Project description:Dopaminergic (DA) neurons marked by the dopamine transporter (DAT) have multiple physiological functions and are involved in the regulation of mental and neurological diseases, prompting in-depth studies into their development and functions. This research explores the spatiotemporal proteomic and transcriptomic changes in DAT+ DA neurons within key brain regions involved in DA signaling—the nucleus accumbens (NAc), substantia nigra (SNc), and ventral tegmental area (VTA). Utilizing cutting-edge multi-omics techniques, such as ultrasensitive trace sample proteomics and SMART_x0002_seq2 for transcriptomics, we examine the DA neuronal system at critical postnatal milestones: postnatal day 7 (P7), postnatal day 30 (P30), and postnatal day 60 (P60). The study reveals unique molecular profiles within DA neuron populations, showcasing their varied functional roles and developmental progression. Immunofluorescence mapping illustrates these molecular distributions, validating the quantitative data and highlighting the dynamic molecular structure of DA neurons. Our findings notably highlight a marked increase over time in Aldh1a1 expression, an essential enzyme for retinoic acid production, suggesting its evolving role in neuronal development and specific functions. This comprehensive analysis offers a profound molecular perspective on DAT+ DA neuron development, enhancing our understanding of their functional diversity and potential relevance in DA-related diseases.
Project description:Abstract - 18S nonfunctional rRNA decay (NRD) detects and eliminates translationally nonfunctional 18S rRNA. While this process is critical for ribosome quality control, the mechanisms underlying nonfunctional 18S rRNA turnover remain elusive, particularly in mammals. Here, we show that mammalian 18S NRD initiates through the integrated stress response (ISR) via GCN2. Nonfunctional 18S rRNA induces translational arrest at start sites. Biochemical analyses demonstrate that ISR activation limits translation initiation and attenuates collisions between scanning 43S preinitiation complexes and stalled nonfunctional ribosomes. The ISR promotes 18S NRD and 40S ribosomal protein turnover by RNF10-mediated ubiquitination. Ultimately, RIOK3 binds the resulting ubiquitinated 40S subunits and facilitates 18S rRNA decay. Overall, mammalian 18S NRD acts through GCN2, followed by ubiquitin-dependent 18S rRNA degradation involving the ubiquitin E3 ligase RNF10 and the atypical protein kinase RIOK3. These findings establish a dynamic feedback mechanism by which the GCN2-RNF10-RIOK3 axis surveils ribosome functionality at the translation initiation step.
Project description:Because of severe abiotic limitations, Antarctic soils represent simplified ecosystems, where microorganisms are the principle drivers of nutrient cycling. This relative simplicity makes these ecosystems particularly vulnerable to perturbations, like global warming, and the Antarctic Peninsula is among the most rapidly warming regions on the planet. However, the consequences of the ongoing warming of Antarctica on microorganisms and the processes they mediate are unknown. Here, using 16S rRNA gene pyrosequencing and qPCR, we report a number of highly consistent changes in microbial community structure and abundance across very disparate sub-Antarctic and Antarctic environments following three years of experimental field warming (+ 0.5-2°C). Specifically, we found significant increases in the abundance of fungi and bacteria and in the Alphaproteobacteria-to-Acidobacteria ratio. These alterations were linked to a significant increase in soil respiration. Furthermore, the shifts toward generalist or opportunistic bacterial communities following warming weakened the linkage between bacterial diversity and functional diversity. Warming also increased the abundance of some organisms related to the N-cycle, detected as an increase in the relative abundance of nitrogenase genes via GeoChip microarray analyses. Our results demonstrate that soil microorganisms across a range of sub-Antarctic and Antarctic environments can respond consistently and rapidly to increasing temperatures, thereby potentially disrupting soil functioning.