Mediator subunit MED1 differentially modulates mutant thyroid hormone receptor intracellular dynamics in Resistance to Thyroid Hormone syndrome.

Thyroid hormone receptor (TR) controls the expression of thyroid hormone (T3)-responsive genes, while undergoing rapid nucleocytoplasmic shuttling. In Resistance to Thyroid Hormone syndrome (RTH), mutant TR fails to activate T3-dependent transcription. Previously, we showed that Mediator subunit 1 (MED1) plays a role in TR nuclear retention. Here, we investigated MED1's effect on RTH mutants using nucleocytoplasmic scoring and fluorescence recovery after photobleaching in transfected cells. MED1 overexpression and knockout did not change the nucleocytoplasmic distribution or intranuclear mobility of C392X and P398R TRα1 at physiological T3 levels. At elevated T3 levels, however, overexpression increased P398R's nuclear retention and MED1 knockout decreased P398R's and A263V's intranuclear mobility, while not impacting C392X. Although A263V TRα1-transfected cells had a high percentage of aggregates, MED1 rescued A263V's impaired intranuclear mobility, suggesting that MED1 ameliorates nonfunctional aggregates. Results correlate with clinical severity, suggesting that altered interaction between MED1 and TRα1 mutants contributes to RTH pathology.

NTN1 gene was risk to non-syndromic cleft lip only among Han Chinese population.

OBJECTIVE: Genome-wide association studies (GWAS) found NTN1, NOG and the region between CREBBP and ADCY9 were risks to non-syndromic cleft lip with or without cleft palate (NSCL/P). However, the association of single nucleotide polymorphisms (SNPs) in these genes with NSCL/P in Western China is unknown. SUBJECTS AND METHODS: We selected seven SNPs in NTN1, NOG and between CREBBP and ADCY9, and then performed transmission disequilibrium test (TDT), parent-of-origin effect and sliding window haplotype analysis to test the associations among 302 NSCL/P case-parent trios from Western Han Chinese. RESULTS: We found allele G at rs4791774 in NTN1 was significantly overtransmitted among non-syndromic cleft lip only (NSCLO) (p = 0.0067, OR = 1.79, 95% CI: 1.17-2.74); rs4791774 and rs9915089 tightly linked with each other among NSCL/P (D' = 0.87, r2  = 0.67) and haplotypes carrying the risk allele G at rs4791774 were always found to be overtransmitted from parents to cases. Motif analysis indicated that allele G at rs4791774 could greatly alter the affinity of Myc_disc7, so allele G at rs4791774 in NTN1 might modulate C-MYC transcription to participate in the aetiology of NSCLO. CONCLUSIONS: Our study suggested allele G at rs4791774 in NTN1 gene is risk of NSCLO, which could greatly increase the risk to have a baby with cleft.