Research progress on the role of lncRNA, circular RNA, and microRNA networks in regulating ferroptosis in osteosarcoma.

Noncoding RNAs (ncRNAs) do not participate in protein-coding. Ferroptosis is a newly discovered form of cell death mediated by reactive oxygen species and lipid peroxidation. Recent studies have shown that ncRNAs such as microRNAs, long noncoding RNAs, circular RNAs, and ferroptosis are involved in the occurrence and development of osteosarcoma (OS).

A prominent gene activation role for C-terminal binding protein in mediating PcG/trxG proteins through Hox gene regulation.

The evolutionarily conserved C-terminal binding protein (CtBP) has been well characterized as a transcriptional co-repressor. Herein, we report a previously unreported function for CtBP, showing that lowering CtBP dosage genetically suppresses Polycomb group (PcG) loss-of-function phenotypes while enhancing that of trithorax group (trxG) in Drosophila, suggesting that the role of CtBP in gene activation is more pronounced in fly development than previously thought. In fly cells, we show that CtBP is required for the derepression of the most direct PcG target genes, which are highly enriched by homeobox transcription factors, including Hox genes.

Stuxnet Facilitates the Degradation of Polycomb Protein during Development.

Polycomb-group (PcG) proteins function to ensure correct deployment of developmental programs by epigenetically repressing target gene expression. Despite the importance, few studies have been focused on the regulation of PcG activity itself. Here, we report a Drosophila gene, stuxnet (stx), that controls Pc protein stability.

Polycomb inhibits histone acetylation by CBP by binding directly to its catalytic domain.

Drosophila Polycomb (PC), a subunit of Polycomb repressive complex 1 (PRC1), is well known for its role in maintaining repression of the homeotic genes and many others and for its binding to trimethylated histone H3 on Lys 27 (H3K27me3) via its chromodomain. Here, we identify a novel activity of PC: inhibition of the histone acetylation activity of CREB-binding protein (CBP). We show that PC and its mammalian CBX orthologs interact directly with the histone acetyltransferase (HAT) domain of CBP, binding to the previously identified autoregulatory loop, whose autoacetylation greatly enhances HAT activity.

Trithorax monomethylates histone H3K4 and interacts directly with CBP to promote H3K27 acetylation and antagonize Polycomb silencing.

Trithorax (TRX) antagonizes epigenetic silencing by Polycomb group (PcG) proteins, stimulates enhancer-dependent transcription, and establishes a 'cellular memory' of active transcription of PcG-regulated genes. The mechanisms underlying these TRX functions remain largely unknown, but are presumed to involve its histone H3K4 methyltransferase activity. We report that the SET domains of TRX and TRX-related (TRR) have robust histone H3K4 monomethyltransferase activity in vitro and that Tyr3701 of TRX and Tyr2404 of TRR prevent them from being trimethyltransferases.

Drosophila UTX coordinates with p53 to regulate ku80 expression in response to DNA damage.

UTX is known as a general factor that activates gene transcription during development. Here, we demonstrate an additional essential role of UTX in the DNA damage response, in which it upregulates the expression of ku80 in Drosophila, both in cultured cells and in third instar larvae. We further showed that UTX mediates the expression of ku80 by the demethylation of H3K27me3 at the ku80 promoter upon exposure to ionizing radiation (IR) in a p53-dependent manner.

Polycomb silencing of the Drosophila 4E-BP gene regulates imaginal disc cell growth.

Polycomb group (PcG) proteins are best known for their role in maintaining stable, mitotically heritable silencing of the homeotic (HOX) genes during development. In addition to loss of homeotic gene silencing, some PcG mutants also have small imaginal discs. These include mutations in E(z), Su(z)12, esc and escl, which encode Polycomb repressive complex 2 (PRC2) subunits.

Effects of manganese-toxicity on immune-related organs of cocks.

Manganese (Mn) is a trace element known to be essential for maintaining the proper function and regulation of many biochemical and cellular reactions. However, little is known about the effect of excessive amounts of Mn in immune damage of birds. The aim of this study was to investigate the effect of dietary Mn on immune damage in birds.

Histone demethylase UTX and chromatin remodeler BRM bind directly to CBP and modulate acetylation of histone H3 lysine 27.

Trithorax group (TrxG) proteins antagonize Polycomb silencing and are required for maintenance of transcriptionally active states. We previously showed that the Drosophila melanogaster acetyltransferase CREB-binding protein (CBP) acetylates histone H3 lysine 27 (H3K27ac), thereby directly blocking its trimethylation (H3K27me3) by Polycomb repressive complex 2 (PRC2) in Polycomb target genes. Here, we show that H3K27ac levels also depend on other TrxG proteins, including the histone H3K27-specific demethylase UTX and the chromatin-remodeling ATPase Brahma (BRM).

