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Xia X. Multiple regulatory mechanisms for pH homeostasis in the gastric pathogen, Helicobacter pylori. ADVANCES IN GENETICS 2022; 109:39-69. [PMID: 36334916 DOI: 10.1016/bs.adgen.2022.07.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Acid-resistance in gastric pathogen Helicobacter pylori requires the coordination of four essential processes to regulate urease activity. Firstly, urease expression above a base level needs to be finely tuned at different ambient pH. Secondly, as nickel is needed to activate urease, nickel homeostasis needs to be maintained by proteins that import and export nickel ions, and sequester, store and release nickel when needed. Thirdly, urease accessary proteins that activate urease activity by nickel insertion need to be expressed. Finally, a reliable source of urea needs to be maintained by both intrinsic and extrinsic sources of urea. Two-component systems (arsRS and flgRS), as well as a nickel response regulator (NikR), sense the change in pH and act on a variety of genes to accomplish the function of acid resistance without causing cellular overalkalization and nickel toxicity. Nickel storage proteins also feature built-in switches to store nickel at neutral pH and release nickel at low pH. This review summarizes the current status of H. pylori research and highlights a number of hypotheses that need to be tested.
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Affiliation(s)
- Xuhua Xia
- Department of Biology, University of Ottawa, Ottawa, Canada; Ottawa Institute of Systems Biology, Ottawa, Canada.
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Svetec Miklenić M, Svetec IK. Palindromes in DNA-A Risk for Genome Stability and Implications in Cancer. Int J Mol Sci 2021; 22:2840. [PMID: 33799581 PMCID: PMC7999016 DOI: 10.3390/ijms22062840] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 03/04/2021] [Accepted: 03/08/2021] [Indexed: 02/07/2023] Open
Abstract
A palindrome in DNA consists of two closely spaced or adjacent inverted repeats. Certain palindromes have important biological functions as parts of various cis-acting elements and protein binding sites. However, many palindromes are known as fragile sites in the genome, sites prone to chromosome breakage which can lead to various genetic rearrangements or even cell death. The ability of certain palindromes to initiate genetic recombination lies in their ability to form secondary structures in DNA which can cause replication stalling and double-strand breaks. Given their recombinogenic nature, it is not surprising that palindromes in the human genome are involved in genetic rearrangements in cancer cells as well as other known recurrent translocations and deletions associated with certain syndromes in humans. Here, we bring an overview of current understanding and knowledge on molecular mechanisms of palindrome recombinogenicity and discuss possible implications of DNA palindromes in carcinogenesis. Furthermore, we overview the data on known palindromic sequences in the human genome and efforts to estimate their number and distribution, as well as underlying mechanisms of genetic rearrangements specific palindromic sequences cause.
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Affiliation(s)
| | - Ivan Krešimir Svetec
- Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, 10000 Zagreb, Croatia;
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A reference catalog of DNA palindromes in the human genome and their variations in 1000 Genomes. Hum Genome Var 2020; 7:40. [PMID: 33298903 PMCID: PMC7680136 DOI: 10.1038/s41439-020-00127-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 05/24/2020] [Accepted: 06/08/2020] [Indexed: 02/07/2023] Open
Abstract
A palindrome in DNA is like a palindrome in language, but when read backwards, it is a complement of the forward sequence; effectively, the two halves of a sequence complement each other from its midpoint like in a double strand of DNA. Palindromes are distributed throughout the human genome and play significant roles in gene expression and regulation. Palindromic mutations are linked to many human diseases, such as neuronal disorders, mental retardation, and various cancers. In this work, we computed and analyzed the palindromic sequences in the human genome and studied their conservation in personal genomes using 1000 Genomes data. We found that ~30% of the palindromes exhibit variation, some of which are caused by rare variants. The analysis of disease/trait-associated single-nucleotide polymorphisms in palindromic regions showed that disease-associated risk variants are 14 times more likely to be present in palindromic regions than in other regions. The catalog of palindromes in the reference genome and 1000 Genomes is being made available here with details on their variations in each individual genome to serve as a resource for future and retrospective whole-genome studies identifying statistically significant palindrome variations associated with diseases or traits and their roles in disease mechanisms.
