1
|
Latham KE. Preimplantation embryo gene expression: 56 years of discovery, and counting. Mol Reprod Dev 2023; 90:169-200. [PMID: 36812478 DOI: 10.1002/mrd.23676] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 01/23/2023] [Accepted: 02/08/2023] [Indexed: 02/24/2023]
Abstract
The biology of preimplantation embryo gene expression began 56 years ago with studies of the effects of protein synthesis inhibition and discovery of changes in embryo metabolism and related enzyme activities. The field accelerated rapidly with the emergence of embryo culture systems and progressively evolving methodologies that have allowed early questions to be re-addressed in new ways and in greater detail, leading to deeper understanding and progressively more targeted studies to discover ever more fine details. The advent of technologies for assisted reproduction, preimplantation genetic testing, stem cell manipulations, artificial gametes, and genetic manipulation, particularly in experimental animal models and livestock species, has further elevated the desire to understand preimplantation development in greater detail. The questions that drove enquiry from the earliest years of the field remain drivers of enquiry today. Our understanding of the crucial roles of oocyte-expressed RNA and proteins in early embryos, temporal patterns of embryonic gene expression, and mechanisms controlling embryonic gene expression has increased exponentially over the past five and a half decades as new analytical methods emerged. This review combines early and recent discoveries on gene regulation and expression in mature oocytes and preimplantation stage embryos to provide a comprehensive understanding of preimplantation embryo biology and to anticipate exciting future advances that will build upon and extend what has been discovered so far.
Collapse
Affiliation(s)
- Keith E Latham
- Department of Animal Science, Michigan State University, East Lansing, Michigan, USA.,Department of Obstetrics, Gynecology, and Reproductive Biology, Michigan State University, East Lansing, Michigan, USA.,Reproductive and Developmental Sciences Program, Michigan State University, East Lansing, Michigan, USA
| |
Collapse
|
2
|
Sel S, Patzel E, Poggi L, Kaiser D, Kalinski T, Schicht M, Paulsen F, Nass N. Temporal and spatial expression pattern of Nnat during mouse eye development. Gene Expr Patterns 2016; 23-24:7-12. [PMID: 28038958 DOI: 10.1016/j.gep.2016.12.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 12/23/2016] [Accepted: 12/23/2016] [Indexed: 10/20/2022]
Abstract
BACKGROUND Neuronatin (Nnat) was initially identified as a highly expressed gene in neonatal mammalian brain. In this study, we analyze the spatial and temporal expression pattern of Nnat during mouse eye development as well as in the adult. METHODS The expression of Nnat was analyzed on mRNA as well as protein level. The presence of Nnat transcripts in the adult retina was examined using reverse transcription-polymerase chain reaction (RT-PCR). Nnat protein expression was evaluated by Western blot and immunohistochemistry during eye development at embryonic day (E) 12, 15, 16 and postnatal day (P) 7, 14, 30 and 175 (adult). RESULTS Immunohistochemical studies of the developing mouse eye revealed Nnat expression in embryonic and adult neuroretina as well as in corneal epithelial, stromal, endothelial cells and in lens epithelium. Expression of Nnat was detected from E12 onwards and was also present in adult eyes. CONCLUSIONS The expression pattern suggests that Nnat may play an important role during eye development and in the maintenance of mature eye.
Collapse
Affiliation(s)
- Saadettin Sel
- Department of Ophthalmology, University Heidelberg, Germany.
| | - Eva Patzel
- Department of Ophthalmology, University Heidelberg, Germany
| | - Lucia Poggi
- Department of Ophthalmology, University Heidelberg, Germany
| | - Delia Kaiser
- Department of Ophthalmology, University Heidelberg, Germany
| | | | | | | | - Norbert Nass
- Institute of Pathology, University Magdeburg, Germany
| |
Collapse
|
3
|
Abstract
AbstractSeveral common adult diseases appear to be related to impaired fetal growth and this may be caused either by nutritional inadequacies at particular stages of pregnancy or by variation in alleles at specific growth loci. Little is known about the genes involved in the underlying mechanism. This review proposes that at least some of the effects have their origins at imprinted loci, genes that are unusual because they are expressed from only one parental allele. Many imprinted genes are crucial for fetal growth and determine birthweight. They can be disrupted in the early embryo by environmental influences and these disruptions can be inherited through many cell cycles into adult tissues. Their disruption can affect specific organs during fetal development and disruption could affect adult disease in a variety of direct and indirect means. Imprinted genes may be particularly vulnerable to disruption as they are functionally haploid and their expression is regulated by different means from the rest of the genome. Thus many imprinted genes provide plausible candidates for programming adult disease and warrant further study in this context.
