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Xing Z, Li Y, Cortes-Gomez E, Jiang X, Gao S, Pao A, Shan J, Song Y, Perez A, Yu T, Highsmith MR, Boadu F, Conroy JM, Singh PK, Bakin AV, Cheng J, Duan Z, Wang J, Liu S, Tycko B, Yu YE. Dissection of a Down syndrome-associated trisomy to separate the gene dosage-dependent and -independent effects of an extra chromosome. Hum Mol Genet 2023; 32:2205-2218. [PMID: 37014740 PMCID: PMC10281752 DOI: 10.1093/hmg/ddad056] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 02/13/2023] [Accepted: 03/27/2023] [Indexed: 04/05/2023] Open
Abstract
As an aneuploidy, trisomy is associated with mammalian embryonic and postnatal abnormalities. Understanding the underlying mechanisms involved in mutant phenotypes is broadly important and may lead to new strategies to treat clinical manifestations in individuals with trisomies, such as trisomy 21 [Down syndrome (DS)]. Although increased gene dosage effects because of a trisomy may account for the mutant phenotypes, there is also the possibility that phenotypic consequences of a trisomy can arise because of the presence of a freely segregating extra chromosome with its own centromere, i.e. a 'free trisomy' independent of gene dosage effects. Presently, there are no reports of attempts to functionally separate these two types of effects in mammals. To fill this gap, here we describe a strategy that employed two new mouse models of DS, Ts65Dn;Df(17)2Yey/+ and Dp(16)1Yey/Df(16)8Yey. Both models carry triplications of the same 103 human chromosome 21 gene orthologs; however, only Ts65Dn;Df(17)2Yey/+ mice carry a free trisomy. Comparison of these models revealed the gene dosage-independent impacts of an extra chromosome at the phenotypic and molecular levels for the first time. They are reflected by impairments of Ts65Dn;Df(17)2Yey/+ males in T-maze tests when compared with Dp(16)1Yey/Df(16)8Yey males. Results from the transcriptomic analysis suggest the extra chromosome plays a major role in trisomy-associated expression alterations of disomic genes beyond gene dosage effects. This model system can now be used to deepen our mechanistic understanding of this common human aneuploidy and obtain new insights into the effects of free trisomies in other human diseases such as cancers.
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Affiliation(s)
- Zhuo Xing
- The Children’s Guild Foundation Down Syndrome Research Program, Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Yichen Li
- The Children’s Guild Foundation Down Syndrome Research Program, Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Eduardo Cortes-Gomez
- Department of Biostatistics and Bioinformatics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Xiaoling Jiang
- The Children’s Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, Zhejiang, China
| | - Shuang Gao
- Department of Biostatistics and Bioinformatics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
- Bioinformatics, OmniSeq Inc., Buffalo, NY, USA
| | - Annie Pao
- The Children’s Guild Foundation Down Syndrome Research Program, Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Jidong Shan
- Molecular Cytogenetics Core, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Yinghui Song
- Molecular Cytogenetics Core, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Amanda Perez
- Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Tao Yu
- The Children’s Guild Foundation Down Syndrome Research Program, Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Max R Highsmith
- Department of Electric Engineering and Computer Science, University of Missouri, Columbia, MO, USA
| | - Frimpong Boadu
- Department of Electric Engineering and Computer Science, University of Missouri, Columbia, MO, USA
| | - Jeffrey M Conroy
- Research and Development, OmniSeq Inc., Buffalo, NY, USA
- Research Support Services, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Prashant K Singh
- Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Andrei V Bakin
- Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Jianlin Cheng
- Department of Electric Engineering and Computer Science, University of Missouri, Columbia, MO, USA
| | - Zhijun Duan
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
- Division of Hematology, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Jianmin Wang
- Department of Biostatistics and Bioinformatics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Song Liu
- Department of Biostatistics and Bioinformatics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Benjamin Tycko
- Hackensack-Meridian Health Center for Discovery and Innovation, Nutley, NJ, USA
- John Theurer Cancer Center, Hackensack University Medical Center, Hackensack, NJ, USA
| | - Y Eugene Yu
- The Children’s Guild Foundation Down Syndrome Research Program, Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
- Genetics, Genomics and Bioinformatics Program, State University of New York at Buffalo, Buffalo, NY, USA
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Flachs P, Mihola O, Šimeček P, Gregorová S, Schimenti JC, Matsui Y, Baudat F, de Massy B, Piálek J, Forejt J, Trachtulec Z. Interallelic and intergenic incompatibilities of the Prdm9 (Hst1) gene in mouse hybrid sterility. PLoS Genet 2012; 8:e1003044. [PMID: 23133405 PMCID: PMC3486856 DOI: 10.1371/journal.pgen.1003044] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Accepted: 09/07/2012] [Indexed: 11/18/2022] Open
Abstract
