Rett-causing mutations reveal two domains critical for MeCP2 function and for toxicity in MECP2 duplication syndrome mice

  1. Laura Dean Heckman
  2. Maria H Chahrour
  3. Huda Y Zoghbi  Is a corresponding author
  1. Baylor College of Medicine, United States
  2. Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, United States
  3. Harvard Medical School, United States
  4. Howard Hughes Medical Institute, Baylor College of Medicine, United States
7 figures

Figures

Generation of transgenic lines.

(A) Schematic representation of MeCP2-EGFP fusion protein, showing the methyl-CpG binding domain (MBD, blue), transcriptional repression domain (TRD, red), a cluster of basic amino acids (yellow), …

https://doi.org/10.7554/eLife.02676.003
R111G mice phenocopy the null mice whereas R111G Tg mice are indistinguishable from WT mice.

(A) Using a Kaplan–Meier survival curve, both WT (black, n = 11) and R111G Tg (blue, n = 10) have a normal lifespan, whereas R111G mice (green, n = 10) phenocopy the premature lethality of the null …

https://doi.org/10.7554/eLife.02676.004
R111G abolishes MeCP2 binding to methyl-CpGs but does not affect its ability to interact with known binding partners.

(A) MeCP2-R111G does not bind to methyl-CpGs in vivo. Immunofluorescence for endogenous MeCP2 (anti-MeCP2 antibody, red), the transgene (anti-GFP antibody, green), and heterochromatic foci (puncta …

https://doi.org/10.7554/eLife.02676.005
R306C mice have a milder phenotype than null mice.

(A) A Kaplan–Meier survival curve shows that WT (black, n = 28) and R306C Tg (blue, n = 22) mice have a normal lifespan, while R306C (green, n = 21) mice have a shortened lifespan with 50% lethality …

https://doi.org/10.7554/eLife.02676.006
R306C mice recapitulate many RTT phenotypes.

(AE) Behavioral tests were performed at 5 weeks of age to examine the R306C phenotype. At this age, WT (black, n = 18) and R306C Tg (blue, n = 17) mice are indistinguishable. Like the null mice …

https://doi.org/10.7554/eLife.02676.007
R306C does not affect methyl-CpG binding, but alters binding to a subset of known interactors.

(A) MeCP2-R306C binds methyl-CpGs in vivo. Immunofluorescence for endogenous MeCP2 (anti-MeCP2 antibody, red), the transgene (anti-GFP antibody, green), and heterochromatic foci (puncta within the …

https://doi.org/10.7554/eLife.02676.008
R306C decreases the affinity of the C-terminus of MeCP2 to DNA and reduces its DNA occupancy.

(A) An overview of the lifespans of RTT mouse models emphasizes the fact that the R306C missense mutation is more detrimental than an earlier truncation at G273X. Full-length MeCP2 (gray) with the …

https://doi.org/10.7554/eLife.02676.009

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