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PTBP1 is required for embryonic development before gastrulation.

Suckale J, Wendling O, Masjkur J, Jäger M, Münster C, Anastassiadis K, Stewart AF, Solimena M - PLoS ONE (2011)

Bottom Line: Embryos lacking PTBP1 did not display differentiation into the 3 germ layers and cavitation of the epiblast, which are hallmarks of gastrulation.We conclude that PTBP1 is not required for the earliest isovolumetric divisions and differentiation steps of the zygote up to the formation of the blastocyst.However, further post-implantation development requires PTBP1 and stalls in homozygous animals with a phenotype of dramatically reduced size and aberration in embryonic and extra-embryonic structures.

View Article: PubMed Central - PubMed

Affiliation: Molecular Diabetology, Paul Langerhans Institute Dresden, School of Medicine and University Clinic Carl Gustav Carus, Dresden University of Technology, Dresden, Germany.

ABSTRACT
Polypyrimidine-tract binding protein 1 (PTBP1) is an important cellular regulator of messenger RNAs influencing the alternative splicing profile of a cell as well as its mRNA stability, location and translation. In addition, it is diverted by some viruses to facilitate their replication. Here, we used a novel PTBP1 knockout mouse to analyse the tissue expression pattern of PTBP1 as well as the effect of its complete removal during development. We found evidence of strong PTBP1 expression in embryonic stem cells and throughout embryonic development, especially in the developing brain and spinal cord, the olfactory and auditory systems, the heart, the liver, the kidney, the brown fat and cartilage primordia. This widespread distribution points towards a role of PTBP1 during embryonic development. Homozygous offspring, identified by PCR and immunofluorescence, were able to implant but were arrested or retarded in growth. At day 7.5 of embryonic development (E7.5) the mutants were about 5x smaller than the control littermates and the gap in body size widened with time. At mid-gestation, all homozygous embryos were resorbed/degraded. No homozygous mice were genotyped at E12 and the age of weaning. Embryos lacking PTBP1 did not display differentiation into the 3 germ layers and cavitation of the epiblast, which are hallmarks of gastrulation. In addition, homozygous mutants displayed malformed ectoplacental cones and yolk sacs, both early supportive structure of the embryo proper. We conclude that PTBP1 is not required for the earliest isovolumetric divisions and differentiation steps of the zygote up to the formation of the blastocyst. However, further post-implantation development requires PTBP1 and stalls in homozygous animals with a phenotype of dramatically reduced size and aberration in embryonic and extra-embryonic structures.

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Related in: MedlinePlus

Deletion of PTBP1 leads to the absence of T/brachyury.The figure compares RT PCR results from normal and mutant embryos for the presence of a gastrulation marker and a control. RNA purified from large (L) and small (S) embryos was used as template for reverse transcriptase (RT) PCR amplification of the primitive streak marker T/brachyury and of a LacZ control to ensure successful RNA purification. None of the small PTBP1 KO homozygous embryos showed the presence of T mRNA while positive for the control RT PCR.
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pone-0016992-g006: Deletion of PTBP1 leads to the absence of T/brachyury.The figure compares RT PCR results from normal and mutant embryos for the presence of a gastrulation marker and a control. RNA purified from large (L) and small (S) embryos was used as template for reverse transcriptase (RT) PCR amplification of the primitive streak marker T/brachyury and of a LacZ control to ensure successful RNA purification. None of the small PTBP1 KO homozygous embryos showed the presence of T mRNA while positive for the control RT PCR.

Mentions: In normal mouse embryos gastrulation begins at ∼E6.5 with the formation of the primitive streak in the posterior side of the hollowed epiblast. Cells separate into the 3 germ layers. Most embryos were so malformed that early cell types like ectoderm and endoderm could not be discerned (Figure 4b, 5). Only very few homozygous embryos showed partial separation of cell layers like KO1 in Figure 4b. To further investigate the molecular underpinning of development in the mutants, we performed RT PCR for T/brachyury on mutant versus control embryos. T is an embryonic transcription factor expressed in the primitive streak during gastrulation. T was consistently detected in normal embryos but absent in all small mutant embryos while a control RT PCR was positive for all samples (Figure 6).


