N-methyladenosine (mA) messenger RNA methylation is a gene regulatory mechanism affecting cell differentiation and proliferation in development and cancer. To study the roles of mA mRNA methylation in cell proliferation and tumorigenicity, we investigated human endometrial cancer in which a hotspot R298P mutation is present in a key component of the methyltransferase complex (METTL14). We found that about 70% of endometrial tumours exhibit reductions in mA methylation that are probably due to either this METTL14 mutation or reduced expression of METTL3, another component of the methyltransferase complex. These changes lead to increased proliferation and tumorigenicity of endometrial cancer cells, likely through activation of the AKT pathway. Reductions in mA methylation lead to decreased expression of the negative AKT regulator PHLPP2 and increased expression of the positive AKT regulator mTORC2. Together, these results reveal reduced mA mRNA methylation as an oncogenic mechanism in endometrial cancer and identify mA methylation as a regulator of AKT signalling.

Decapentaplegic (Dpp), a Drosophila morphogen signaling protein, transfers directly at synapes made at sites of contact between cells that produce Dpp and cytonemes that extend from recipient cells. The Dpp that cytonemes receive moves together with activated receptors toward the recipient cell body in motile puncta. Genetic loss-of-function conditions for diaphanous, shibire, neuroglian and capricious perturbed cytonemes by reducing their number or only the synapses they make with cells they target; and reduced cytoneme-mediated transport of Dpp and Dpp signaling. These experiments provide direct evidence that cells use cytonemes to exchange signaling proteins, that cytoneme-based exchange is essential for signaling and normal development, and that morphogen distribution and signaling can be contact-dependent, requiring cytoneme synapses.

N6-methyladenosine (m6A) epitranscriptional modification has recently gained much attention. Through the development of m6A sequencing, the molecular mechanism and importance of m6A have been revealed. m6A is the most abundant internal modification in higher eukaryotic mRNAs, which plays crucial roles in mRNA metabolism and multiple biological processes. In this review, we introduce the characteristics of m6A regulators, including “writers” that create m6A mark, “erasers” that show demethylation activity and “readers” that decode m6A modification to govern the fate of modified transcripts. Moreover, we highlight the roles of m6A modification in several common cancers, including solid and non-solid tumors. The regulators of m6A exert enormous functions in cancer development, such as proliferation, migration and invasion. Especially, with the underlying mechanisms being uncovered, m6A and its regulators are expected to be the targets for the diagnosis and treatment of cancers.

Infrared fluorescent proteins (IFPs) provide an additional color to GFP and its red homologs in protein labeling. Based on structural analysis of the dimer interface, a monomeric bateriophytochrome is identified from a sequence database, and is engineered into a naturally-monomeric IFP (mIFP). We demonstrate that mIFP correctly labels proteins in live Drosophila and zebrafish requiring no exogenous cofactor, and will thus be useful in molecular, cell and developmental biology.

Patched (Ptc) is a membrane protein whose function in Hedgehog (Hh) signal transduction has been conserved among metazoans and whose malfunction has been implicated in human cancers. Genetic analysis has shown that Ptc negatively regulates Hh signal transduction, but its activity and structure are not known. We investigated the functional and structural properties of Drosophila Ptc and its C-terminal domain (CTD), 183 residues that are predicted to reside in the cytoplasm. Our results show that Ptc, as well as truncated Ptc deleted of its CTD, forms a stable trimer. This observation is consistent with the proposal that Ptc is structurally similar to trimeric transporters. The CTD itself trimerizes and is required for both Ptc internalization and turnover. Two mutant forms of the CTD, one that disrupts trimerization and the other that mutates the target sequence of the Nedd4 ubiquitin ligase, stabilize Ptc but do not prevent internalization and sequestration of Hh. Ptc deleted of its CTD is stable and localizes to the plasma membrane. These data show that degradation of Ptc is regulated at a step subsequent to endocytosis, although endocytosis is a likely prerequisite. We also show that the CTD of mouse Ptc regulates turnover.[Keywords: Patched; Hedgehog; Hedgehog receptor; protein multimerization; trimer; protein turnover] Supplemental material is available at http://www.genesdev.org.