Temporal shift in methyl-CpG binding protein 2 expression in a mouse model of Rett syndrome

B. M. Metcalf, B. C. Mullaney, Michael V Johnston, Mary E Blue

Research output: Contribution to journalArticle

Abstract

Rett syndrome is an X-linked neurodevelopmental disorder caused by mutations in methyl-CpG binding protein 2. Females with identical mutations in the methyl-CpG binding protein 2 gene can display varying severity of symptoms, suggesting that other factors such as X-chromosome inactivation affect phenotypic expression in Rett syndrome. Although X-chromosome inactivation is random and balanced in the blood and brain of the majority of girls with classic Rett syndrome, skewing in the ratio of expression of the mutant methyl-CpG binding protein 2-X to the wildtype-X affects the severity of symptoms. In this study, the pattern of immunostaining for methyl-CpG binding protein 2 was compared with that of neuronal nuclei specific protein, a pan-neuronal marker, to assess X-chromosome inactivation in a Rett syndrome mouse model. The number of cortical neurons and cortical volume were assessed by unbiased stereological measurements in younger adult (7-9 week old) wildtype (wildtype/methyl-CpG binding protein 2+/+), female heterozygous (heterozygous/methyl-CpG binding protein 2+/-), and null (methyl-CpG binding protein 2-/y) male mice and in older adult (24-95 week old) wildtype and heterozygous mice. The results showed that the number of neuronal nuclei specific protein-positive cells and cortical volume did not differ by genotype or age. However, younger adult heterozygous mice had significantly fewer methyl-CpG binding protein 2 cells and the pattern of methyl-CpG binding protein 2 staining was less distinct than in younger adult wildtype mice. However, in older adult heterozygous mice, the number and pattern of methyl-CpG binding protein 2-expressing neurons were similar to the wildtype. The ratio of methyl-CpG binding protein 2 to neuronal nuclei specific protein-stained neurons, a potential measure of X-chromosome inactivation, was close to 50% in the younger adult heterozygous mice, but nearly 70% in the older adult heterozygous mice. These results suggest that X-chromosome inactivation status changes with age. Such a change may underlie the more stable neurological function in older Rett syndrome patients.

Original languageEnglish (US)
Pages (from-to)1449-1460
Number of pages12
JournalNeuroscience
Volume139
Issue number4
DOIs
StatePublished - 2006

Fingerprint

Methyl-CpG-Binding Protein 2
Rett Syndrome
X Chromosome Inactivation
Young Adult
Neurons
Mutation
Proteins
Cell Size

Keywords

  • cerebral cortex
  • methyl CpG-binding protein 2
  • stereology
  • X-inactivation

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

Temporal shift in methyl-CpG binding protein 2 expression in a mouse model of Rett syndrome. / Metcalf, B. M.; Mullaney, B. C.; Johnston, Michael V; Blue, Mary E.

In: Neuroscience, Vol. 139, No. 4, 2006, p. 1449-1460.

Research output: Contribution to journalArticle

@article{b36e8049b818434e90657fecb0152446,
title = "Temporal shift in methyl-CpG binding protein 2 expression in a mouse model of Rett syndrome",
abstract = "Rett syndrome is an X-linked neurodevelopmental disorder caused by mutations in methyl-CpG binding protein 2. Females with identical mutations in the methyl-CpG binding protein 2 gene can display varying severity of symptoms, suggesting that other factors such as X-chromosome inactivation affect phenotypic expression in Rett syndrome. Although X-chromosome inactivation is random and balanced in the blood and brain of the majority of girls with classic Rett syndrome, skewing in the ratio of expression of the mutant methyl-CpG binding protein 2-X to the wildtype-X affects the severity of symptoms. In this study, the pattern of immunostaining for methyl-CpG binding protein 2 was compared with that of neuronal nuclei specific protein, a pan-neuronal marker, to assess X-chromosome inactivation in a Rett syndrome mouse model. The number of cortical neurons and cortical volume were assessed by unbiased stereological measurements in younger adult (7-9 week old) wildtype (wildtype/methyl-CpG binding protein 2+/+), female heterozygous (heterozygous/methyl-CpG binding protein 2+/-), and null (methyl-CpG binding protein 2-/y) male mice and in older adult (24-95 week old) wildtype and heterozygous mice. The results showed that the number of neuronal nuclei specific protein-positive cells and cortical volume did not differ by genotype or age. However, younger adult heterozygous mice had significantly fewer methyl-CpG binding protein 2 cells and the pattern of methyl-CpG binding protein 2 staining was less distinct than in younger adult wildtype mice. However, in older adult heterozygous mice, the number and pattern of methyl-CpG binding protein 2-expressing neurons were similar to the wildtype. The ratio of methyl-CpG binding protein 2 to neuronal nuclei specific protein-stained neurons, a potential measure of X-chromosome inactivation, was close to 50{\%} in the younger adult heterozygous mice, but nearly 70{\%} in the older adult heterozygous mice. These results suggest that X-chromosome inactivation status changes with age. Such a change may underlie the more stable neurological function in older Rett syndrome patients.",
keywords = "cerebral cortex, methyl CpG-binding protein 2, stereology, X-inactivation",
author = "Metcalf, {B. M.} and Mullaney, {B. C.} and Johnston, {Michael V} and Blue, {Mary E}",
year = "2006",
doi = "10.1016/j.neuroscience.2006.01.060",
language = "English (US)",
volume = "139",
pages = "1449--1460",
journal = "Neuroscience",
issn = "0306-4522",
publisher = "Elsevier Limited",
number = "4",

}

TY - JOUR

T1 - Temporal shift in methyl-CpG binding protein 2 expression in a mouse model of Rett syndrome

AU - Metcalf, B. M.