PTBP1 is required for embryonic development before gastrulation.

Suckale J, Wendling O, Masjkur J, Jäger M, Münster C, Anastassiadis K, Stewart AF, Solimena M - PLoS ONE (2011)

Deletion of PTBP1 leads to the absence of T/brachyury.The figure compares RT PCR results from normal and mutant embryos for the presence of a gastrulation marker and a control. RNA purified from large (L) and small (S) embryos was used as template for reverse transcriptase (RT) PCR amplification of the primitive streak marker T/brachyury and of a LacZ control to ensure successful RNA purification. None of the small PTBP1 KO homozygous embryos showed the presence of T mRNA while positive for the control RT PCR.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3040740&req=5

pone-0016992-g006: Deletion of PTBP1 leads to the absence of T/brachyury.The figure compares RT PCR results from normal and mutant embryos for the presence of a gastrulation marker and a control. RNA purified from large (L) and small (S) embryos was used as template for reverse transcriptase (RT) PCR amplification of the primitive streak marker T/brachyury and of a LacZ control to ensure successful RNA purification. None of the small PTBP1 KO homozygous embryos showed the presence of T mRNA while positive for the control RT PCR.
Mentions: In normal mouse embryos gastrulation begins at ∼E6.5 with the formation of the primitive streak in the posterior side of the hollowed epiblast. Cells separate into the 3 germ layers. Most embryos were so malformed that early cell types like ectoderm and endoderm could not be discerned (Figure 4b, 5). Only very few homozygous embryos showed partial separation of cell layers like KO1 in Figure 4b. To further investigate the molecular underpinning of development in the mutants, we performed RT PCR for T/brachyury on mutant versus control embryos. T is an embryonic transcription factor expressed in the primitive streak during gastrulation. T was consistently detected in normal embryos but absent in all small mutant embryos while a control RT PCR was positive for all samples (Figure 6).

Bottom Line: Embryos lacking PTBP1 did not display differentiation into the 3 germ layers and cavitation of the epiblast, which are hallmarks of gastrulation.We conclude that PTBP1 is not required for the earliest isovolumetric divisions and differentiation steps of the zygote up to the formation of the blastocyst.However, further post-implantation development requires PTBP1 and stalls in homozygous animals with a phenotype of dramatically reduced size and aberration in embryonic and extra-embryonic structures.

View Article: PubMed Central - PubMed

Affiliation: Molecular Diabetology, Paul Langerhans Institute Dresden, School of Medicine and University Clinic Carl Gustav Carus, Dresden University of Technology, Dresden, Germany.

ABSTRACT
Polypyrimidine-tract binding protein 1 (PTBP1) is an important cellular regulator of messenger RNAs influencing the alternative splicing profile of a cell as well as its mRNA stability, location and translation. In addition, it is diverted by some viruses to facilitate their replication. Here, we used a novel PTBP1 knockout mouse to analyse the tissue expression pattern of PTBP1 as well as the effect of its complete removal during development. We found evidence of strong PTBP1 expression in embryonic stem cells and throughout embryonic development, especially in the developing brain and spinal cord, the olfactory and auditory systems, the heart, the liver, the kidney, the brown fat and cartilage primordia. This widespread distribution points towards a role of PTBP1 during embryonic development. Homozygous offspring, identified by PCR and immunofluorescence, were able to implant but were arrested or retarded in growth. At day 7.5 of embryonic development (E7.5) the mutants were about 5x smaller than the control littermates and the gap in body size widened with time. At mid-gestation, all homozygous embryos were resorbed/degraded. No homozygous mice were genotyped at E12 and the age of weaning. Embryos lacking PTBP1 did not display differentiation into the 3 germ layers and cavitation of the epiblast, which are hallmarks of gastrulation. In addition, homozygous mutants displayed malformed ectoplacental cones and yolk sacs, both early supportive structure of the embryo proper. We conclude that PTBP1 is not required for the earliest isovolumetric divisions and differentiation steps of the zygote up to the formation of the blastocyst. However, further post-implantation development requires PTBP1 and stalls in homozygous animals with a phenotype of dramatically reduced size and aberration in embryonic and extra-embryonic structures.

Show MeSH
Related in: MedlinePlus