The Dobzhansky-Muller model of incompatibilities explains reproductive isolation between species by incorrect epistatic interactions. Although the mechanisms of speciation are of great interest, no incompatibility has been characterized at the gene level in mammals. The Hybrid sterility 1 gene (Hst1) participates in the arrest of meiosis in F1 males of certain strains from two Mus musculus subspecies, e.g., PWD from M. m. musculus and C57BL/6J (henceforth B6) from M. m. domesticus. Hst1 has been identified as a meiotic PR-domain gene (Prdm9) encoding histone 3 methyltransferase in the male offspring of PWD females and B6 males, (PWD×B6)F1. To characterize the incompatibilities underlying hybrid sterility, we phenotyped reproductive and meiotic markers in males with altered copy numbers of Prdm9. A partial rescue of fertility was observed upon removal of the B6 allele of Prdm9 from the azoospermic (PWD×B6)F1 hybrids, whereas removing one of the two Prdm9 copies in PWD or B6 background had no effect on male reproduction. Incompatibility(ies) not involving Prdm9B6 also acts in the (PWD×B6)F1 hybrids, since the correction of hybrid sterility by Prdm9B6 deletion was not complete. Additions and subtractions of Prdm9 copies, as well as allelic replacements, improved meiotic progression and fecundity also in the progeny-producing reciprocal (B6×PWD)F1 males. Moreover, an increased dosage of Prdm9 and reciprocal cross enhanced fertility of other sperm-carrying male hybrids, (PWD×B6-C3H.Prdm9)F1, harboring another Prdm9 allele of M. m. domesticus origin. The levels of Prdm9 mRNA isoforms were similar in the prepubertal testes of all types of F1 hybrids of PWD with B6 and B6-C3H.Prdm9 despite their different prospective fertility, but decreased to 53% after removal of Prdm9B6. Therefore, the Prdm9B6 allele probably takes part in posttranscriptional dominant-negative hybrid interaction(s) absent in the parental strains. Disturbed gametogenesis in the progeny of two fertile parental forms is called hybrid sterility; it is an important part of reproductive barriers between species. The Dobzhansky-Muller model of incompatibilities explains reproductive isolation between species by incorrect interactions between genes. Hybrid sterility 1 (Hst1) is one of the genes causing meiotic arrest in F1 male hybrids between certain Mus musculus musculus (e.g., the PWD strain) and M. m. domesticus (C57BL/6J etc.) mice. Hst1, the first mammalian candidate for a speciation gene, was identified as a meiotic PR/SET-domain gene, Prdm9, but the mechanism causing sterility has remained unknown. While the F1 male offspring of C57BL/6J males and PWD females produce no sperm, the males from the reciprocal cross using PWD males and C57BL/6J females yield progeny. Here we show that the meiotic progress and fertility of hybrid males from both F1 crosses improved by removal as well as overexpression of the C57BL/6J allele of Prdm9, suggesting that Prdm9 interactions not present in the parental species (incompatibilities) play a role in hybrid sterility. Furthermore, the Prdm9 dosage also controlled fecundity in other F1 hybrids, indicating that this gene is an important regulator of mouse hybrid fertility.
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Affiliation(s)
- Petr Flachs
- Department of Mouse Molecular Genetics and Center for Applied Genomics, Institute of Molecular Genetics of the Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Ondřej Mihola
- Department of Mouse Molecular Genetics and Center for Applied Genomics, Institute of Molecular Genetics of the Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Petr Šimeček
- Department of Mouse Molecular Genetics and Center for Applied Genomics, Institute of Molecular Genetics of the Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Soňa Gregorová
- Department of Mouse Molecular Genetics and Center for Applied Genomics, Institute of Molecular Genetics of the Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - John C. Schimenti
- Center for Vertebrate Genomics, Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - Yasuhisa Matsui
- Cell Resource Center for Biomedical Research, Institute of Development, Aging, and Cancer, Tohoku University, Sendai, Japan
| | - Frédéric Baudat
- Institut de Génétique Humaine, CNRS UPR 1142, Montpellier, France
| | - Bernard de Massy
- Institut de Génétique Humaine, CNRS UPR 1142, Montpellier, France
| | - Jaroslav Piálek
- Institute of Vertebrate Biology, Academy of Sciences CR, Brno and Studenec, Czech Republic
| | - Jiří Forejt
- Department of Mouse Molecular Genetics and Center for Applied Genomics, Institute of Molecular Genetics of the Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Zdenek Trachtulec
- Department of Mouse Molecular Genetics and Center for Applied Genomics, Institute of Molecular Genetics of the Academy of Sciences of the Czech Republic, Prague, Czech Republic
- * E-mail:
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Abstract
One of the most straightforward approaches to making novel biological discoveries is the forward genetic screen. The time is ripe for forward genetic screens in the mouse since the mouse genome is sequenced, but the function of many of the genes remains unknown. Today, with careful planning, such screens are within the reach of even small individual labs. In this chapter we first discuss the types of screens in existence, as well as how to design a screen to recover mutations that are relevant to the interests of a lab. We then describe how to create mutations using the chemical N-ethyl-N-nitrosourea (ENU), including a detailed injection protocol. Next, we outline breeding schemes to establish mutant lines for each type of screen. Finally, we explain how to map mutations using recombination and how to ensure that a particular mutation causes a phenotype. Our goal is to make forward genetics in the mouse accessible to any lab with the desire to do it.
