause hereditary breast and ovarian cancer syndrome (HBOC). Missense variants in BRCA1 pose a challenge in clinical care, as their effect on protein functionality often remains unknown. Many of the pathogenic missense variants found in BRCA1 are located in the BRCA1 C-terminal (BRCT) domains, domains that are known to be vital for key functions such as homologous recombination repair, protein-protein interactions and trans-activation (TA). We investigated the TA activity of 12 BRCA1 variants of unknown clinical significance (VUSs) located in the BRCT domains to aid in the classification of these variants. Results Twelve BRCA1 VUSs were investigated using a modified version of the dual luciferase TA activity assay (TA assay) that yielded increased sensitivity and sample throughput. Variants were classified according to American College of Medical Genetics and Genomics (ACMG) criteria using TA assay results and available data. In combining our TA-assay results and available data, in accordance with the ACMG guidelines for variant classification, we proposed the following variant classifications: c.5100A>G, c.5326C>T, c.5348T>C and c.5477A>T as likely benign (class 2) variants. c.5075A>C, c.5116G>A and c.5513T>G were likely pathogenic (class 4), whereas c.5096G>A likely represents a likely pathogenic variant with moderate penetrance. Variants c.5123C>T, c.5125G>A, c.5131A>C and c.5504G>A remained classified as VUSs (class 3). Conclusions The modified TA assay provides efficient risk assessment of rare missense variants found in the BRCA1 BRCT-domains. We also report that increased post-transfection incubation time yielded a significant increase in TA assay sensitivity. Electronic supplementary material The online version of this article (10.1186/s40246-018-0183-1) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Jonas Langerud
- Department of Medical Genetics, Oslo University Hospital, Oslo, Norway
| | - Elisabeth Jarhelle
- Department of Medical Genetics, Division of Child and Adolescent Health, University Hospital of North Norway, Tromsø, Norway
| | - Marijke Van Ghelue
- Department of Medical Genetics, Division of Child and Adolescent Health, University Hospital of North Norway, Tromsø, Norway
| | | | - Nina Iversen
- Department of Medical Genetics, Oslo University Hospital, Oslo, Norway.
| |
Collapse
|
9
|
Wu ZC, Zhang RH, Li YM, Shao DH, Chen H, Jiang SJ, Ma ZY, Wang X. C-terminal 20 residues of ORF3 protein of duck circovirus genotype 2 regulates the nuclear localization and inhibits apoptotic activity of ORF3 protein. Vet Microbiol 2017; 214:21-27. [PMID: 29408028 DOI: 10.1016/j.vetmic.2017.12.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 12/02/2017] [Accepted: 12/04/2017] [Indexed: 10/18/2022]
Abstract
Duck circovirus (DuCV) is divided into genotypes 1 and 2. The DuCV ORF3 protein is a newly identified viral protein with apoptotic activity. In this study, the differences in the gene sequences, subcellular localization, and apoptotic activities of the ORF3 proteins of DuCV genotypes 1 and 2 were analyzed. A T-to-A point mutation at nucleotide 236 (T236A) in the ORF3 gene sequence of DuCV genotype 1 was observed, which generates a premature stop codon (TAG) and resulted in a truncated ORF3 protein. The ORF3 protein of DuCV genotype 2 is 20 amino acids longer at its C-terminus than the truncated ORF3 protein of genotype 1. A variant monopartite-type nuclear localization signal (RRLRTCNCRACRTLK) was identified within the C-terminal region of the ORF3 protein of DuCV genotype 2, which is essential for the nuclear localization of the protein. The 20 C-terminal residues of the DuCV genotype 2 ORF3 protein also inhibits the apoptotic activity of the protein. Our findings provide insight into the biological and functional characteristics of the DuCV ORF3 protein.
Collapse
Affiliation(s)
- Zhuan-Chang Wu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 518, Ziyue road, Shanghai, 200241, PR China
| | - Rui-Hua Zhang
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Shandong Agricultural University, Taian, Shandong, 271018, PR China
| | - Yu-Ming Li
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 518, Ziyue road, Shanghai, 200241, PR China
| | - Dong-Hua Shao
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 518, Ziyue road, Shanghai, 200241, PR China
| | - Hua Chen
- College of Agriculture and Forestry Science, Linyi University, Shuangling Road, Linyi City, Shandong, 276005, PR China
| | - Shi-Jin Jiang
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Shandong Agricultural University, Taian, Shandong, 271018, PR China
| | - Zhi-Yong Ma
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 518, Ziyue road, Shanghai, 200241, PR China.
| | - Xin Wang
- College of Agriculture and Forestry Science, Linyi University, Shuangling Road, Linyi City, Shandong, 276005, PR China.