Collapse
|
4
|
Liang CG, Han Z, Cheng Y, Zhong Z, Latham KE. Effects of ooplasm transfer on paternal genome function in mice. Hum Reprod 2009; 24:2718-28. [PMID: 19661122 DOI: 10.1093/humrep/dep286] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND The ooplasm plays a central role in forming the paternal pronucleus, and subsequently in regulating the expression of paternally inherited chromosomes. Previous studies in mice have revealed genetic differences in paternal genome processing by ooplasm of different genotypes. Ooplasm donation coupled to intracytoplasmic sperm injection (ICSI) has been used in human assisted reproductive technology (ART). This procedure exposes the developing paternal pronucleus to 'foreign' ooplasm, which may direct aberrant epigenetic processing. The potential effects of the foreign ooplasm on epigenetic information in the paternal pronucleus are unknown; however, some human progeny from ooplasm donation procedures display abnormalities. METHODS In this study, we employed inter-genotype ooplasm transfer followed by ICSI using two mouse strains, C57BL/6 and DBA/2, to explore the influence of foreign ooplasm on paternal pronucleus function. In order to assay for effects on the paternal genome without masking effects of the maternal genome, we examined ooplasm effects in diploid androgenones, which are produced by pronuclear transfer to contain exclusively two paternal sets of chromosomes, in combination with ICSI. RESULTS There was no significant effect of intra-strain ooplasm transfer among androgenones made with either C57BL/6 or DBA/2 oocytes. There was a significant negative effect on androgenone blastocyst development with inter-genotype transfer (10% volume) of DBA/2 ooplasm to C57BL/6 oocytes (P < 0.05). The reciprocal inter-genotype ooplasm transfer had no significant effect. CONCLUSIONS Thus, inter-genotype ooplasm transfer in conjunction with ICSI can alter the function of the paternal genome. However, the effect of foreign ooplasm is restricted to a negative effect, with no evidence of a positive effect. This study provides important new information about the possible consequences of ooplasm donation in human ART.
Collapse
Affiliation(s)
- Cheng-Guang Liang
- The Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | | | | | | | | |
Collapse
|
5
|
Yoshiki A, Ike F, Mekada K, Kitaura Y, Nakata H, Hiraiwa N, Mochida K, Ijuin M, Kadota M, Murakami A, Ogura A, Abe K, Moriwaki K, Obata Y. The mouse resources at the RIKEN BioResource center. Exp Anim 2009; 58:85-96. [PMID: 19448331 DOI: 10.1538/expanim.58.85] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Mice are one of the most important model organisms for studying biological phenomena and diseases processes in life sciences. The biomedical research community has succeeded in launching large scale strategic knockout mouse projects around the world. RIKEN BRC, a comprehensive government funded biological resource center was established in 2001. RIKEN BRC has been acting as the core facility for the mouse resources of the National BioResource Project (NBRP) of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan since 2002. RIKEN BRC is a founding member of the Federation of International Mouse Resources (FIMRe) together with the Jackson Laboratory, the European Mouse Mutant Archive, and other centers, and has participated in the International Mouse Strain Resource (IMSR) to distribute mouse strains worldwide. With the support of the scientific community, RIKEN BRC has collected over 3,800 strains including inbred, transgenic, knockout, wild-derived, and ENU-induced mutant strains. Excellent mouse models for human diseases and gene functions from academic organizations and private companies are distributed through RIKEN BRC. To meet research and social needs, our mice will be rederived to a specific pathogen-free state, strictly monitored for their health, and accurately tested for their genetic modifications and backgrounds. Users can easily access our mouse resources through the internet and obtain the mouse strains for a minimal fee. Cryopreservation of embryos and sperm is used for efficient preservation of the increasing number of mouse resources. RIKEN BRC collaborates with FIMRe members to support Japanese scientists in the use of valuable mouse resources from around the world.
