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Maternally provided LSD1/KDM1A enables the maternal-to-zygotic transition and prevents defects that manifest postnatally.

Wasson JA, Simon AK, Myrick DA, Wolf G, Driscoll S, Pfaff SL, Macfarlan TS, Katz DJ - Elife (2016)

Bottom Line: Moreover, partial loss of maternal LSD1/KDM1A results in striking phenotypes weeks after fertilization; including perinatal lethality and abnormal behavior in surviving adults.These maternal effect hypomorphic phenotypes are associated with alterations in DNA methylation and expression at imprinted genes.These results establish a novel mammalian paradigm where defects in early epigenetic reprogramming can lead to defects that manifest later in development.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology, Emory University School of Medicine, Atlanta, United States.

ABSTRACT
Somatic cell nuclear transfer has established that the oocyte contains maternal factors with epigenetic reprogramming capacity. Yet the identity and function of these maternal factors during the gamete to embryo transition remains poorly understood. In C. elegans, LSD1/KDM1A enables this transition by removing H3K4me2 and preventing the transgenerational inheritance of transcription patterns. Here we show that loss of maternal LSD1/KDM1A in mice results in embryonic arrest at the 1-2 cell stage, with arrested embryos failing to undergo the maternal-to-zygotic transition. This suggests that LSD1/KDM1A maternal reprogramming is conserved. Moreover, partial loss of maternal LSD1/KDM1A results in striking phenotypes weeks after fertilization; including perinatal lethality and abnormal behavior in surviving adults. These maternal effect hypomorphic phenotypes are associated with alterations in DNA methylation and expression at imprinted genes. These results establish a novel mammalian paradigm where defects in early epigenetic reprogramming can lead to defects that manifest later in development.

No MeSH data available.


Related in: MedlinePlus

Lack of normal Kdm1aGdf9 and Kdm1aZp3 embryos at embryonic day 1.5 and 2.5.(A,B,D,E,F) Brightfield images of embryonic day 1.5 (e1.5) M+Z+ 1-cell (A) and 2-cell (B) embryos and M-Z+ 1-cell (D), 2-cell (E), and fragmented (F) embryos derived from Kdm1aGdf9 control and mutant mothers. (C,G,H) Brightfield images of e2.5 M+Z+ 8-cell (C) embryo and M-Z+ abnormal 1-cell (G), and fragmented (H) embryos derived from Kdm1aGdf9 control and mutant mothers. (I) Percentage of fragmented (purple), unfertilized oocyte or 1C (green), and 2C (yellow) embryos from Kdm1aGdf9 control and mutant mothers. n = 123 for Kdm1aGdf9 M+Z+ control embryos from 8 litters. n = 104 for Kdm1aGdf9 M-Z+ embryos from 8 litters. (J) Brightfield image of 3-cell M-Z+ embryo derived from a Kdm1aZp3 mutant mother. (K) Brightfield image of 4-cell M-Z+ embryo derived from a Kdm1aZp3 mutant mother.DOI:http://dx.doi.org/10.7554/eLife.08848.007
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fig2s1: Lack of normal Kdm1aGdf9 and Kdm1aZp3 embryos at embryonic day 1.5 and 2.5.(A,B,D,E,F) Brightfield images of embryonic day 1.5 (e1.5) M+Z+ 1-cell (A) and 2-cell (B) embryos and M-Z+ 1-cell (D), 2-cell (E), and fragmented (F) embryos derived from Kdm1aGdf9 control and mutant mothers. (C,G,H) Brightfield images of e2.5 M+Z+ 8-cell (C) embryo and M-Z+ abnormal 1-cell (G), and fragmented (H) embryos derived from Kdm1aGdf9 control and mutant mothers. (I) Percentage of fragmented (purple), unfertilized oocyte or 1C (green), and 2C (yellow) embryos from Kdm1aGdf9 control and mutant mothers. n = 123 for Kdm1aGdf9 M+Z+ control embryos from 8 litters. n = 104 for Kdm1aGdf9 M-Z+ embryos from 8 litters. (J) Brightfield image of 3-cell M-Z+ embryo derived from a Kdm1aZp3 mutant mother. (K) Brightfield image of 4-cell M-Z+ embryo derived from a Kdm1aZp3 mutant mother.DOI:http://dx.doi.org/10.7554/eLife.08848.007

