Limits...
Transcriptional regulation of the MET receptor tyrosine kinase gene by MeCP2 and sex-specific expression in autism and Rett syndrome.

Plummer JT, Evgrafov OV, Bergman MY, Friez M, Haiman CA, Levitt P, Aldinger KA - Transl Psychiatry (2013)

Bottom Line: The MET promoter SNV rs1858830 C 'low activity' allele is enriched in ASD, associated with reduced protein expression, and impacts functional and structural circuit connectivity in humans.We newly identified a sex-based reduction in MET expression, with male ASD cases, but not female ASD cases compared with sex-matched controls.The mechanisms underlying the pronounced reduction of MET in ASD and RTT temporal cortex are distinct and likely related to factors unique to each disorder, including a noted sex bias.

View Article: PubMed Central - PubMed

Affiliation: Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.

ABSTRACT
Single nucleotide variants (SNV) in the gene encoding the MET receptor tyrosine kinase have been associated with an increased risk for autism spectrum disorders (ASD). The MET promoter SNV rs1858830 C 'low activity' allele is enriched in ASD, associated with reduced protein expression, and impacts functional and structural circuit connectivity in humans. To gain insight into the transcriptional regulation of MET on ASD-risk etiology, we examined an interaction between the methyl CpG-binding protein 2 (MeCP2) and the MET 5' promoter region. Mutations in MeCP2 cause Rett syndrome (RTT), a predominantly female neurodevelopmental disorder sharing some ASD clinical symptoms. MeCP2 binds to a region of the MET promoter containing the ASD-risk SNV, and displays rs1858830 genotype-specific binding in human neural progenitor cells derived from the olfactory neuroepithelium. MeCP2 binding enhances MET expression in the presence of the rs1858830 C allele, but MET transcription is attenuated by RTT-specific mutations in MeCP2. In the postmortem temporal cortex, a region normally enriched in MET, gene expression is reduced dramatically in females with RTT, although not due to enrichment of the rs1858830 C 'low activity' allele. We newly identified a sex-based reduction in MET expression, with male ASD cases, but not female ASD cases compared with sex-matched controls. The experimental data reveal a prominent allele-specific regulation of MET transcription by MeCP2. The mechanisms underlying the pronounced reduction of MET in ASD and RTT temporal cortex are distinct and likely related to factors unique to each disorder, including a noted sex bias.

Show MeSH

Related in: MedlinePlus

Functional characterization of MeCP2 and MECP2 mutations on MET transcriptional activation. (a) Luciferase reporter assays demonstrate differential activation of the MET promoter by MeCP2. MET luciferase reporter constructs containing rs1858830 G or C were transiently transfected into HEK cells with or without addition of MECP2 cDNA. *P<0.001. (b) Schematic of the MeCP2 protein structure with common RTT-causing mutations (MBD; TRD, transcription repressor domain; NLS, nuclear localization signal). (c) Luciferase assays of MECP2 mutations cotransfected with MET promoter luciferase showed altered transcription compared with wild-type MECP2. (red line-rs1858830 C allele+WT MECP2; blue line-rs1858830 G allele+WT MECP2). *P<0.05 compared with rs1858830 allele (G or C respectively)+ WT MECP2. Fold of luciferase activation was calculated after normalization against an empty luciferase control vector. All transfections were performed in triplicate.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3818007&req=5

fig2: Functional characterization of MeCP2 and MECP2 mutations on MET transcriptional activation. (a) Luciferase reporter assays demonstrate differential activation of the MET promoter by MeCP2. MET luciferase reporter constructs containing rs1858830 G or C were transiently transfected into HEK cells with or without addition of MECP2 cDNA. *P<0.001. (b) Schematic of the MeCP2 protein structure with common RTT-causing mutations (MBD; TRD, transcription repressor domain; NLS, nuclear localization signal). (c) Luciferase assays of MECP2 mutations cotransfected with MET promoter luciferase showed altered transcription compared with wild-type MECP2. (red line-rs1858830 C allele+WT MECP2; blue line-rs1858830 G allele+WT MECP2). *P<0.05 compared with rs1858830 allele (G or C respectively)+ WT MECP2. Fold of luciferase activation was calculated after normalization against an empty luciferase control vector. All transfections were performed in triplicate.

Mentions: To determine whether the rs1858830 SNV influences MeCP2 transcriptional regulation of MET, we transfected two luciferase reporter constructs containing 663 bp of the MET promoter (Figure 1a), differing only at the rs1858830 nucleotide, together with MECP2 cDNA into HEK cells. First, we replicated previous findings10 that the reporter construct containing the G allele generates greater luciferase activity compared with the construct containing the C allele (P=0.022; Figure 2a). Next, cells were cotransfected with MECP2 cDNA and each of the two MET promoter constructs. Surprisingly, greater luciferase activity was detected when the C allele construct was cotransfected with MECP2 compared with the C allele alone (P=0.0002). No significant difference in luciferase activity was detected when the G allele was cotransfected with MECP2 compared with the G allele alone (P=0.099). In the presence of MeCP2, the C allele also showed greater transcriptional activity than the G allele (P=0.0001). These data indicate that the rs1858830 C allele can directly modulate MeCP2 activation of MET transcription.


