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NDR Kinases Are Essential for Somitogenesis and Cardiac Looping during Mouse Embryonic Development.

Schmitz-Rohmer D, Probst S, Yang ZZ, Laurent F, Stadler MB, Zuniga A, Zeller R, Hynx D, Hemmings BA, Hergovich A - PLoS ONE (2015)

Bottom Line: In addition, Ndr1/2-double embryos developed a heart defect that manifests itself as pericardial edemas, obstructed heart tubes and arrest of cardiac looping.The resulting cardiac insufficiency is the likely cause of the lethality of Ndr1/2-double embryos around E10.Ndr1/2-double embryos show defects in somitogenesis and cardiac looping, which reveals their essential functions and shows that the NDR kinases are critically required during the early phase of organogenesis.

View Article: PubMed Central - PubMed

Affiliation: Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.

ABSTRACT
Studies of mammalian tissue culture cells indicate that the conserved and distinct NDR isoforms, NDR1 and NDR2, play essential cell biological roles. However, mice lacking either Ndr1 or Ndr2 alone develop normally. Here, we studied the physiological consequences of inactivating both NDR1 and NDR2 in mice, showing that the lack of both Ndr1/Ndr2 (called Ndr1/2-double mutants) causes embryonic lethality. In support of compensatory roles for NDR1 and NDR2, total protein and activating phosphorylation levels of the remaining NDR isoform were elevated in mice lacking either Ndr1 or Ndr2. Mice retaining one single wild-type Ndr allele were viable and fertile. Ndr1/2-double embryos displayed multiple phenotypes causing a developmental delay from embryonic day E8.5 onwards. While NDR kinases are not required for notochord formation, the somites of Ndr1/2-double embryos were smaller, irregularly shaped and unevenly spaced along the anterior-posterior axis. Genes implicated in somitogenesis were down-regulated and the normally symmetric expression of Lunatic fringe, a component of the Notch pathway, showed a left-right bias in the last forming somite in 50% of all Ndr1/2-double embryos. In addition, Ndr1/2-double embryos developed a heart defect that manifests itself as pericardial edemas, obstructed heart tubes and arrest of cardiac looping. The resulting cardiac insufficiency is the likely cause of the lethality of Ndr1/2-double embryos around E10. Taken together, we show that NDR kinases compensate for each other in vivo in mouse embryos, explaining why mice deficient for either Ndr1 or Ndr2 are viable. Ndr1/2-double embryos show defects in somitogenesis and cardiac looping, which reveals their essential functions and shows that the NDR kinases are critically required during the early phase of organogenesis.

No MeSH data available.


Related in: MedlinePlus

NDR kinases are essential for growth, cardiac development and blood vessel remodeling from about embryonic day 8 onward in mouse embryos.(A, B) Bright field images of wild-type (A) and Ndr1/2-double  (B) littermates at E8.5. Both embryos are of the 6-somite stage. Note that the Ndr1/2-double  somites are small and irregularly shaped. Scale bars correspond to 500μm. (C) Average somite numbers of wild-type and Ndr1/2-double  littermates at E8.5. Data correspond to the analysis of a total of 15 litters and are blotted as box and whisker chart illustrating the distribution of somite numbers per litter and genotype. Average somite numbers are indicated. (D, E) Distribution of Shh (D) and T/brachyury (E) transcripts in wild-type (left) and Ndr1/2-double  littermate embryos (right) at E8.5. Four animals per genotype were analyzed, and all embryos displayed the staining shown in Fig 3D and 3E. (F, G, H) Bright field images of wild-type (F) and Ndr1/2-double  (G, H) littermate embryos at E9.5. 56 Ndr1/2-double  and 163 control embryos at E9.5 were analyzed. White arrow in H points to the pericardial edema. Scale bars correspond to 500μm. (I, J) Bright field images of the yolk sacs of wild-type (I) and Ndr1/2-double  (J) littermate embryos at E9.5. All Ndr1/2-double  yolk sacs (n = 56) displayed defective vascular development as illustrated in Fig 3J.
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pone.0136566.g003: NDR kinases are essential for growth, cardiac development and blood vessel remodeling from about embryonic day 8 onward in mouse embryos.(A, B) Bright field images of wild-type (A) and Ndr1/2-double (B) littermates at E8.5. Both embryos are of the 6-somite stage. Note that the Ndr1/2-double somites are small and irregularly shaped. Scale bars correspond to 500μm. (C) Average somite numbers of wild-type and Ndr1/2-double littermates at E8.5. Data correspond to the analysis of a total of 15 litters and are blotted as box and whisker chart illustrating the distribution of somite numbers per litter and genotype. Average somite numbers are indicated. (D, E) Distribution of Shh (D) and T/brachyury (E) transcripts in wild-type (left) and Ndr1/2-double littermate embryos (right) at E8.5. Four animals per genotype were analyzed, and all embryos displayed the staining shown in Fig 3D and 3E. (F, G, H) Bright field images of wild-type (F) and Ndr1/2-double (G, H) littermate embryos at E9.5. 56 Ndr1/2-double and 163 control embryos at E9.5 were analyzed. White arrow in H points to the pericardial edema. Scale bars correspond to 500μm. (I, J) Bright field images of the yolk sacs of wild-type (I) and Ndr1/2-double (J) littermate embryos at E9.5. All Ndr1/2-double yolk sacs (n = 56) displayed defective vascular development as illustrated in Fig 3J.