Collapse
|
6
|
Manning M, Lissens W, Liebaers I, Van Steirteghem A, Weidner W. Imprinting analysis in spermatozoa prepared for intracytoplasmic sperm injection (ICSI). INTERNATIONAL JOURNAL OF ANDROLOGY 2001; 24:87-94. [PMID: 11298842 DOI: 10.1046/j.1365-2605.2001.00274.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Genetic imprinting is a mechanism of gene regulation by which only one of the parental copies of a gene is expressed. This process is mediated by the methylation of DNA. As spermatozoa represent exclusively the paternal contribution to a future individual, they are expected to carry the paternal imprint only. For intracytoplasmic sperm injection (ICSI), spermatozoa mostly have to be selected from samples with pathological semen parameters. Correct establishment of the paternal imprint in these spermatozoa has not yet been demonstrated. In the present study, imprinting analysis was undertaken using DNA extracted from spermatozoa from men with normal semen analysis (group A: n=30 patients) and from men with an abnormal sperm count (B: n=30 patients with 5--20 million spermatozoa/mL and C: n=30 patients with < or =5 million spermatozoa/mL) from the ICSI program. It was performed using firstly a conventional methylation-specific polymerase-chain-reaction (M-PCR) and secondly a more sensitive modified hemi-nested M-PCR technique. In addition, a single cell PCR was performed on a total of 88 single spermatozoa (collected from nine males) and on 25 leucocytes (control group). With the conventional M-PCR, exclusively paternal imprints were found in all groups. Using the more sensitive hemi-nested M-PCR, additional maternal imprints were found in 63% of the samples in A, 57% in B and 60% in C. In the single cell PCR, exclusively paternal imprints were detected. Because of the very small amount of DNA (3 pg), a complete amplification failure occurred in 43% of spermatozoa. The correct paternal and maternal imprints were found in 56% of the analysed leucocytes (complete amplification failure in the other 44%). In conclusion, ejaculated spermatozoa from males with medium or high-grade semen pathology proved to have the same imprinting status as those from males with normal semen parameters. As the additional maternal imprints were never found at the single cell level, they were classified as contamination by diploid cells such as leucocytes or immature germ cells in the processed and purified semen samples, which can be detected by a more sensitive PCR method in contrast to the conventional standard PCR.
Collapse
Affiliation(s)
- M Manning
- Department of Urology, University Hospital Giessen, Giessen, Germany.
| | | | | | | | | |
Collapse
|
7
|
Cardoso MC, Leonhardt H. DNA methyltransferase is actively retained in the cytoplasm during early development. J Cell Biol 1999; 147:25-32. [PMID: 10508852 PMCID: PMC2164986 DOI: 10.1083/jcb.147.1.25] [Citation(s) in RCA: 115] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/1999] [Accepted: 09/01/1999] [Indexed: 11/22/2022] Open
Abstract
The overall DNA methylation level sharply decreases from the zygote to the blastocyst stage despite the presence of high levels of DNA methyltransferase (Dnmt1). Surprisingly, the enzyme is localized in the cytoplasm of early embryos despite the presence of several functional nuclear localization signals. We mapped a region in the NH(2)-terminal, regulatory domain of Dnmt1 that is necessary and sufficient for cytoplasmic retention during early development. Altogether, our results suggest that Dnmt1 is actively retained in the cytoplasm, which prevents binding to its DNA substrate in the nucleus and thereby contributes to the erasure of gamete-specific epigenetic information during early mammalian development.
Collapse
Affiliation(s)
- M. Cristina Cardoso
- Max Delbrück Center for Molecular Medicine, Franz Volhard Clinic, 13125 Berlin, Germany
| | - Heinrich Leonhardt
- Max Delbrück Center for Molecular Medicine, Franz Volhard Clinic, 13125 Berlin, Germany
| |
Collapse
|
8
|
Affiliation(s)
- G Herrick
- Department of Oncological Sciences, University of Utah, Salt Lake City 84132, USA
| | | |
Collapse
|
9
|
Affiliation(s)
- Z Farfel
- Department of Medicine E, Sheba Medical Center, Tel Aviv University, Tel Hashomer, Israel
| | | | | |
Collapse
|
10
|
Abstract
Genomic imprinting in mammals results in the differential expression of maternal and paternal alleles of certain genes. Recent observations have revealed that the regulation of imprinted genes is only partially determined by epigenetic modifications imposed on the two parental genomes during gametogenesis. Additional modifications mediated by factors in the ooplasm, early embryo, or developing embryonic tissues appear to be involved in establishing monoallelic expression for a majority of imprinted genes. As a result, genomic imprinting effects may be manifested in a stage-specific or cell type-specific manner. The developmental aspects of imprinting are reviewed here, and the available molecular data that address the mechanism of allele silencing for three specific imprinted gene domains are considered within the context of explaining how the imprinted gene silencing may be controlled developmentally.
