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Tan J, Song GD, Song JS, Ren SH, Li CL, Zheng ZY, Zhao WD. Locating a modifier gene of Ovum mutant through crosses between DDK and C57BL/6J inbred strains in mice. J Genet 2016; 95:297-302. [PMID: 27350672 DOI: 10.1007/s12041-016-0633-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
A striking infertile phenotype has been discovered in the DDK strain of mouse. The DDK females are usually infertile when crossed with males of other inbred strains, whereas DDK males exhibit normal fertility in reciprocal crosses. This phenomenon is caused by mutation in the ovum (Om) locus on chromosome 11 and known as the DDK syndrome. Previously, some research groups reported that the embryonic mortality deviated from the semilethal rate in backcrosses between heterozygous (Om/+) females and males of other strains. This embryonic mortality exhibited an aggravated trend with increasing background genes of other strains. These results indicated that some modifier genes of Om were present in other strains. In the present study, a population of N₂2 (Om/+) females from the backcrosses between C57BL/6J (B6) and F₁ (B6♀ × DDK♂) was used to map potential modifier genes of Om. Quantitative trait locus showed that a major locus, namely Amom1 (aggravate modifier gene of Om 1), was located at the middle part of chromosome 9 in mice. The Amom1 could increase the expressivity of Om gene, thereby aggravating embryonic lethality when heterozygous (Om/+) females mated with males of B6 strain. Further, the 1.5 LOD-drop analysis indicated that the confidence interval was between 37.54 and 44.46 cM, ~6.92 cM. Amom1 is the first modifier gene of Om in the B6 background.
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Affiliation(s)
- Jing Tan
- Engineering College of Animal Husbandry and Veterinary Science, Henan Agricultural University, Zhengzhou 450002, Henan, People's Republic of
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Predazzi IM, Sobota RS, Sanna S, Bush WS, Bartlett J, Lilley JS, Linton MF, Schlessinger D, Cucca F, Fazio S, Williams SM. Sex-Specific Parental Effects on Offspring Lipid Levels. J Am Heart Assoc 2015; 4:JAHA.115.001951. [PMID: 26126546 PMCID: PMC4608079 DOI: 10.1161/jaha.115.001951] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Background Plasma lipid levels are highly heritable traits, but known genetic loci can only explain a small portion of their heritability. Methods and Results In this study, we analyzed the role of parental levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides (TGs) in explaining the values of the corresponding traits in adult offspring. We also evaluated the contribution of nongenetic factors that influence lipid traits (age, body mass index, smoking, medications, and menopause) alone and in combination with variability at the genetic loci known to associate with TC, LDL-C, HDL-C, and TG levels. We performed comparisons among different sex-specific regression models in 416 families from the Framingham Heart Study and 304 from the SardiNIA cohort. Models including parental lipid levels explain significantly more of the trait variation than models without these measures, explaining up to ≈39% of the total trait variation. Of this variation, the parent-of-origin effect explains as much as ≈15% and it does so in a sex-specific way. This observation is not owing to shared environment, given that spouse-pair correlations were negligible (<1.5% explained variation in all cases) and is distinct from previous genetic and acquired factors that are known to influence serum lipid levels. Conclusions These findings support the concept that unknown genetic and epigenetic contributors are responsible for most of the heritable component of the plasma lipid phenotype, and that, at present, the clinical utility of knowing age-matched parental lipid levels in assessing risk of dyslipidemia supersedes individual locus effects. Our results support the clinical utility of knowing parental lipid levels in assessing future risk of dyslipidemia.
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Affiliation(s)
- Irene M Predazzi
- Atherosclerosis Research Unit, Departments of Medicine and Pharmacology, Vanderbilt University Medical Center, Nashville, TN (I.M.P., J.S.L., M.R.F.L., S.F.) Knight Cardiovascular Institute, Center for Preventive Cardiology, Oregon Health and Science University, Portland, OR (I.M.P., S.F.)
| | - Rafal S Sobota
- Center for Human Genetics Research, Vanderbilt University Medical Center, Nashville, TN (R.S.S., W.S.B.) Department of Genetics, Geisel School of Medicine, Dartmouth College, Hanover, NH (R.S.S., J.B., S.M.W.)
| | - Serena Sanna
- Istituto di Ricerca Genetica e Biomedica (IRGB), CNR, Monserrato, Italy (S.S., F.C.)
| | - William S Bush
- Center for Human Genetics Research, Vanderbilt University Medical Center, Nashville, TN (R.S.S., W.S.B.) Department of Epidemiology and Biostatistics, Case Western Reserve University, Cleveland, OH (W.S.B.)
| | - Jacquelaine Bartlett
- Department of Genetics, Geisel School of Medicine, Dartmouth College, Hanover, NH (R.S.S., J.B., S.M.W.)
| | - Jessica S Lilley
- Atherosclerosis Research Unit, Departments of Medicine and Pharmacology, Vanderbilt University Medical Center, Nashville, TN (I.M.P., J.S.L., M.R.F.L., S.F.) Division of Endocrinology, Department of Pediatrics, University of Mississippi School of Medicine, Jackson, MS (J.S.L.)
