The three-dimensional (3D) organization of the genome is important for chromatin regulation. This organization is nonrandom and appears to be tightly correlated with or regulated by chromatin state and scaffolding proteins. To understand how specific DNA and chromatin elements contribute to the functional organization of the genome, we developed a new tool-the tagged chromosomal insertion site (TCIS) system-to identify and study minimal DNA sequences that drive nuclear compartmentalization and applied this system to specifically study the role of cis elements in targeting DNA to the nuclear lamina. The TCIS system allows Cre-recombinase-mediated site-directed integration of any DNA fragment into a locus tagged with lacO arrays, thus enabling both functional molecular studies and positional analysis of the altered locus. This system can be used to study the minimal DNA sequences that target the nuclear periphery (or other nuclear compartments), allowing researchers to understand how genome-wide results obtained, for example, by DNA adenine methyltransferase identification, chromosome conformation capture (HiC), or related methods, connect to the actual organization of DNA and chromosomes at the single-cell level. Finally, TCIS allows one to test roles for specific proteins in chromatin reorganization and to determine how changes in nuclear environment affect chromatin state and gene regulation at a single locus.
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http://dx.doi.org/10.1016/bs.mie.2015.09.028 | DOI Listing |
Elife
January 2025
Department of Molecular and Cell Biology, Berkeley, United States.
Type II nuclear receptors (T2NRs) require heterodimerization with a common partner, the retinoid X receptor (RXR), to bind cognate DNA recognition sites in chromatin. Based on previous biochemical and overexpression studies, binding of T2NRs to chromatin is proposed to be regulated by competition for a limiting pool of the core RXR subunit. However, this mechanism has not yet been tested for endogenous proteins in live cells.
View Article and Find Full Text PDFNat Commun
January 2025
Friedrich Miescher Institute for Biomedical Research, Fabrikstrasse 24, 4056, Basel, Switzerland.
In the germ line and during early embryogenesis, DNA methylation (DNAme) undergoes global erasure and re-establishment to support germ cell and embryonic development. While DNAme acquisition during male germ cell development is essential for setting genomic DNA methylation imprints, other intergenerational roles for paternal DNAme in defining embryonic chromatin are unknown. Through conditional gene deletion of the de novo DNA methyltransferases Dnmt3a and/or Dnmt3b, we observe that DNMT3A primarily safeguards against DNA hypomethylation in undifferentiated spermatogonia, while DNMT3B catalyzes de novo DNAme during spermatogonial differentiation.
View Article and Find Full Text PDFMicromachines (Basel)
December 2024
Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013, Taiwan.
(1) Background: Fetal chromosomal examination is a critical component of modern prenatal testing. Traditionally, maternal serum biomarkers such as free β-human chorionic gonadotropin (Free β-HCG) and pregnancy-associated plasma protein A (PAPPA) have been employed for screening, achieving a detection rate of approximately 90% for fetuses with Down syndrome, albeit with a false positive rate of 5%. While amniocentesis remains the gold standard for the prenatal diagnosis of chromosomal abnormalities, including Down syndrome and Edwards syndrome, its invasive nature carries a significant risk of complications, such as infection, preterm labor, or miscarriage, occurring at a rate of 7 per 1000 procedures.
View Article and Find Full Text PDFNat Commun
December 2024
State Key Laboratory for Animal Disease Control and Prevention, Center for Emerging and Zoonotic Diseases, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.
The anthroponotic Cryptosporidium hominis differs from the zoonotic C. parvum in its lack of infectivity to animals, but several divergent subtypes have recently been found in nonhuman primates and equines. Here, we sequence 17 animal C.
View Article and Find Full Text PDFTheor Appl Genet
December 2024
Key Laboratory of Germplasm Enhancement, Physiology and Ecology of Food Crops in Cold Region, Ministry of Education, Northeast Agricultural University, Harbin, 150030, China.
Integrated genome-wide association study and linkage mapping revealed genetic basis of alkalinity tolerance during rice germination. The key gene OsWRKY49 was further verified in transgenic plants. With the widespread use of the rice direct seeding cultivation model, improving the tolerance of rice varieties to salinity-alkalinity at the germination stage has become increasingly important.
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