| |
Collapse
|
10
|
Novel Nine-Exon AR Transcripts (Exon 1/Exon 1b/Exons 2-8) in Normal and Cancerous Breast and Prostate Cells. Int J Mol Sci 2016; 18:ijms18010040. [PMID: 28035996 PMCID: PMC5297675 DOI: 10.3390/ijms18010040] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 12/08/2016] [Accepted: 12/20/2016] [Indexed: 12/12/2022] Open
Abstract
Nearly 20 different transcripts of the human androgen receptor (AR) are reported with two currently listed as Refseq isoforms in the NCBI database. Isoform 1 encodes wild-type AR (type 1 AR) and isoform 2 encodes the variant AR45 (type 2 AR). Both variants contain eight exons: they share common exons 2-8 but differ in exon 1 with the canonical exon 1 in isoform 1 and the variant exon 1b in isoform 2. Splicing of exon 1 or exon 1b is reported to be mutually exclusive. In this study, we identified a novel exon 1b (1b/TAG) that contains an additional TAG trinucleotide upstream of exon 1b. Moreover, we identified AR transcripts in both normal and cancerous breast and prostate cells that contained either exon 1b or 1b/TAG spliced between the canonical exon 1 and exon 2, generating nine-exon AR transcripts that we have named isoforms 3a and 3b. The proteins encoded by these new AR variants could regulate androgen-responsive reporters in breast and prostate cancer cells under androgen-depleted conditions. Analysis of type 3 AR-GFP fusion proteins showed partial nuclear localization in PC3 cells under androgen-depleted conditions, supporting androgen-independent activation of the AR. Type 3 AR proteins inhibited androgen-induced growth of LNCaP cells. Microarray analysis identified a small set of type 3a AR target genes in LNCaP cells, including genes known to modulate growth and proliferation of prostate cancer (PCGEM1, PEG3, EPHA3, and EFNB2) or other types of human cancers (TOX3, ST8SIA4, and SLITRK3), and genes that are diagnostic/prognostic biomarkers of prostate cancer (GRINA3, and BCHE).
Collapse
|
11
|
Duan J, Tang Z, Mu H, Zhang G. Nuclear import of prototype foamy virus transactivator Bel1 is mediated by KPNA1, KPNA6 and KPNA7. Int J Mol Med 2016; 38:399-406. [PMID: 27277550 PMCID: PMC4935454 DOI: 10.3892/ijmm.2016.2635] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 05/31/2016] [Indexed: 01/01/2023] Open
Abstract
Bel1, a transactivator of the prototype foamy virus (PFV), plays pivotal roles in the replication of PFV. Previous studies have demonstrated that Bel1 bears a nuclear localization signal (NLS); however, its amino acid sequence remains unclear and the corresponding adaptor importins have not yet been identified. In this study, we inserted various fragments of Bel1 into an EGFP-GST fusion protein and investigated their subcellular localization by fluorescence microscopy. We found that the 215PRQKRPR221 fragment, which accords with the consensus sequence K(K/R)X(K/R) of the monopartite NLS, directed the nuclear translocation of Bel1. Point mutation experiments revealed that K218, R219 and R221 were essential for the nuclear localization of Bel1. The results of GST pull-down assay revealed that the Bel1 peptide 215-221, which bears the NLS, interacted with the nucleocytoplasmic transport receptors, karyopherin alpha 1 (importin alpha 5) (KPNA1), karyopherin alpha 6 (importin alpha 7) (KPNA6) and karyopherin alpha 7 (importin alpha 8) (KPNA7). Finally, in vitro nuclear import assays demonstrated that KPNA1, KPNA6 or KPNA7, along with other necessary nuclear factors, caused Bel1 to localize to the nucleus. Thus, the findings of our study indicate that KPNA1, KPNA6 and KPNA7 are involved in Bel1 nuclear distribution.
