The development of mature B and T cells in the lymphoid system involves a series of molecular decisions that culminate in the expression of a single antigen receptor on the cell surface, a phenomenon termed allelic exclusion. While feedback inhibition of the recombinase-activation gene proteins evidently plays an important role in the maintenance of allelic exclusion, the initial restriction of rearrangement to only one allele in each cell seems to be achieved through monoallelic epigenetic changes. Epigenetic mechanisms involved in the establishment of allelic exclusion also play a central role in other types of monoallelic expression, including X-chromosome inactivation in female cells, and parental imprinting. In all three systems, the inequality of the two alleles seems to be achieved mainly by differential DNA methylation, asynchronous DNA replication, differential chromatin modifications, unequal nuclear localization, and non-coding RNA. In this review, we discuss the unifying features among these monoallelically expressed systems and the unique characteristics displayed by each of them.
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http://dx.doi.org/10.1111/j.0105-2896.2004.00158.x | DOI Listing |
Environ Pollut
January 2025
Center for Endemic Disease Control, Chinese Center for Disease Control and Prevention, Harbin Medical University, Harbin, People's Republic of China; NHC Key Laboratory of Etiology and Epidemiology(Harbin Medical University); Joint Key Laboratory of Endemic Diseases(Harbin Medical University, Guizhou Medical University, Xi'an Jiaotong University); Center for Chronic Disease Prevention and Control, Harbin Medical University, Harbin, People's Republic of China. Electronic address:
Background: Skeletal fluorosis is a chronic metabolic bone disease caused by excessive accumulation of fluoride in the bones. Previous studies have found that when the intake of tea fluoride is similar, the prevalence of skeletal fluorosis varies greatly among different ethnic groups, which may be related to different genetic backgrounds. Single nucleotide polymorphisms (SNPs) of estrogen receptor 1 (ESR1) and collagen type 1 α1 (COL1A1) were strongly associated with bone metabolism as well as bone growth and development, but their association with the risk of skeletal fluorosis has not been reported.
View Article and Find Full Text PDFBiology (Basel)
November 2024
Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia.
The aim of this work was to select InDel markers sufficient for human identification and to create a routine method for their genotyping. We analyzed the allele distribution of all known InDels in European, East Asian, South Asian, African, and American populations and selected markers whose minor allele frequency, MAF, was ≥ 0.30.
View Article and Find Full Text PDFSci Rep
December 2024
Department of Forensic Medicine, Guizhou Medical University, Guiyang, 550025, China.
Multi-insertion/deletion polymorphisms (Multi-InDels), as the novel genetic markers, show great potential in forensic research. Whereas, forensic researchers mainly focus on the multi-InDels on the autosomes, which can provide relatively limited information in some complex paternity cases. In this study, a novel X chromosomal multi-InDel multiplex amplification system was designed, containing 22 multi-InDels and one STR locus on the X chromosome.
View Article and Find Full Text PDFPLoS One
December 2024
Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, United States of America.
Environmental contamination can have lasting impacts on surrounding communities, though the long-term impacts can be difficult to ascertain. The disaster at the Chornobyl Nuclear Power Plant in 1986 and subsequent remediation efforts resulted in contamination of the local environment with radioactive material, heavy metals, and additional environmental toxicants. Many of these are mutagenic in nature, and the full effect of these exposures on local flora and fauna has yet to be understood.
View Article and Find Full Text PDFJ Clin Immunol
December 2024
Department of Human Genetics, Research Institute, National Center for Global Health and Medicine, Tokyo, 162-8655, Japan.
Anterior gradient 2 (AGR2) is a protein disulfide isomerase that is important for protein processing in the endoplasmic reticulum and is essential for mucin production in the digestive and respiratory tracts. Bi-allelic AGR2 variants were recently found to cause recurrent respiratory infections and failure to thrive with or without diarrhea (RIFTD; MIM # 620233), although the mechanisms behind this condition remain unclear. To date, at least 15 patients with homozygous AGR2 variants have been reported.
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