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Affiliation(s)
- Vanessa L Horner
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, USA.
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Mu W, Munroe RJ, Barker AK, Schimenti JC. PDCD2 is essential for inner cell mass development and embryonic stem cell maintenance. Dev Biol 2010; 347:279-88. [PMID: 20813103 DOI: 10.1016/j.ydbio.2010.08.026] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Revised: 08/06/2010] [Accepted: 08/24/2010] [Indexed: 01/15/2023]
Abstract
PDCD2 is a conserved eukaryotic protein implicated in cell cycle regulation by virtue of its interactions with HCFC1 and the NCOR1/SIN3A corepressor complex. Pdcd2 transcripts are enriched in ES cells and other somatic stem cells, and its ortholog is essential for hematopoietic stem cell maintenance in Drosophila. To characterize the physiological role(s) of mammalian PDCD2, we created a disruption allele in mice. Pdcd2(-/-) embryos underwent implantation but did not undergo further development. Inner cell masses (ICMs) from Pdcd2(-/-) blastocysts failed to outgrow in vitro. Furthermore, embryonic stem cells (ESCs) require PDCD2 as demonstrated by the inability to generate Pdcd2(-/-) ESCs in the absence of an ectopic transgene. Upon differentiation of ESCs by retinoic acid treatment or LIF deprivation, PDCD2 levels declined. In conjunction with prior studies, these results indicate that in vivo, PDCD2 is critical for blastomere and ESC maintenance by contributing to the regulation of genes in a manner essential to the undifferentiated state of these cells.
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Affiliation(s)
- Weipeng Mu
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, USA
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Conserved alternative and antisense transcripts at the programmed cell death 2 locus. BMC Genomics 2007; 8:20. [PMID: 17233890 PMCID: PMC1800895 DOI: 10.1186/1471-2164-8-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2006] [Accepted: 01/18/2007] [Indexed: 01/12/2023] Open
Abstract
Background The programmed cell death 2 (Pdcd2) gene on mouse chromosome 17 was evaluated as a member of a highly conserved synteny, a candidate for an imprinted locus, and a candidate for the Hybrid sterility 1 (Hst1) gene. Results New mouse transcripts were identified at this locus: an alternative Pdcd2 mRNA skipping the last two coding exons and two classes of antisense RNAs. One class of the antisense RNA overlaps the alternative exon and the other the entire Pdcd2 gene. The antisense RNAs are alternative transcripts of the neighboring TATA-binding protein gene (Tbp) that are located mainly in the cell nucleus. Analogous alternative PDCD2 forms truncating the C-terminal domain were also detected in human and chicken. Alternative transcripts of the chicken PDCD2 and TBP genes also overlap. No correlation in the transcription of the alternative and overlapping mRNAs was detected. Allelic sequencing and transcription studies did not reveal any support for the candidacy of Pdcd2 for Hst1. No correlated expression of Pdcd2 with the other two genes of the highly conserved synteny was observed. Pdcd2, Chd1, and four other genes from this region were not imprinted in the embryo. Conclusion The conservation of alternative transcription of the Pdcd2 gene in mouse, human and chicken suggests the biological importance of such truncated protein. The biological function of the alternative PDCD2 is likely to be opposite to that of the constitutive form. The ratio of the constitutive and alternative Pdcd2 mRNAs differs in the tissues, suggesting a developmental role. The identified Tbp-alternative Pdcd2-antisense transcripts may interfere with the transcription of the Pdcd2 gene, as they are transcribed at a comparable level. The conservation of the Pdcd2/Tbp sense-antisense overlap in the mouse and chicken points out its biological relevance. Our results also suggest that some cDNAs in databases labeled as noncoding are incomplete alternative cDNAs of neighboring protein-coding genes.