A barrier-only boundary element delimits the formation of facultative heterochromatin in Drosophila melanogaster and vertebrates.

Formation of facultative heterochromatin at specific genomic loci is fundamentally important in defining cellular properties such as differentiation potential and responsiveness to developmental, physiological, and environmental stimuli. By the nature of their formation, heterochromatin and repressive histone marks propagate until the chain reaction is broken. While certain active promoters can block propagation of heterochromatin, there are also specialized DNA elements, referred to as chromatin barriers, that serve to demarcate the boundary of facultative heterochromatin formation.

Purification of a novel RECQL5-SWI/SNF-RNAPII super complex.

RecQ helicases are members of an evolutionary conserved family of DNA helicases. They are homologous to the RecQ helicase of E. coli, the founding member of the family.

Polycomb Repressive Complex 2 and Trithorax modulate Drosophila longevity and stress resistance.

Polycomb Group (PcG) and Trithorax Group (TrxG) proteins are key epigenetic regulators of global transcription programs. Their antagonistic chromatin-modifying activities modulate the expression of many genes and affect many biological processes. Here we report that heterozygous mutations in two core subunits of Polycomb Repressive Complex 2 (PRC2), the histone H3 lysine 27 (H3K27)-specific methyltransferase E(Z) and its partner, the H3 binding protein ESC, increase longevity and reduce adult levels of trimethylated H3K27 (H3K27me3).

CBP-mediated acetylation of histone H3 lysine 27 antagonizes Drosophila Polycomb silencing.

Trimethylation of histone H3 lysine 27 (H3K27me3) by Polycomb repressive complex 2 (PRC2) is essential for transcriptional silencing of Polycomb target genes, whereas acetylation of H3K27 (H3K27ac) has recently been shown to be associated with many active mammalian genes. The Trithorax protein (TRX), which associates with the histone acetyltransferase CBP, is required for maintenance of transcriptionally active states and antagonizes Polycomb silencing, although the mechanism underlying this antagonism is unknown. Here we show that H3K27 is specifically acetylated by Drosophila CBP and its deacetylation involves RPD3.

Drosophila ESC-like can substitute for ESC and becomes required for Polycomb silencing if ESC is absent.

The Drosophila esc-like gene (escl) encodes a protein very similar to ESC. Like ESC, ESCL binds directly to the E(Z) histone methyltransferase via its WD region. In contrast to ESC, which is present at highest levels during embryogenesis and low levels thereafter, ESCL is continuously present throughout development and in adults.

The N terminus of Drosophila ESC binds directly to histone H3 and is required for E(Z)-dependent trimethylation of H3 lysine 27.

Polycomb group proteins mediate heritable transcriptional silencing and function through multiprotein complexes that methylate and ubiquitinate histones. The 600-kDa E(Z)/ESC complex, also known as Polycomb repressive complex 2 (PRC2), specifically methylates histone H3 lysine 27 (H3 K27) through the intrinsic histone methyltransferase (HMTase) activity of the E(Z) SET domain. By itself, E(Z) exhibits no detectable HMTase activity and requires ESC for methylation of H3 K27.

Global human genetics of HIV-1 infection and China.

Genetic polymorphisms in human genes can influence the risk for HIV-1 infection and disease progression, although the reported effects of these alleles have been inconsistent. This review highlights the recent discoveries on global and Chinese genetic polymorphisms and their association with HIV-1 transmission and disease progression.

The N-terminus of Drosophila ESC mediates its phosphorylation and dimerization.

The ESC protein, like other Polycomb Group proteins, is required for heritable silencing of the homeotic genes. ESC is phosphorylated in vivo, but the region of ESC that is phosphorylated and its consequences are not known. Here, we show that the amino-terminal region of ESC (residues 1-60) mediates its phosphorylation and dimerization.

A 1-megadalton ESC/E(Z) complex from Drosophila that contains polycomblike and RPD3.

Polycomb group (PcG) proteins are required to maintain stable repression of the homeotic genes and others throughout development. The PcG proteins ESC and E(Z) are present in a prominent 600-kDa complex as well as in a number of higher-molecular-mass complexes. Here we identify and characterize a 1-MDa ESC/E(Z) complex that is distinguished from the 600-kDa complex by the presence of the PcG protein Polycomblike (PCL) and the histone deacetylase RPD3.

Polycomb group proteins ESC and E(Z) are present in multiple distinct complexes that undergo dynamic changes during development.

The Polycomb Group proteins are required for stable long-term maintenance of transcriptionally repressed states. Two distinct Polycomb Group complexes have been identified, a 2-MDa PRC1 complex and a 600-kDa complex containing the ESC and E(Z) proteins together with the histone deacetylase RPD3 and the histone-binding protein p55. We report here that there are at least two embryonic ESC/E(Z) complexes that undergo dynamic changes during development and a third larval E(Z) complex that forms after disappearance of ESC.