Mentions: To gain insight into the essential embryonic functions of NDR kinases, we analyzed Ndr1/2-double embryos. At embryonic day 10.5 (E10.5), Ndr1/2-double embryos suffered from severe growth retardation and were resorbed (Table 2; data not shown), indicating that NDR kinases are essential prior to this developmental period. At E10.5 all Ndr1/2-double embryos isolated were dead (Table 2). Analysis of younger embryos revealed viable Ndr1/2-double embryos at expected Mendelian ratio up to E9.5 (Table 2). However, already at E8.5 Ndr1/2-double embryos appeared smaller and developmentally delayed as judged by their somite numbers (Fig 3A, 3B and 3C). Wild-type littermates had on average ten somites, while Ndr1/2-double embryos had only six to seven somites at E8.5 (Fig 3C). Somites of Ndr1/2-double embryos appeared also smaller and less defined (Fig 3B).


NDR Kinases Are Essential for Somitogenesis and Cardiac Looping during Mouse Embryonic Development.

Schmitz-Rohmer D, Probst S, Yang ZZ, Laurent F, Stadler MB, Zuniga A, Zeller R, Hynx D, Hemmings BA, Hergovich A - PLoS ONE (2015)

NDR kinases are essential for growth, cardiac development and blood vessel remodeling from about embryonic day 8 onward in mouse embryos.(A, B) Bright field images of wild-type (A) and Ndr1/2-double  (B) littermates at E8.5. Both embryos are of the 6-somite stage. Note that the Ndr1/2-double  somites are small and irregularly shaped. Scale bars correspond to 500μm. (C) Average somite numbers of wild-type and Ndr1/2-double  littermates at E8.5. Data correspond to the analysis of a total of 15 litters and are blotted as box and whisker chart illustrating the distribution of somite numbers per litter and genotype. Average somite numbers are indicated. (D, E) Distribution of Shh (D) and T/brachyury (E) transcripts in wild-type (left) and Ndr1/2-double  littermate embryos (right) at E8.5. Four animals per genotype were analyzed, and all embryos displayed the staining shown in Fig 3D and 3E. (F, G, H) Bright field images of wild-type (F) and Ndr1/2-double  (G, H) littermate embryos at E9.5. 56 Ndr1/2-double  and 163 control embryos at E9.5 were analyzed. White arrow in H points to the pericardial edema. Scale bars correspond to 500μm. (I, J) Bright field images of the yolk sacs of wild-type (I) and Ndr1/2-double  (J) littermate embryos at E9.5. All Ndr1/2-double  yolk sacs (n = 56) displayed defective vascular development as illustrated in Fig 3J.
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pone.0136566.g003: NDR kinases are essential for growth, cardiac development and blood vessel remodeling from about embryonic day 8 onward in mouse embryos.(A, B) Bright field images of wild-type (A) and Ndr1/2-double (B) littermates at E8.5. Both embryos are of the 6-somite stage. Note that the Ndr1/2-double somites are small and irregularly shaped. Scale bars correspond to 500μm. (C) Average somite numbers of wild-type and Ndr1/2-double littermates at E8.5. Data correspond to the analysis of a total of 15 litters and are blotted as box and whisker chart illustrating the distribution of somite numbers per litter and genotype. Average somite numbers are indicated. (D, E) Distribution of Shh (D) and T/brachyury (E) transcripts in wild-type (left) and Ndr1/2-double littermate embryos (right) at E8.5. Four animals per genotype were analyzed, and all embryos displayed the staining shown in Fig 3D and 3E. (F, G, H) Bright field images of wild-type (F) and Ndr1/2-double (G, H) littermate embryos at E9.5. 56 Ndr1/2-double and 163 control embryos at E9.5 were analyzed. White arrow in H points to the pericardial edema. Scale bars correspond to 500μm. (I, J) Bright field images of the yolk sacs of wild-type (I) and Ndr1/2-double (J) littermate embryos at E9.5. All Ndr1/2-double yolk sacs (n = 56) displayed defective vascular development as illustrated in Fig 3J.