Collapse
Affiliation(s)
- Jihui Duan
- Clinical Laboratory, Tianjin First Center Hospital, Tianjin 300192, P.R. China
| | - Zhiqin Tang
- Clinical Laboratory, Tianjin First Center Hospital, Tianjin 300192, P.R. China
| | - Hong Mu
- Clinical Laboratory, Tianjin First Center Hospital, Tianjin 300192, P.R. China
| | - Guojun Zhang
- Clinical Laboratory, Tianjin First Center Hospital, Tianjin 300192, P.R. China
| |
Collapse
|
12
|
Wiener D, Gajardo-Meneses P, Ortega-Hernández V, Herrera-Cares C, Díaz S, Fernández W, Cornejo V, Gamboa J, Tapia T, Alvarez C, Carvallo P. BRCA1 and BARD1 colocalize mainly in the cytoplasm of breast cancer tumors, and their isoforms show differential expression. Breast Cancer Res Treat 2015; 153:669-78. [PMID: 26395808 DOI: 10.1007/s10549-015-3575-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 09/15/2015] [Indexed: 12/13/2022]
Abstract
BRCA1 has been found to be absent or miss localized in the cytoplasm in a relevant proportion of breast cancer tumors with no germline mutations. BRCA1 main function is in the nucleus, and its interaction with BARD1 is relevant for its nuclear translocation and retention. Our aim was to analyze the sub-cellular localization of BRCA1 and BARD1 in breast cancer tumors, and determine the level of expression of their splice variants BRCA1-Δ11q and BARD1-α and BARD1-β. BRCA1 and BARD1 expressions were performed by immunohistochemistry and immunofluorescence in 103 breast cancer tumors. Colocalization was determined by confocal microscopy. Transcript variants were determined by qRT-PCR. We found BRCA1 localized in the cytoplasm with BARD1 in 51.4 % of tumors. An exclusive nuclear localization of both proteins was observed in 7/103 tumors (6.8 %). Indeed, these tumors displayed an apparent nucleolar colocalization of BARD1 and BRCA1. In relation to splice variants, there is a tendency to an overexpression of BARD1-α mRNA (30 % of tumors) and a decreased expression of BARD1-β (41 %). BRCA1 full-length was downregulated in 63 % of tumors, and 37 % showed BRCA1-Δ11q variant overexpressed. Our findings contribute to a better understanding of the expression and sub-cellular localization of BRCA1 in breast cancer tumors. Interaction of BRCA1 and BARD1 seems to be not affected in 58.2 % of tumors, which showed colocalization of both proteins. The absence of BRCA1 in 41 % of tumors reveals a BRCAness phenotype, constituting an excellent marker for therapy sensitivity, to platinum drugs or PARP inhibitors.
Collapse
Affiliation(s)
- David Wiener
- Laboratory of Human Molecular Genetics, Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Portugal 49 3rd floor, Postal code 8330025, Santiago, Chile
| | - Patricia Gajardo-Meneses
- Laboratory of Human Molecular Genetics, Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Portugal 49 3rd floor, Postal code 8330025, Santiago, Chile
| | - Victoria Ortega-Hernández
- Laboratory of Human Molecular Genetics, Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Portugal 49 3rd floor, Postal code 8330025, Santiago, Chile
| | - Cristóbal Herrera-Cares
- Laboratory of Human Molecular Genetics, Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Portugal 49 3rd floor, Postal code 8330025, Santiago, Chile
| | - Sebastián Díaz
- Laboratory of Human Molecular Genetics, Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Portugal 49 3rd floor, Postal code 8330025, Santiago, Chile
| | - Wanda Fernández
- Unidad de Anatomía Patológica, Hospital Clínico San Borja Arriarán, Santiago, Chile
| | - Valeria Cornejo
- Unidad de Anatomía Patológica, Hospital Clínico San Borja Arriarán, Santiago, Chile
| | - Jorge Gamboa
- Unidad de Patología Mamaria, Hospital Clínico San Borja Arriarán, Santiago, Chile
| | - Teresa Tapia
- Laboratory of Human Molecular Genetics, Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Portugal 49 3rd floor, Postal code 8330025, Santiago, Chile
| | - Carolina Alvarez
- Laboratory of Human Molecular Genetics, Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Portugal 49 3rd floor, Postal code 8330025, Santiago, Chile
| | - Pilar Carvallo
- Laboratory of Human Molecular Genetics, Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Portugal 49 3rd floor, Postal code 8330025, Santiago, Chile.
| |
Collapse
|
13
|
Salemi LM, Loureiro SO, Schild-Poulter C. Characterization of RanBPM molecular determinants that control its subcellular localization. PLoS One 2015; 10:e0117655. [PMID: 25659156 PMCID: PMC4319831 DOI: 10.1371/journal.pone.0117655] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 12/30/2014] [Indexed: 12/14/2022] Open
Abstract
RanBPM/RanBP9 is a ubiquitous, nucleocytoplasmic protein that is part of an evolutionary conserved E3 ubiquitin ligase complex whose function and targets in mammals are still unknown. RanBPM itself has been implicated in various cellular processes that involve both nuclear and cytoplasmic functions. However, to date, little is known about how RanBPM subcellular localization is regulated. We have conducted a systematic analysis of RanBPM regions that control its subcellular localization using RanBPM shRNA cells to examine ectopic RanBPM mutant subcellular localization without interference from the endogenously expressed protein. We show that several domains and motifs regulate RanBPM nuclear and cytoplasmic localization. In particular, RanBPM comprises two motifs that can confer nuclear localization, one proline/glutamine-rich motif in the extreme N-terminus which has a dominant effect on RanBPM localization, and a second motif in the C-terminus which minimally contributes to RanBPM nuclear targeting. We also identified a nuclear export signal (NES) which mutation prevented RanBPM accumulation in the cytoplasm. Likewise, deletion of the central RanBPM conserved domains (SPRY and LisH/CTLH) resulted in the relocalization of RanBPM to the nucleus, suggesting that RanBPM cytoplasmic localization is also conferred by protein-protein interactions that promote its cytoplasmic retention. Indeed we found that in the cytoplasm, RanBPM partially colocalizes with microtubules and associates with α-tubulin. Finally, in the nucleus, a significant fraction of RanBPM is associated with chromatin. Altogether, these analyses reveal that RanBPM subcellular localization results from the combined effects of several elements that either confer direct transport through the nucleocytoplasmic transport machinery or regulate it indirectly, likely through interactions with other proteins and by intramolecular folding.