Mentions: To determine if there is a functional requirement for maternal KDM1A in mice, we crossed Kdm1aVasa, Kdm1aGdf9 and Kdm1aZp3 females to wild-type males to generate heterozygous offspring (Figure 1—figure supplement 2). In mice, zygotic transcription begins in the 1C embryo just prior to the first cleavage to the 2C stage (Aoki et al., 1997; Hamatani et al., 2004; Xue et al., 2013). The heterozygous offspring from the maternally deleted mothers have a normal Kdm1a gene on the paternal allele. Thus, crossing maternally deleted mothers to wild-type fathers enables us to isolate the maternal function of KDM1A (Maternal-, Zygotic+, hereafter referred to as M-Z+). M-Z+ heterozygous embryos derived from Kdm1aGdf9 mutant mothers are hereafter referred to as Kdm1aGdf9 M-Z+ embryos, while M+Z+ heterozygous embryos derived from littermate control mothers that are Cre minus are hereafter referred to as Kdm1aGdf9 M+Z+ embryos. Kdm1aGdf9 M-Z+ embryos exhibit embryonic arrest at the 1-2C stage (Figure 2—figure supplement 1A–I). Specifically, in control Kdm1aGdf9 M+Z+ embryos at embryonic day 1.5 (e1.5), we observe 7% fragmented/degraded embryos, 65% 1-cell embryos and 28% 2-cell embryos (n=135, Figure 2—figure supplement 1I). In contrast, in Kdm1aGdf9 M-Z+ embryos at e1.5 we observe 40% fragmented/degraded embryos, 59% unfertilized oocytes or 1-cell embryos, and only 1% 2C embryos (n=134, Figure 2—figure supplement 1I). The vast majority of the non-degraded Kdm1aGdf9 M-Z+ embryos are clearly fertilized and arrested at the 1C stage. However, we do occasionally observe unfertilized oocytes. In addition, we sometimes observe embryos that are highly abnormal morphologically and are difficult to clearly assign to a particular category. As a result, we quantified these Kdm1aGdf9 M-Z+ embryos together. Nevertheless, compared to Kdm1aGdf9 M+Z+ embryos, Kdm1aGdf9 M-Z+ embryos have a large increase in the number of fragmented/degraded embryos at the expense of normal 2C embryos (Figure 2—figure supplement 1I). Also, the remaining 1C and 2C Kdm1aGdf9 M-Z+ embryos do not progress beyond the 1-2C stage, as we never observe any later stage embryos even at e2.5 (Figure 2—figure supplement 1C,G,H).


Maternally provided LSD1/KDM1A enables the maternal-to-zygotic transition and prevents defects that manifest postnatally.

Wasson JA, Simon AK, Myrick DA, Wolf G, Driscoll S, Pfaff SL, Macfarlan TS, Katz DJ - Elife (2016)