Collapse
Affiliation(s)
- K E Latham
- Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA
| |
Collapse
|
11
|
van Roozendaal CE, Gillis AJ, Klijn JG, van Ooijen B, Claassen CJ, Eggermont AM, Henzen-Logmans SC, Oosterhuis JW, Foekens JA, Looijenga LH. Loss of imprinting of IGF2 and not H19 in breast cancer, adjacent normal tissue and derived fibroblast cultures. FEBS Lett 1998; 437:107-11. [PMID: 9804181 DOI: 10.1016/s0014-5793(98)01211-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Insulin-like growth factors are involved in the paracrine growth regulation of human breast tumor cells. IGF2 is imprinted in most tissues, and shows expression of the paternal allele only. To investigate whether disruption of this monoallelic IGF2 expression is involved in breast cancer development, a series of primary tumors and adjacent, histologically normal, breast tissue samples, as well as matched primary in vitro fibroblast cultures were studied. Biallelic expression (partial) of IGF2 was found in the majority of in vivo samples, and corresponding fibroblast cultures, while monoallelic expression was found in a normal breast sample. In contrast, H19, a closely apposed, but reciprocally imprinted gene, assumed to be regulated by a common control element, showed retention of monoallelic H19 expression in all in vivo and in the majority of in vitro samples. These data indicate that IGF2, but not H19, is prone to loss of imprinting in breast cancer.
Collapse
Affiliation(s)
- C E van Roozendaal
- Department of Medical Oncology, Daniel den Hoed Cancer Center/Academic Hospital, Rotterdam, The Netherlands
| | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Bowen JR, Gibson FL, Leslie GI, Saunders DM. Medical and developmental outcome at 1 year for children conceived by intracytoplasmic sperm injection. Lancet 1998; 351:1529-34. [PMID: 10326534 DOI: 10.1016/s0140-6736(98)10168-x] [Citation(s) in RCA: 177] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
BACKGROUND Intracytoplasmic sperm injection (ICSI) was introduced as a new form of in-vitro fertilisation (IVF) in 1993 and is now accepted as the treatment of choice for severe male infertility in many centres around the world. However, there is little information about the long-term outcome of children conceived by ICSI. We aimed to find out the medical and developmental outcome of children conceived by ICSI at age 1 year. METHODS In this prospective study, we compared the medical and developmental outcome at 1 year of 89 children conceived by ICSI with 84 children conceived by routine IVF, and with 80 children conceived naturally. Formal developmental assessment was done with Bayley Scales of Infant Development (2nd edition) from which a mental development index (MDI) was derived. FINDINGS There was no significant difference in the incidence of major congenital malformations or major health problems in the first year of life. However, the mean Bayley MDI was significantly lower for the children conceived by ICSI than for the children conceived by routine IVF or naturally (95.9 [SD 10.7], 101.8 [8.5], and 102.5 [7.6], respectively, p < 0.0001). 15 (17%) of 89 children conceived by ICSI experienced mildly or significantly delayed development (MDI < 85) at 1 year compared with two (2%) of the 84 children conceived by IVF and one (1%) of the 80 children conceived by natural conception (p < 0.0001). INTERPRETATION Although most children conceived by ICSI are healthy and develop normally, there is an increased risk of mild delays in development at 1 year when compared with children conceived by routine IVF or conceived naturally. These findings support the need for ongoing developmental follow-up of children conceived by ICSI to see whether they are at increased risk of intellectual impairment or learning difficulties at school age.