Collapse
Affiliation(s)
- Louisa M. Salemi
- Robarts Research Institute and Department of Biochemistry, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Sandra O. Loureiro
- Robarts Research Institute and Department of Biochemistry, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Caroline Schild-Poulter
- Robarts Research Institute and Department of Biochemistry, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada
- * E-mail:
| |
Collapse
|
14
|
Decay of γ-H2AX foci correlates with potentially lethal damage repair and P53 status in human colorectal carcinoma cells. Cell Mol Biol Lett 2013; 19:37-51. [PMID: 24363165 PMCID: PMC6275741 DOI: 10.2478/s11658-013-0113-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 12/18/2013] [Indexed: 11/20/2022] Open
Abstract
The influence of p53 status on potentially lethal damage repair (PLDR) and DNA double-strand break (DSB) repair was studied in two isogenic human colorectal carcinoma cell lines: RKO (p53 wild-type) and RC10.1 (p53 null). They were treated with different doses of ionizing radiation, and survival and the induction of DNA-DSB were studied. PLDR was determined by using clonogenic assays and then comparing the survival of cells plated immediately with the survival of cells plated 24 h after irradiation. Doses varied from 0 to 8 Gy. Survival curves were analyzed using the linear-quadratic formula: S(D)/S(0) = exp-(αD+βD2). The γ-H2AX foci assay was used to study DNA DSB kinetics. Cells were irradiated with single doses of 0, 0.5, 1 and 2 Gy. Foci levels were studied in non-irradiated control cells and 30 min and 24 h after irradiation. Irradiation was performed with gamma rays from a 137Cs source, with a dose rate of 0.5 Gy/min. The RKO cells show higher survival rates after delayed plating than after immediate plating, while no such difference was found for the RC10.1 cells. Functional p53 seems to be a relevant characteristic regarding PLDR for cell survival. Decay of γ-H2AX foci after exposure to ionizing radiation is associated with DSB repair. More residual foci are observed in RC10.1 than in RKO, indicating that decay of γ-H2AX foci correlates with p53 functionality and PLDR in RKO cells.
Collapse
|
15
|
Chakraborty A, Katarkar A, Chaudhuri K, Mukhopadhyay A, Basak J. Detection of a novel mutation in exon 20 of the BRCA1 gene. Cell Mol Biol Lett 2013; 18:631-8. [PMID: 24297685 PMCID: PMC6275959 DOI: 10.2478/s11658-013-0110-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Accepted: 11/27/2013] [Indexed: 11/20/2022] Open
Abstract
Hereditary breast cancer constitutes 5-10% of all breast cancer cases. Inherited mutations in the BRCA1 and BRCA2 tumor-suppressor genes account for the majority of hereditary breast cancer cases. The BRCA1 C-terminal region (BRCT) has a functional duplicated globular domain, which helps with DNA damage repair and cell cycle checkpoint protein control. More than 100 distinct BRCA1 missense variants with structural and functional effects have been documented within the BRCT domain. Interpreting the results of mutation screening of tumor-suppressor genes that can have high-risk susceptibility mutations is increasingly important in clinical practice. This study includes a novel mutation, p.His1746 Pro (c.5237A>C), which was found in BRCA1 exon 20 of a breast cancer patient. In silico analysis suggests that this mutation could alter the stability and orientation of the BRCT domain and the differential binding of the BACH1 substrate.
Collapse
Affiliation(s)
- Abhijit Chakraborty
- Department of Molecular Biology, Netaji Subhas Chandra Bose Cancer Research Institute (NCRI), Kolkata, India
| | - Atul Katarkar
- Molecular & Human Genetics Division, Indian Institute of Chemical Biology (IICB), Kolkata, India
| | - Keya Chaudhuri
- Molecular & Human Genetics Division, Indian Institute of Chemical Biology (IICB), Kolkata, India
| | - Ashis Mukhopadhyay
- Department of Oncology, Netaji Subhas Chandra Bose Cancer Research Institute (NCRI), Kolkata, India
| | - Jayasri Basak
- Department of Molecular Biology, Netaji Subhas Chandra Bose Cancer Research Institute (NCRI), Kolkata, India
| |
Collapse
|