Splice and Dice: Intronic microRNAs, Splicing and Cancer

Introns span only a quarter of the human genome, yet they host around 60% of all known microRNAs. Emerging evidence indicates the adaptive advantage of microRNAs residing within introns is attributed to their complex co-regulation with transcription and alternative splicing of their host genes. Intronic microRNAs are often co-expressed with their host genes, thereby providing functional synergism or antagonism that is exploited or decoupled in cancer. Additionally, intronic microRNA biogenesis and the alternative splicing of host transcript are co-regulated and intertwined. The importance of intronic microRNAs is under-recognized in relation to the pathogenesis of cancer.

Spatiotemporal 22q11.21 Protein Network Implicates DGCR8-Dependent MicroRNA Biogenesis as a Risk for Late-Fetal Cortical Development in Psychiatric Diseases

Chromosome 22q11.21 copy number variant (CNV) is a vital risk factor that can be a genetic predisposition to neurodevelopmental disorders (NDD). As 22q11.21 CNV affects multiple genes, causal disease genes and mechanisms affected are still poorly understood. Thus, we aimed to identify the most impactful 22q11.21 CNV genes and the potential impacted human brain regions, developmental stages, and signaling pathways. We constructed the spatiotemporal dynamic networks of 22q11.21 CNV genes using the brain developmental transcriptome and physical protein-protein interactions. The affected brain regions, developmental stages, driver genes, and pathways were subsequently investigated via integrated bioinformatics analysis. As a result, we first identified that 22q11.21 CNV genes affect cortical area mainly during late-fetal periods. Interestingly, we observed that connections between a driver gene DGCR8 and its interacting partners, MECP2 and CUL3, also network hubs, only existed in the network of late-fetal period within cortical region, suggesting their functional specificity during brain development. We also confirmed the physical interaction result between DGCR8 and CUL3 by liquid chromatography-tandem mass spectrometry. As a whole, our results could suggest that the disruption of DGCR8-dependent microRNA biogenesis plays a vital role in NDD for late-fetal cortical development.

Extraribosomal Functions of Cytosolic Ribosomal Proteins in Plants

Ribosomes are basic translational machines in all living cells. The plant cytosolic ribosome is composed of four rRNAs and approximately 81 ribosomal proteins (RPs). In addition to the fundamental functions of RPs in the messenger RNA decoding process as well as in polypeptide synthesis and ribosome assembly, extraribosomal functions of RPs that occur in the absence of the ribosome have been proposed and studied with respect to RPs’ ability to interact with RNAs and non-ribosomal proteins. In a few cases, extraribosomal functions of several RPs have been demonstrated with solid evidences in plants, including microRNA biogenesis, anti-virus defenses, and plant immunity, which have fascinated biologists. We believe that the widespread duplication of RP genes in plants may increase the potential of extraribosomal functions of RPs and more extraribosomal functions of plant RPs will be discovered in the future. In this article we review the current knowledge concerning the extraribosomal functions of RPs in plants and described the prospects for future research in this fascinating area.