Transcriptional regulation of the MET receptor tyrosine kinase gene by MeCP2 and sex-specific expression in autism and Rett syndrome.

Plummer JT, Evgrafov OV, Bergman MY, Friez M, Haiman CA, Levitt P, Aldinger KA - Transl Psychiatry (2013)

Functional characterization of MeCP2 and MECP2 mutations on MET transcriptional activation. (a) Luciferase reporter assays demonstrate differential activation of the MET promoter by MeCP2. MET luciferase reporter constructs containing rs1858830 G or C were transiently transfected into HEK cells with or without addition of MECP2 cDNA. *P<0.001. (b) Schematic of the MeCP2 protein structure with common RTT-causing mutations (MBD; TRD, transcription repressor domain; NLS, nuclear localization signal). (c) Luciferase assays of MECP2 mutations cotransfected with MET promoter luciferase showed altered transcription compared with wild-type MECP2. (red line-rs1858830 C allele+WT MECP2; blue line-rs1858830 G allele+WT MECP2). *P<0.05 compared with rs1858830 allele (G or C respectively)+ WT MECP2. Fold of luciferase activation was calculated after normalization against an empty luciferase control vector. All transfections were performed in triplicate.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3818007&req=5

fig2: Functional characterization of MeCP2 and MECP2 mutations on MET transcriptional activation. (a) Luciferase reporter assays demonstrate differential activation of the MET promoter by MeCP2. MET luciferase reporter constructs containing rs1858830 G or C were transiently transfected into HEK cells with or without addition of MECP2 cDNA. *P<0.001. (b) Schematic of the MeCP2 protein structure with common RTT-causing mutations (MBD; TRD, transcription repressor domain; NLS, nuclear localization signal). (c) Luciferase assays of MECP2 mutations cotransfected with MET promoter luciferase showed altered transcription compared with wild-type MECP2. (red line-rs1858830 C allele+WT MECP2; blue line-rs1858830 G allele+WT MECP2). *P<0.05 compared with rs1858830 allele (G or C respectively)+ WT MECP2. Fold of luciferase activation was calculated after normalization against an empty luciferase control vector. All transfections were performed in triplicate.
Mentions: To determine whether the rs1858830 SNV influences MeCP2 transcriptional regulation of MET, we transfected two luciferase reporter constructs containing 663 bp of the MET promoter (Figure 1a), differing only at the rs1858830 nucleotide, together with MECP2 cDNA into HEK cells. First, we replicated previous findings10 that the reporter construct containing the G allele generates greater luciferase activity compared with the construct containing the C allele (P=0.022; Figure 2a). Next, cells were cotransfected with MECP2 cDNA and each of the two MET promoter constructs. Surprisingly, greater luciferase activity was detected when the C allele construct was cotransfected with MECP2 compared with the C allele alone (P=0.0002). No significant difference in luciferase activity was detected when the G allele was cotransfected with MECP2 compared with the G allele alone (P=0.099). In the presence of MeCP2, the C allele also showed greater transcriptional activity than the G allele (P=0.0001). These data indicate that the rs1858830 C allele can directly modulate MeCP2 activation of MET transcription.

Bottom Line: The MET promoter SNV rs1858830 C 'low activity' allele is enriched in ASD, associated with reduced protein expression, and impacts functional and structural circuit connectivity in humans.We newly identified a sex-based reduction in MET expression, with male ASD cases, but not female ASD cases compared with sex-matched controls.The mechanisms underlying the pronounced reduction of MET in ASD and RTT temporal cortex are distinct and likely related to factors unique to each disorder, including a noted sex bias.

View Article: PubMed Central - PubMed

Affiliation: Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.

ABSTRACT
Single nucleotide variants (SNV) in the gene encoding the MET receptor tyrosine kinase have been associated with an increased risk for autism spectrum disorders (ASD). The MET promoter SNV rs1858830 C 'low activity' allele is enriched in ASD, associated with reduced protein expression, and impacts functional and structural circuit connectivity in humans. To gain insight into the transcriptional regulation of MET on ASD-risk etiology, we examined an interaction between the methyl CpG-binding protein 2 (MeCP2) and the MET 5' promoter region. Mutations in MeCP2 cause Rett syndrome (RTT), a predominantly female neurodevelopmental disorder sharing some ASD clinical symptoms. MeCP2 binds to a region of the MET promoter containing the ASD-risk SNV, and displays rs1858830 genotype-specific binding in human neural progenitor cells derived from the olfactory neuroepithelium. MeCP2 binding enhances MET expression in the presence of the rs1858830 C allele, but MET transcription is attenuated by RTT-specific mutations in MeCP2. In the postmortem temporal cortex, a region normally enriched in MET, gene expression is reduced dramatically in females with RTT, although not due to enrichment of the rs1858830 C 'low activity' allele. We newly identified a sex-based reduction in MET expression, with male ASD cases, but not female ASD cases compared with sex-matched controls. The experimental data reveal a prominent allele-specific regulation of MET transcription by MeCP2. The mechanisms underlying the pronounced reduction of MET in ASD and RTT temporal cortex are distinct and likely related to factors unique to each disorder, including a noted sex bias.

Show MeSH
Related in: MedlinePlus