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Shi W, Massaia A, Louzada S, Handsaker J, Chow W, McCarthy S, Collins J, Hallast P, Howe K, Church DM, Yang F, Xue Y, Tyler-Smith C. Birth, expansion, and death of VCY-containing palindromes on the human Y chromosome. Genome Biol 2019; 20:207. [PMID: 31610793 PMCID: PMC6790999 DOI: 10.1186/s13059-019-1816-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 09/04/2019] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Large palindromes (inverted repeats) make up substantial proportions of mammalian sex chromosomes, often contain genes, and have high rates of structural variation arising via ectopic recombination. As a result, they underlie many genomic disorders. Maintenance of the palindromic structure by gene conversion between the arms has been documented, but over longer time periods, palindromes are remarkably labile. Mechanisms of origin and loss of palindromes have, however, received little attention. RESULTS Here, we use fiber-FISH, 10x Genomics Linked-Read sequencing, and breakpoint PCR sequencing to characterize the structural variation of the P8 palindrome on the human Y chromosome, which contains two copies of the VCY (Variable Charge Y) gene. We find a deletion of almost an entire arm of the palindrome, leading to death of the palindrome, a size increase by recruitment of adjacent sequence, and other complex changes including the formation of an entire new palindrome nearby. Together, these changes are found in ~ 1% of men, and we can assign likely molecular mechanisms to these mutational events. As a result, healthy men can have 1-4 copies of VCY. CONCLUSIONS Gross changes, especially duplications, in palindrome structure can be relatively frequent and facilitate the evolution of sex chromosomes in humans, and potentially also in other mammalian species.
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Affiliation(s)
- Wentao Shi
- The Wellcome Sanger Institute, Hinxton, Cambridgeshire, CB10 1SA, UK
- Department of Genetics, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, 300070, China
| | - Andrea Massaia
- The Wellcome Sanger Institute, Hinxton, Cambridgeshire, CB10 1SA, UK
- Present address: National Heart and Lung Institute, Imperial College London, London, SW7 2AZ, UK
| | - Sandra Louzada
- The Wellcome Sanger Institute, Hinxton, Cambridgeshire, CB10 1SA, UK
| | - Juliet Handsaker
- The Wellcome Sanger Institute, Hinxton, Cambridgeshire, CB10 1SA, UK
| | - William Chow
- The Wellcome Sanger Institute, Hinxton, Cambridgeshire, CB10 1SA, UK
| | - Shane McCarthy
- The Wellcome Sanger Institute, Hinxton, Cambridgeshire, CB10 1SA, UK
- Present address: Department of Genetics, University of Cambridge, Cambridge, CB2 3EH, UK
| | - Joanna Collins
- The Wellcome Sanger Institute, Hinxton, Cambridgeshire, CB10 1SA, UK
| | - Pille Hallast
- The Wellcome Sanger Institute, Hinxton, Cambridgeshire, CB10 1SA, UK
- Institute of Biomedicine and Translational Medicine, University of Tartu, 51011, Tartu, Estonia
| | - Kerstin Howe
- The Wellcome Sanger Institute, Hinxton, Cambridgeshire, CB10 1SA, UK
| | - Deanna M Church
- 10x Genomics, 7068 Koll Center Parkway, Suite 401, Pleasanton, CA, 94566, USA
- Present address: Inscripta Inc., 5500 Central Avenue #220, Boulder, CO, 80301, USA
| | - Fengtang Yang
- The Wellcome Sanger Institute, Hinxton, Cambridgeshire, CB10 1SA, UK
| | - Yali Xue
- The Wellcome Sanger Institute, Hinxton, Cambridgeshire, CB10 1SA, UK.
| | - Chris Tyler-Smith
- The Wellcome Sanger Institute, Hinxton, Cambridgeshire, CB10 1SA, UK.
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Schönbach C, Verma C, Wee LJK, Bond PJ, Ranganathan S. 2016 update on APBioNet's annual international conference on bioinformatics (InCoB). BMC Genomics 2016; 17:1036. [PMID: 28155656 PMCID: PMC5259860 DOI: 10.1186/s12864-016-3362-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
InCoB became since its inception in 2002 one of the largest annual bioinformatics conferences in the Asia-Pacific region with attendance ranging between 150 and 250 delegates depending on the venue location. InCoB 2016 in Singapore was attended by almost 220 delegates. This year, sessions on structural bioinformatics, sequence and sequencing, and next-generation sequencing fielded the highest number of oral presentation. Forty-four out 96 oral presentations were associated with an accepted manuscript in supplemental issues of BMC Bioinformatics, BMC Genomics, BMC Medical Genomics or BMC Systems Biology. Articles with a genomics focus are reviewed in this editorial. Next year's InCoB will be held in Shenzen, China from September 20 to 22, 2017.
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Affiliation(s)
- Christian Schönbach
- International Research Center for Medical Sciences, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, 860-0811 Japan
| | - Chandra Verma
- Bioinformatics Institute, Agency for Science, Technology and Research (A∗STAR), Singapore, 138671 Singapore
| | - Lawrence Jin Kiat Wee
- Institute for Infocomm Research, Agency for Science, Technology and Research (A*STAR), Singapore, 138632 Singapore
| | - Peter John Bond
- Bioinformatics Institute, Agency for Science, Technology and Research (A∗STAR), Singapore, 138671 Singapore
| | - Shoba Ranganathan
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, NSW 2109 Australia
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