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Howell GR, Munroe RJ, Schimenti JC. Transgenic rescue of the mouse t complex haplolethal locus Thl1. Mamm Genome 2005; 16:838-46. [PMID: 16284799 DOI: 10.1007/s00335-005-0045-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2005] [Accepted: 07/07/2005] [Indexed: 10/25/2022]
Abstract
Chromosomal deletions can uncover haploinsufficient or imprinted regions of the genome. Previously, the haploinsufficient locus t haplolethal 1 (Thl1) was identified and localized to a 1.3-Mb region using overlapping deletions around the Sod2 and D17Leh94 loci of the mouse t complex on Chr 17. Germline chimeric mice, produced from embryonic stem (ES) cells containing radiation-induced deletions of the Thl1 locus, never produced viable deletion-bearing progeny when mated to C57BL/6J (B6) females. However, deletion-bearing offspring could be obtained by mating to females of other strains. In this article we describe a transgenic approach to narrow the critical region for Thl1. BAC clones were introduced into a deletion-bearing ES cell line and one was shown to rescue the Thl1 phenotype, reducing the critical region to 140 kb. Analysis of the gene content of this region suggests two strong Thl1 candidates, Pdcd2 and a novel SET domain-containing gene termed Tset1. A more detailed analysis using mice carrying overlapping deletions identified subregions that influence the phenotypic characteristics of Thl1 hemizygotes.
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Affiliation(s)
- Gareth R Howell
- The Jackson Laboratory, 600 Main Street, Bar Harbor, Maine 04660, USA
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Chick WSH, Mentzer SE, Carpenter DA, Rinchik EM, Johnson D, You Y. X-ray-induced deletion complexes in embryonic stem cells on mouse chromosome 15. Mamm Genome 2005; 16:661-71. [PMID: 16245023 DOI: 10.1007/s00335-005-0011-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2005] [Accepted: 05/31/2005] [Indexed: 12/20/2022]
Abstract
Chromosomal deletions have long been used as genetic tools in dissecting the functions of complex genomes, and new methodologies are still being developed to achieve the maximum coverage. In the mouse, where the chromosomal deletion coverage is far less extensive than that in Drosophila, substantial coverage of the genome with deletions is strongly desirable. This article reports the generation of three deletion complexes in the distal part of mouse Chromosome (Chr) 15. Chromosomal deletions were efficiently induced by X rays in embryonic stem (ES) cells around the Otoconin 90 (Oc 90), SRY-box-containing gene 10 (Sox 10), and carnitine palmitoyltransferase 1b (Cpt 1 b) loci. Deletions encompassing the Oc 90 and Sox 10 loci were transmitted to the offspring of the chimeric mice that were generated from deletion-bearing ES cells. Whereas deletion complexes encompassing the Sox 10 and the Cpt 1 b loci overlap each other, no overlap of the Oc 90 complex with the Sox 10 complex was found, possibly indicating the existence of a haploinsufficient gene located between Oc 90 and Sox 10. Deletion frequency and size induced by X rays depend on the selective locus, possibly reflecting the existence of haplolethal genes in the vicinity of these loci that yield fewer and smaller deletions. Deletions induced in ES cells by X rays vary in size and location of breakpoints, which makes them desirable for mapping and for functional genomics studies.
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Affiliation(s)
- Wallace S H Chick
- Graduate School of Genome Sciences and Technology, The University of Tennessee, Knoxville, Tennessee 37996, USA
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Chao HHJ, Mentzer SE, Schimenti JC, You Y. Overlapping deletions define novel embryonic lethal loci in the mouse t complex. Genesis 2003; 35:133-42. [PMID: 12533796 DOI: 10.1002/gene.10174] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
SUMMARY The t complex region of mouse chromosome 17 contains genetic information critical for embryonic development. To identify and map loci required for normal embryogenesis, a set of overlapping deletions (D17Aus9(df10J), D17Aus9(df12J), and D17Aus9(df13J)) surrounding the D17Aus9 locus and one encompassing the T locus, Del(17)T(7J), were bred in various combinations and the consequences of nullizygosity in overlapping regions were examined. The results indicated that there are at least two functional units within 1 cM of D17Aus9. l17J1 is a peri-implantation lethal mutation within the region deleted in D17Aus9(df13J), whereas l17J2 is a later-acting lethal defined by the region of overlap between Del(17)T(7J) and D17Aus9(df12J). Del(17)T(7J)/D17Aus9(df12J) embryos die around 10.5 dpc. The development of the mutant embryos is characterized by lack of axial rotation, an abnormal notochord structure, and a ballooning pericardium. These studies demonstrate the value of overlapping deletion complexes, as opposed to individual deletion complexes, for the identification, mapping, and analysis of genes required for embryonic development.
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Affiliation(s)
- Hanna H J Chao
- Life Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6445, USA
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