Collapse
Affiliation(s)
- J R Bowen
- Department of Neonatology, Royal North Shore Hospital, Sydney, Australia
| | | | | | | |
Collapse
|
13
|
Ogura A, Suzuki O, Tanemura K, Mochida K, Kobayashi Y, Matsuda J. Development of normal mice from metaphase I oocytes fertilized with primary spermatocytes. Proc Natl Acad Sci U S A 1998; 95:5611-5. [PMID: 9576931 PMCID: PMC20426 DOI: 10.1073/pnas.95.10.5611] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Primary spermatocytes are the male germ cells before meiosis I. To examine whether these 4n diploid cells are genetically competent to fertilize oocytes and support full embryo development, we introduced the nuclei of pachytene/diplotene spermatocytes into oocytes that were arrested in prophase I (germinal vesicle stage), metaphase I, or metaphase II (Met II). Both the paternal and maternal chromosomes then were allowed to undergo meiosis synchronously until Met II. In the first and second groups, the paternal and maternal chromosomes had intermingled to form a large Met II plate, which was then transferred into a fresh enucleated Met II oocyte. In the third group, the paternal Met II chromosomes were obtained by transferring spermatocyte nuclei into Met II oocytes twice. After activation of the Met II oocytes that were produced, those microfertilized at metaphase I showed the best developmental ability in vitro, and three of these embryos developed into full-term offspring after embryo transfer. Two pups (one male and one female) were proven to be fertile. This finding provides direct evidence that the nuclei of male germ cells acquire the ability to fertilize oocytes before the first meiotic division.
Collapse
Affiliation(s)
- A Ogura
- Department of Veterinary Science, National Institute of Infectious Diseases, 1-23-1, Toyama, Shinjuku, Tokyo 162, Japan.
| | | | | | | | | | | |
Collapse
|
14
|
Latham KE, Sapienza C. Localization of genes encoding egg modifiers of paternal genome function to mouse chromosomes one and two. Development 1998; 125:929-35. [PMID: 9449675 DOI: 10.1242/dev.125.5.929] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
It is now well established that genomic imprinting effects in mammals require a combination of epigenetic modifications imposed during gametogenesis and additional modifications imposed after fertilization. The earliest post-fertilization modifications to be imposed on the genome are those thought to be mediated by factors in the egg cytoplasm. Strain-dependent differences in the actions of these egg modifiers in mice reveal an important potential for genetic variability in the imprinting process, and also provide valuable genetic systems with which to identify some of the factors that participate in imprinting. Previous studies documented a strain-dependent difference in the modification of paternal genome function between the C57BL/6 and DBA/2 mouse strains. This difference is revealed as a difference in developmental potential of androgenetic embryos produced with eggs from females of the two strains by nuclear transplantation. The specificity of the effect for the paternal genome is consistent with an effect on imprinted genes. The egg phenotype is largely independent of the genotype of the fertilizing sperm, and the C57BL/6 phenotype is dominant in reciprocal F1 hybrids. Genetic studies demonstrated that the difference in egg phenotypes between the two strains is most likely controlled by two independently segregating loci. We now report the results of experiments in which the egg phenotypes of the available BxD recombinant inbred mouse strains have been determined. The results of the analysis are consistent with the two locus model, and we have identified candidate chromosomal locations for the two loci. These data demonstrate clearly that differences in how the egg cytoplasm modifies the incoming paternal genome are indeed genetically determined, and vary accordingly.
Collapse
Affiliation(s)
- K E Latham
- Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, PA 19140, USA.
| | | |
Collapse
|
15
|
Fisher EM. The contribution of the mouse to advances in human genetics. ADVANCES IN GENETICS 1997; 35:155-205. [PMID: 9348648 DOI: 10.1016/s0065-2660(08)60450-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- E M Fisher
- Neurogenetics Unit, Imperial College School of Medicine at St. Mary's, London, United Kingdom
| |
Collapse
|
16
|
Kikyo N, Williamson CM, John RM, Barton SC, Beechey CV, Ball ST, Cattanach BM, Surani MA, Peters J. Genetic and functional analysis of neuronatin in mice with maternal or paternal duplication of distal Chr 2. Dev Biol 1997; 190:66-77. [PMID: 9331332 DOI: 10.1006/dbio.1997.8681] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Functional differences between parental genomes are due to differential expression of parental alleles of imprinted genes. Neuronatin (Nnat) is a recently identified paternally expressed imprinted gene that is initially expressed in the rhombomeres and pituitary gland and later more widely in the central and peripheral nervous system mainly in postmitotic and differentiating neuroepithelial cells. Nnat maps to distal chromosome (Chr) 2, which contains an imprinting region that causes morphological abnormalities and early neonatal lethality. More detailed mapping analysis of Nnat showed that it is located between the T26H and T2Wa translocation breakpoints which is, surprisingly, proximal to the reported imprinting region between the T2Wa and T28H translocation breakpoints, suggesting that there may be two distinct imprinting regions on distal chromosome 2. To investigate the potential role of Nnat, we compared normal embryos with those which were PatDp.dist2.T26H (paternal duplication/maternal deficiency of chromosome 2 distal to the translocation breakpoint T26H) and MatDp.dist2.T26H. Expression of Nnat was detected in the PatDp.dist2.T26H embryos, where both copies of Nnat are paternally inherited, and normal embryos but no expression was detected in the MatDp.dist2.T26H embryos with the two maternally inherited copies. The differential expression of Nnat was supported by DNA methylation analysis with the paternally inherited alleles being unmethylated and the maternal alleles fully methylated. Although experimental embryos appeared grossly similar phenotypically in the structures where expression of Nnat was detected, differences in folding of the cerebellum were observed in neonates, and other more subtle developmental or behavioral effects due to gain or loss of Nnat cannot be ruled out.