| | - MacRae F Linton
- Atherosclerosis Research Unit, Departments of Medicine and Pharmacology, Vanderbilt University Medical Center, Nashville, TN (I.M.P., J.S.L., M.R.F.L., S.F.)
| | | | - Francesco Cucca
- Istituto di Ricerca Genetica e Biomedica (IRGB), CNR, Monserrato, Italy (S.S., F.C.)
| | - Sergio Fazio
- Atherosclerosis Research Unit, Departments of Medicine and Pharmacology, Vanderbilt University Medical Center, Nashville, TN (I.M.P., J.S.L., M.R.F.L., S.F.) Knight Cardiovascular Institute, Center for Preventive Cardiology, Oregon Health and Science University, Portland, OR (I.M.P., S.F.)
| | - Scott M Williams
- Department of Genetics, Geisel School of Medicine, Dartmouth College, Hanover, NH (R.S.S., J.B., S.M.W.)
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Shih EK, Sekerková G, Ohtsuki G, Aldinger KA, Chizhikov VV, Hansel C, Mugnaini E, Millen KJ. The Spontaneous Ataxic Mouse Mutant Tippy is Characterized by a Novel Purkinje Cell Morphogenesis and Degeneration Phenotype. CEREBELLUM (LONDON, ENGLAND) 2015; 14:292-307. [PMID: 25626522 PMCID: PMC4832921 DOI: 10.1007/s12311-014-0640-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
This study represents the first detailed analysis of the spontaneous neurological mouse mutant, tippy, uncovering its unique cerebellar phenotype. Homozygous tippy mutant mice are small, ataxic, and die around weaning. Although the cerebellum shows grossly normal foliation, tippy mutants display a complex cerebellar Purkinje cell phenotype consisting of abnormal dendritic branching with immature spine features and patchy, non-apoptotic cell death that is associated with widespread dystrophy and degeneration of the Purkinje cell axons throughout the white matter, the cerebellar nuclei, and the vestibular nuclei. Moderate anatomical abnormalities of climbing fiber innervation of tippy mutant Purkinje cells were not associated with changes in climbing fiber-EPSC amplitudes. However, decreased ESPC amplitudes were observed in response to parallel fiber stimulation and correlated well with anatomical evidence for patchy dark cell degeneration of Purkinje cell dendrites in the molecular layer. The data suggest that the Purkinje neurons are a primary target of the tippy mutation. Furthermore, we hypothesize that the Purkinje cell axonal pathology together with disruptions in the balance of climbing fiber and parallel fiber-Purkinje cell input in the cerebellar cortex underlie the ataxic phenotype in these mice. The constellation of Purkinje cell dendritic malformation and degeneration phenotypes in tippy mutants is unique and has not been reported in any other neurologic mutant. Fine mapping of the tippy mutation to a 2.1 MB region of distal chromosome 9, which does not encompass any gene previously implicated in cerebellar development or neuronal degeneration, confirms that the tippy mutation identifies novel biology and gene function.
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Affiliation(s)
- Evelyn K. Shih
- Division of Neurology, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania 10194
| | - Gabriella Sekerková
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611
| | - Gen Ohtsuki
- Department of Molecular Physiology, Kyushu University, Kyushu University, Graduate School of Medical Sciences, Higashi-ku, Fukuoka 812-8582, Japan
| | - Kimberly A. Aldinger
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, Washington, 98101
| | - Victor V. Chizhikov
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, Tennessee, 38163
| | - Christian Hansel
- Department of Neurobiology, The University of Chicago, Chicago, Illinois 60637
| | - Enrico Mugnaini
- Department of Cellular and Molecular Biology, Feinberg School of Medicine and Hugh Knowles Center, Northwestern University, Chicago, Illinois, 60611
| | - Kathleen J. Millen
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, Washington, 98101
- The University of Washington Department of Pediatrics, Seattle, Washington, 98101
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Abstract
DDK syndrome is known as embryonic death at the morula-blastocyst stage in female mice of the DDK strain mated with males from other strains (alien males). The embryonic death is interpreted to be caused by incompatibility between oocyte factors and the product from male pronucleus, both of which are under the control of alleles at the same locus on Chromosome 11. This review explains the hypothesis proposing that the embryonic death may be caused primarily by failure in de novo regeneration of centrosomes containing centrioles in the trophectodermal cells. Centrioles disintegrate during gametogenesis in mice, and new centrioles are formed after the cleavage stage during which cell division proceeds with the microtubule organizing center having no centrioles. The failure in de novo regeneration of the centrosomes may arrest cell division and consequently result in embryonic death. Another aspect of DDK syndrome is distortion of the second polar body extrusion in the semi-incompatible cross. In the heterozygous (DDK/alien) oocytes fertilized with alien spermatozoa, DDK allele is more frequently retained in the oocyte nucleus, and alien allele tends to be carried into the polar body. This distortion may possibly be caused by derangement in the spindle system. Therefore, both aspects of DDK syndrome can be regarded as being derived from the abnormality in the centrosome-spindle system according to this hypothesis.
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Affiliation(s)
- Noboru Wakasugi
- Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa-ku, Nagoya 464-8601, Japan.
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