Lack of normal Kdm1aGdf9 and Kdm1aZp3 embryos at embryonic day 1.5 and 2.5.(A,B,D,E,F) Brightfield images of embryonic day 1.5 (e1.5) M+Z+ 1-cell (A) and 2-cell (B) embryos and M-Z+ 1-cell (D), 2-cell (E), and fragmented (F) embryos derived from Kdm1aGdf9 control and mutant mothers. (C,G,H) Brightfield images of e2.5 M+Z+ 8-cell (C) embryo and M-Z+ abnormal 1-cell (G), and fragmented (H) embryos derived from Kdm1aGdf9 control and mutant mothers. (I) Percentage of fragmented (purple), unfertilized oocyte or 1C (green), and 2C (yellow) embryos from Kdm1aGdf9 control and mutant mothers. n = 123 for Kdm1aGdf9 M+Z+ control embryos from 8 litters. n = 104 for Kdm1aGdf9 M-Z+ embryos from 8 litters. (J) Brightfield image of 3-cell M-Z+ embryo derived from a Kdm1aZp3 mutant mother. (K) Brightfield image of 4-cell M-Z+ embryo derived from a Kdm1aZp3 mutant mother.DOI:http://dx.doi.org/10.7554/eLife.08848.007
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fig2s1: Lack of normal Kdm1aGdf9 and Kdm1aZp3 embryos at embryonic day 1.5 and 2.5.(A,B,D,E,F) Brightfield images of embryonic day 1.5 (e1.5) M+Z+ 1-cell (A) and 2-cell (B) embryos and M-Z+ 1-cell (D), 2-cell (E), and fragmented (F) embryos derived from Kdm1aGdf9 control and mutant mothers. (C,G,H) Brightfield images of e2.5 M+Z+ 8-cell (C) embryo and M-Z+ abnormal 1-cell (G), and fragmented (H) embryos derived from Kdm1aGdf9 control and mutant mothers. (I) Percentage of fragmented (purple), unfertilized oocyte or 1C (green), and 2C (yellow) embryos from Kdm1aGdf9 control and mutant mothers. n = 123 for Kdm1aGdf9 M+Z+ control embryos from 8 litters. n = 104 for Kdm1aGdf9 M-Z+ embryos from 8 litters. (J) Brightfield image of 3-cell M-Z+ embryo derived from a Kdm1aZp3 mutant mother. (K) Brightfield image of 4-cell M-Z+ embryo derived from a Kdm1aZp3 mutant mother.DOI:http://dx.doi.org/10.7554/eLife.08848.007
Mentions: To determine if there is a functional requirement for maternal KDM1A in mice, we crossed Kdm1aVasa, Kdm1aGdf9 and Kdm1aZp3 females to wild-type males to generate heterozygous offspring (Figure 1—figure supplement 2). In mice, zygotic transcription begins in the 1C embryo just prior to the first cleavage to the 2C stage (Aoki et al., 1997; Hamatani et al., 2004; Xue et al., 2013). The heterozygous offspring from the maternally deleted mothers have a normal Kdm1a gene on the paternal allele. Thus, crossing maternally deleted mothers to wild-type fathers enables us to isolate the maternal function of KDM1A (Maternal-, Zygotic+, hereafter referred to as M-Z+). M-Z+ heterozygous embryos derived from Kdm1aGdf9 mutant mothers are hereafter referred to as Kdm1aGdf9 M-Z+ embryos, while M+Z+ heterozygous embryos derived from littermate control mothers that are Cre minus are hereafter referred to as Kdm1aGdf9 M+Z+ embryos. Kdm1aGdf9 M-Z+ embryos exhibit embryonic arrest at the 1-2C stage (Figure 2—figure supplement 1A–I). Specifically, in control Kdm1aGdf9 M+Z+ embryos at embryonic day 1.5 (e1.5), we observe 7% fragmented/degraded embryos, 65% 1-cell embryos and 28% 2-cell embryos (n=135, Figure 2—figure supplement 1I). In contrast, in Kdm1aGdf9 M-Z+ embryos at e1.5 we observe 40% fragmented/degraded embryos, 59% unfertilized oocytes or 1-cell embryos, and only 1% 2C embryos (n=134, Figure 2—figure supplement 1I). The vast majority of the non-degraded Kdm1aGdf9 M-Z+ embryos are clearly fertilized and arrested at the 1C stage. However, we do occasionally observe unfertilized oocytes. In addition, we sometimes observe embryos that are highly abnormal morphologically and are difficult to clearly assign to a particular category. As a result, we quantified these Kdm1aGdf9 M-Z+ embryos together. Nevertheless, compared to Kdm1aGdf9 M+Z+ embryos, Kdm1aGdf9 M-Z+ embryos have a large increase in the number of fragmented/degraded embryos at the expense of normal 2C embryos (Figure 2—figure supplement 1I). Also, the remaining 1C and 2C Kdm1aGdf9 M-Z+ embryos do not progress beyond the 1-2C stage, as we never observe any later stage embryos even at e2.5 (Figure 2—figure supplement 1C,G,H).

Bottom Line: Moreover, partial loss of maternal LSD1/KDM1A results in striking phenotypes weeks after fertilization; including perinatal lethality and abnormal behavior in surviving adults.These maternal effect hypomorphic phenotypes are associated with alterations in DNA methylation and expression at imprinted genes.These results establish a novel mammalian paradigm where defects in early epigenetic reprogramming can lead to defects that manifest later in development.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology, Emory University School of Medicine, Atlanta, United States.

ABSTRACT
Somatic cell nuclear transfer has established that the oocyte contains maternal factors with epigenetic reprogramming capacity. Yet the identity and function of these maternal factors during the gamete to embryo transition remains poorly understood. In C. elegans, LSD1/KDM1A enables this transition by removing H3K4me2 and preventing the transgenerational inheritance of transcription patterns. Here we show that loss of maternal LSD1/KDM1A in mice results in embryonic arrest at the 1-2 cell stage, with arrested embryos failing to undergo the maternal-to-zygotic transition. This suggests that LSD1/KDM1A maternal reprogramming is conserved. Moreover, partial loss of maternal LSD1/KDM1A results in striking phenotypes weeks after fertilization; including perinatal lethality and abnormal behavior in surviving adults. These maternal effect hypomorphic phenotypes are associated with alterations in DNA methylation and expression at imprinted genes. These results establish a novel mammalian paradigm where defects in early epigenetic reprogramming can lead to defects that manifest later in development.

No MeSH data available.


Related in: MedlinePlus