Collapse
Affiliation(s)
- N Kikyo
- University of Cambridge, United Kingdom
| | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Moss ML. The functional matrix hypothesis revisited. 4. The epigenetic antithesis and the resolving synthesis. Am J Orthod Dentofacial Orthop 1997; 112:410-7. [PMID: 9345153 DOI: 10.1016/s0889-5406(97)70049-0] [Citation(s) in RCA: 133] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In two interrelated articles, the current revision of the functional matrix hypothesis extends to a reconsideration of the relative roles of genomic and of epigenetic processes and mechanisms in the regulation (control, causation) of craniofacial growth and development. The dialectical method was chosen to analyze this matter, because it explicitly provides for the fuller presentation of a genomic thesis, an epigenetic antithesis, and a resolving synthesis. The later two are presented here, where the synthesis suggests that both genomic and epigenetic factors are necessary causes, that neither alone is also a sufficient cause, and that only the two, interacting together, furnish both the necessary and sufficient cause(s) of ontogenesis. This article also provides a comprehensive bibliography that introduces the several new, and still evolving, disciplines that may provide alternative viewpoints capable of resolving this continuing controversy; repetition of the present theoretical bases for the arguments on both sides of these questions seems nonproductive. In their place, it is suggested that the group of disciplines, broadly termed Complexity, would most likely amply repay deeper consideration and application in the study of ontogenesis.
Collapse
Affiliation(s)
- M L Moss
- Department of Anatomy and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.
| |
Collapse
|
18
|
Kopper L, Peták I, Sebestyén A. Molecular genetic basis of cancer development. Ann N Y Acad Sci 1997; 824:1-7. [PMID: 9382434 DOI: 10.1111/j.1749-6632.1997.tb46205.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- L Kopper
- First Institute of Pathology and Experimental Cancer Research, Semmelweis University of Medicine, Budapest, Hungary.
| | | | | |
Collapse
|
19
|
Mostoslavsky R, Bergman Y. DNA methylation: regulation of gene expression and role in the immune system. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1333:F29-50. [PMID: 9294017 DOI: 10.1016/s0304-419x(97)00010-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- R Mostoslavsky
- The Hubert H. Humphrey Center for Experimental Medicine and Cancer Research, The Hebrew University Hadassah Medical School, Jerusalem, Israel
| | | |
Collapse
|
20
|
Affiliation(s)
- L H Looijenga
- Dr. Daniel den Hoed Cancer Center, University Hospital Rotterdam, the Netherlands
| | | | | | | | | |
Collapse
|
21
|
Abstract
Recent studies have revealed that maternal and paternal alleles of some imprinted genes are differentially expressed from the earliest time of expression, with virtually no expression from one of the two alleles, while for other imprinted genes the normally silent allele can be transcribed during early development. In addition, a number of imprinted genes manifest their imprints only in select tissues. These observations indicate that the marks that denote parental chromosome origin need not directly determine allele expression, but rather bias later epigenetic modifications toward a particular allele. Thus, factors expressed at specific stages or in specific cell types are required to silence one parental allele or another. Stage-dependent and tissue-specific epigenetic modifications include the progressive establishment of the mature adult parental allele-specific DNA methylation patterns. These changes resemble and may share a common mechanistic basis with other epigenetic modifications that occur during development. Understanding the mechanisms by which these post-fertilization epigenetic modifications are mediated and regulated will be essential for understanding how genomic imprinting leads to differences in parental allele expression.
Collapse
Affiliation(s)
- K E Latham
- Department of Biochemistry, Temple University School of Medicine, Philadelphia, PA 19140, USA
| |
Collapse
|