Mentions: To gain insight into the essential embryonic functions of NDR kinases, we analyzed Ndr1/2-double embryos. At embryonic day 10.5 (E10.5), Ndr1/2-double embryos suffered from severe growth retardation and were resorbed (Table 2; data not shown), indicating that NDR kinases are essential prior to this developmental period. At E10.5 all Ndr1/2-double embryos isolated were dead (Table 2). Analysis of younger embryos revealed viable Ndr1/2-double embryos at expected Mendelian ratio up to E9.5 (Table 2). However, already at E8.5 Ndr1/2-double embryos appeared smaller and developmentally delayed as judged by their somite numbers (Fig 3A, 3B and 3C). Wild-type littermates had on average ten somites, while Ndr1/2-double embryos had only six to seven somites at E8.5 (Fig 3C). Somites of Ndr1/2-double embryos appeared also smaller and less defined (Fig 3B).

Bottom Line: In addition, Ndr1/2-double embryos developed a heart defect that manifests itself as pericardial edemas, obstructed heart tubes and arrest of cardiac looping.The resulting cardiac insufficiency is the likely cause of the lethality of Ndr1/2-double embryos around E10.Ndr1/2-double embryos show defects in somitogenesis and cardiac looping, which reveals their essential functions and shows that the NDR kinases are critically required during the early phase of organogenesis.

View Article: PubMed Central - PubMed

Affiliation: Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.

ABSTRACT
Studies of mammalian tissue culture cells indicate that the conserved and distinct NDR isoforms, NDR1 and NDR2, play essential cell biological roles. However, mice lacking either Ndr1 or Ndr2 alone develop normally. Here, we studied the physiological consequences of inactivating both NDR1 and NDR2 in mice, showing that the lack of both Ndr1/Ndr2 (called Ndr1/2-double mutants) causes embryonic lethality. In support of compensatory roles for NDR1 and NDR2, total protein and activating phosphorylation levels of the remaining NDR isoform were elevated in mice lacking either Ndr1 or Ndr2. Mice retaining one single wild-type Ndr allele were viable and fertile. Ndr1/2-double embryos displayed multiple phenotypes causing a developmental delay from embryonic day E8.5 onwards. While NDR kinases are not required for notochord formation, the somites of Ndr1/2-double embryos were smaller, irregularly shaped and unevenly spaced along the anterior-posterior axis. Genes implicated in somitogenesis were down-regulated and the normally symmetric expression of Lunatic fringe, a component of the Notch pathway, showed a left-right bias in the last forming somite in 50% of all Ndr1/2-double embryos. In addition, Ndr1/2-double embryos developed a heart defect that manifests itself as pericardial edemas, obstructed heart tubes and arrest of cardiac looping. The resulting cardiac insufficiency is the likely cause of the lethality of Ndr1/2-double embryos around E10. Taken together, we show that NDR kinases compensate for each other in vivo in mouse embryos, explaining why mice deficient for either Ndr1 or Ndr2 are viable. Ndr1/2-double embryos show defects in somitogenesis and cardiac looping, which reveals their essential functions and shows that the NDR kinases are critically required during the early phase of organogenesis.

No MeSH data available.


Related in: MedlinePlus