News & Comment

FOR20, a conserved centrosomal protein, is essential for Plk1 to localize to the centrosome during the S phase and regulate DNA replication. The absence of either Plk1 or FOR20 can stall the cell cycle by a previously unknown intra-S phase centrosomal checkpoint.

Acetylcholine is a cellular mediator selected early in evolution as a key neurotransmitter, but its other biological roles including immune-modulation remain to be elucidated. In a recent paper published in Cell Research, Sun et al. report that acetylcholine modulates cytokine production in macrophages via microRNA-124.

Intestinal bacterial metabolites are an important communication tool between the host immune system and the commensal microbiota to establish mutualism. In a recent paper published in Science, Wendy Garrett and her colleagues report an exciting role of the three most abundant microbial-derived short-chain fatty acids (SCFA), acetic acid, propionic acid and butyric acid, in colonic regulatory T cell (cTreg) homeostasis.

In a recent paper published in Cell, He and colleagues reported the identification and functional characterization of Beclin 2, a mammal-specific homolog of the evolutionarily conserved autophagy-regulatory and oncosuppressive factor Beclin 1. In spite of a non-negligible degree of sequence identity, Beclin 1 and Beclin 2 differ from each other in multiple aspects, including their functional profile as well as the genomic organization of the respective loci.

It has been a long-standing enigma which scramblase causes phosphatidylserine residues to be exposed on the surface of apoptotic cells, thereby facilitating the phagocytic recognition, engulfment and destruction of apoptotic corpses. In a recent paper in Science, Nagata and coworkers reveal that the scramblases Xkr8 and its C. elegans ortholog, CED-8, are activated by caspase cleavage in apoptotic cells.

There exists a worldwide shortage of donor livers for transplant. This may not pose a problem in the future, as Takebe et al. have recently grown functional “liver buds” from stem cells in a dish.

Pluripotency can be experimentally induced from somatic cells by nuclear transfer, fusion with embryonic stem cells, or ectopic transcription factor induction, but attempts to recapitulate this process by chemical means alone have previously failed. In a recent paper published in Science, Hou et al. pursue a rational, albeit laborious approach to identify cocktails of small molecules whose treatment restores pluripotency in adult somatic cells.

The fact that mammals are diploid sets a barrier to rapidly understand the function of non-coding and coding genes in the genome. Recently, Yang et al. reported successful derivation of monkey haploid embryonic stem cells from parthenotes, which provide an effective platform for studying mammalian gene function and enable reverse genetic screening of genes for recessive phenotypes in monkeys.

Fine scale genomic regulation is critical for maintaining genomic integrity and is often disrupted in neurodevelopmental disorders. An intriguing new study reveals the intricate biochemical complexity of de novo post-translational modifications of MeCP2, including activity-dependent protein-protein interactions that 'bridge' the nuclear receptor co-repressor (NCoR) complex to chromatin and lead to alterations in gene expression that characterize Rett syndrome.

A novel coronavirus, the Middle East respiratory syndrome coronavirus, recently emerged through zoonotic transmission, causing a severe lower respiratory tract infection in humans. In two recent papers, one published in Cell Research, the crystal structure of the viral receptor-binding domain in complex with the host CD26/dipeptidyl peptidase 4 receptor has now been characterized.

The tumor-suppressive activity of PTEN has always been attributed to its endogenous intracellular function. Recently two different groups have demonstrated that PTEN is secreted/exported into the extracellular environment for uptake by recipient cells, and functions as a tumor suppressor in a cell non-autonomous manner.

In addition to canonical cis splicing, which joins exons from a single pre-mRNA, various forms of trans splicing have been described, whereby two separate precursor transcripts are linked with each other. A new study by Hu et al. in Cell Research characterizes a novel and unusual splicing variation, called exo-endo trans splicing.

How cells ensure that productive transcription from divergent promoters is limited to the downstream protein-coding region is an important question in the transcription field. A recent study in Nature proposed an answer by revealing that the upstream antisense transcripts undergo early termination through the polyadenylation signal-dependent pathway, and the downstream sense transcripts are protected from premature cleavage by U1 small nuclear ribonucleoprotein (snRNP).

Recently, various studies shed light on the functional significance of enhancer RNAs. Two recent studies published in Nature by Li et al. and Lam et al. highlight the importance of these newly characterized RNA molecules and their key role in controlling transcriptional programs.