We report the design and characterization of UNC3866, a potent antagonist of the methyl-lysine (Kme) reading function of the Polycomb CBX and CDY families of chromodomains. Polycomb CBX proteins regulate gene expression by targeting Polycomb Repressive Complex 1 to sites of H3K27me3 via their chromodomains. UNC3866 binds the chromodomains of CBX4 and CBX7 most potently with a Kd of ∼100 nM for each, and is 6- to 18-fold selective versus seven other CBX and CDY chromodomains while being highly selective versus >250 other protein targets. X-ray crystallography revealed that UNC3866 closely mimics the interactions of the methylated H3 tail with these chromodomains. UNC4195, a biotinylated derivative of UNC3866, was used to demonstrate that UNC3866 engages intact PRC1 and that EED incorporation into PRC1 is isoform-dependent in PC3 prostate cancer cells. Finally, UNC3866 inhibits PC3 cell proliferation, a known CBX7 phenotype, while UNC4219, a methylated negative control compound, has negligible effects.

Edited by John M. DenuPRMT5 is the primary enzyme responsible for the deposition of the symmetric dimethylarginine in mammalian cells. In an effort to understand how PRMT5 is regulated, we identified a threonine phosphorylation site within a C-terminal tail motif, which is targeted by the Akt/serum-and glucocorticoid-inducible kinases. While investigating the function of this posttranslational modification, we serendipitously discovered that its free C-terminal tail binds PDZ domains (when unphosphorylated) and 14-3-3 proteins (when phosphorylated). In essence, a phosphorylation event within the last few residues of the C-terminal tail generates a posttranslational modification-dependent PDZ/ 14-3-3 interaction "switch." The C-terminal motif of PRMT5 is required for plasma membrane association, and loss of this switching capacity is not compatible with life. This signaling phenomenon was recently reported for the HPV E6 oncoprotein but has not yet been observed for mammalian proteins. To investigate the prevalence of PDZ/14-3-3 switching in signal transduction, we built a protein domain microarray that harbors PDZ domains and 14-3-3 proteins. We have used this microarray to interrogate the C-terminal tails of a small group of candidate proteins and identified ERBB4, PGHS2, and IRK1 (as well as E6 and PRMT5) as conforming to this signaling mode, suggesting that PDZ/14-3-3 switching may be a broad biological paradigm.Arginine methylation is a common PTM 3 that alters roughly 0.5% of all arginine residues in the cells. There are three types of arginine methylation: monomethylarginine, asymmetric dimethylarginine, and symmetric dimethylarginine (1). PRMT5 is one of nine PRMTs, and it is responsible for the vast majority (Ͼ95%) of the symmetric dimethylarginine modifications (2). PRMT5 was first characterized as a transcriptional repressor for cyclin E1 (3), and in this context, it methylates histone H3R8me2s, H2AR3me2s, and H4R3me2s (4). An epigenetic silencing role for PRMT5 has also recently been reported for the cell cycle inhibitor p21 (5).However, PRMT5 clearly has a number of non-histone substrates that are localized to the cytoplasm and the plasma membrane (6). In the cytoplasm, PRMT5 forms part of the methylosome and methylates a number of splicing factors (7). In keeping with these observations, the conditional deletion of PRMT5 in neural stem cells leads to defects in the core splicing machinery, reduced constitutive splicing, and massive alterations in alternative splicing profiles (8). Thus, this arginine methyltransferase has key biological roles that are associated with each of the major cellular compartments (the nucleus, the cytoplasm, and the plasma membrane), although little is known about how the activity and localization of PRMT5 in these different compartments are regulated.There is an emerging interest in establishing how signal transduction pathways communicate with chromatin and regulate changes to the epigenetic landscapes (9). It is likely that enzymes like PRMT5 may be marked by different ...

Motivation in science learning is believed to be essential for students' pursuit of college-level studies and lifelong interest in science. Yet, the trend of low levels of motivation in learning science continued in college can be linked to a national concern about low scientific literacy levels and science career aspirations. To diagnose the current status of motivation of college students, it is important to have an instrument that can assess students' motivation. The purpose of the present study is to examine the level of motivation of college students and establish the validity and reliability of a motivation questionnaire-the Science Motivation Questionnaire II (SMQ II) developed by Glynn et al. (2011)-using the Rasch-Andrich rating scale model. The original instrument consists of 25 items allocated in five sub-factors. Both person separation reliability and item separation reliability were excellent. The item separation index indicated good variability of the items and the five rating scale functioned well. All Infit and Outfit measures in the Rasch analysis demonstrated a lack of unidimensionality of the science motivation construct in the SMQ II, which supports the deletion of two items to satisfy the unidimensional structure.

Mammalian DNA (cytosine-5) methyltransferase 1 (DNMT1) is essential for maintenance methylation. Phosphorylation of Ser143 (pSer143) stabilizes DNMT1 during DNA replication. Here, we show 14-3-3 is a reader protein of DNMT1pSer143. In mammalian cells 14-3-3 colocalizes and binds DNMT1pSer143 post-DNA replication. The level of DNMT1pSer143 increased with overexpression of 14-3-3 and decreased by its depletion. Binding of 14-3-3 proteins with DNMT1pSer143 resulted in inhibition of DNA methylation activity in vitro. In addition, overexpression of 14-3-3 in NIH3T3 cells led to decrease in DNMT1 specific activity resulting in hypomethylation of the genome that was rescued by transfection of DNMT1. Genes representing cell migration, mobility, proliferation and focal adhesion pathway were hypomethylated and overexpressed. Furthermore, overexpression of 14-3-3 also resulted in enhanced cell invasion. Analysis of TCGA breast cancer patient data showed significant correlation for DNA hypomethylation and reduced patient survival with increased 14-3-3 expressions. Therefore, we suggest that 14-3-3 is a crucial reader of DNMT1pSer143 that regulates DNA methylation and altered gene expression that contributes to cell invasion.

In the version of this article originally published, several lines of text in the last paragraph of the right column on page 1 of the PDF were transposed into the bottom paragraph of the left column. The affected text of the left column should read "The ATP-dependent activities of the BAF (SWI/SNF) chromatin remodeling complexes affect the positioning of nucleosomes on DNA and thereby many cellular processes related to chromatin structure, including transcription, DNA repair and decatenation of chromosomes during mitosis 12,13. " The affected text of the right column should read "SMARCA2/4 BD inhibitors are thus precluded from use for the treatment of SMARCA4 mutant cancers but could provide attractive ligands for PROTAC conjugation. Small molecules binding to other bromodomains have been successfully converted into PROTACs by conjugating them with structures capable of binding to the E3 ligases von Hippel−Lindau (VHL) or cereblon 5,6,10,11,25,26,27. " The errors have been corrected in the PDF version of the paper.