AU - Mullaney, B. C.

AU - Johnston, Michael V

AU - Blue, Mary E

PY - 2006

Y1 - 2006

N2 - Rett syndrome is an X-linked neurodevelopmental disorder caused by mutations in methyl-CpG binding protein 2. Females with identical mutations in the methyl-CpG binding protein 2 gene can display varying severity of symptoms, suggesting that other factors such as X-chromosome inactivation affect phenotypic expression in Rett syndrome. Although X-chromosome inactivation is random and balanced in the blood and brain of the majority of girls with classic Rett syndrome, skewing in the ratio of expression of the mutant methyl-CpG binding protein 2-X to the wildtype-X affects the severity of symptoms. In this study, the pattern of immunostaining for methyl-CpG binding protein 2 was compared with that of neuronal nuclei specific protein, a pan-neuronal marker, to assess X-chromosome inactivation in a Rett syndrome mouse model. The number of cortical neurons and cortical volume were assessed by unbiased stereological measurements in younger adult (7-9 week old) wildtype (wildtype/methyl-CpG binding protein 2+/+), female heterozygous (heterozygous/methyl-CpG binding protein 2+/-), and null (methyl-CpG binding protein 2-/y) male mice and in older adult (24-95 week old) wildtype and heterozygous mice. The results showed that the number of neuronal nuclei specific protein-positive cells and cortical volume did not differ by genotype or age. However, younger adult heterozygous mice had significantly fewer methyl-CpG binding protein 2 cells and the pattern of methyl-CpG binding protein 2 staining was less distinct than in younger adult wildtype mice. However, in older adult heterozygous mice, the number and pattern of methyl-CpG binding protein 2-expressing neurons were similar to the wildtype. The ratio of methyl-CpG binding protein 2 to neuronal nuclei specific protein-stained neurons, a potential measure of X-chromosome inactivation, was close to 50% in the younger adult heterozygous mice, but nearly 70% in the older adult heterozygous mice. These results suggest that X-chromosome inactivation status changes with age. Such a change may underlie the more stable neurological function in older Rett syndrome patients.

AB - Rett syndrome is an X-linked neurodevelopmental disorder caused by mutations in methyl-CpG binding protein 2. Females with identical mutations in the methyl-CpG binding protein 2 gene can display varying severity of symptoms, suggesting that other factors such as X-chromosome inactivation affect phenotypic expression in Rett syndrome. Although X-chromosome inactivation is random and balanced in the blood and brain of the majority of girls with classic Rett syndrome, skewing in the ratio of expression of the mutant methyl-CpG binding protein 2-X to the wildtype-X affects the severity of symptoms. In this study, the pattern of immunostaining for methyl-CpG binding protein 2 was compared with that of neuronal nuclei specific protein, a pan-neuronal marker, to assess X-chromosome inactivation in a Rett syndrome mouse model. The number of cortical neurons and cortical volume were assessed by unbiased stereological measurements in younger adult (7-9 week old) wildtype (wildtype/methyl-CpG binding protein 2+/+), female heterozygous (heterozygous/methyl-CpG binding protein 2+/-), and null (methyl-CpG binding protein 2-/y) male mice and in older adult (24-95 week old) wildtype and heterozygous mice. The results showed that the number of neuronal nuclei specific protein-positive cells and cortical volume did not differ by genotype or age. However, younger adult heterozygous mice had significantly fewer methyl-CpG binding protein 2 cells and the pattern of methyl-CpG binding protein 2 staining was less distinct than in younger adult wildtype mice. However, in older adult heterozygous mice, the number and pattern of methyl-CpG binding protein 2-expressing neurons were similar to the wildtype. The ratio of methyl-CpG binding protein 2 to neuronal nuclei specific protein-stained neurons, a potential measure of X-chromosome inactivation, was close to 50% in the younger adult heterozygous mice, but nearly 70% in the older adult heterozygous mice. These results suggest that X-chromosome inactivation status changes with age. Such a change may underlie the more stable neurological function in older Rett syndrome patients.

KW - cerebral cortex

KW - methyl CpG-binding protein 2

KW - stereology

KW - X-inactivation

UR - http://www.scopus.com/inward/record.url?scp=33646164398&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33646164398&partnerID=8YFLogxK

U2 - 10.1016/j.neuroscience.2006.01.060

DO - 10.1016/j.neuroscience.2006.01.060

M3 - Article

C2 - 16549272

AN - SCOPUS:33646164398

VL - 139

SP - 1449

EP - 1460

JO - Neuroscience

JF - Neuroscience

SN - 0306-4522

IS - 4

ER -