The DEAD-box proteins CYT-19 in Neurospora crassa and Mss116p in Saccharomyces cerevisiae are general RNA chaperones that function in splicing mitochondrial group I and group II introns and in translational activation. Both proteins consist of a conserved ATP-dependent RNA helicase core region linked to N and C-terminal domains, the latter with a basic tail similar to many other DEAD-box proteins. In CYT-19, this basic tail was shown to contribute to non-specific RNA binding that helps tether the core helicase region to structured RNA substrates. Here, multiple sequence alignments and secondary structure predictions indicate that CYT-19 and Mss116p belong to distinct subgroups of DEAD-box proteins, whose C-terminal domains have a defining extended alpha-helical region preceding the basic tail. We find that mutations or C-terminal truncations in the predicted alpha-helical region of Mss116p strongly inhibit RNA-dependent ATPase activity, leading to loss of function in both translational activation and RNA splicing. These findings suggest that the alpha-helical region may stabilize and/or regulate the activity of the RNA helicase core. By contrast, a truncation that removes only the basic tail leaves high RNA-dependent ATPase activity and causes only a modest reduction in translation and RNA splicing efficiency in vivo and in vitro. Biochemical analysis shows that deletion of the basic tail leads to weaker non-specific binding of group I and group II intron RNAs, and surprisingly, also impairs RNA-unwinding at saturating protein concentrations and nucleotide-dependent tight binding of single-stranded RNAs by the RNA helicase core. Together, our results indicate that the two sub-regions of Mss116p's C-terminal domain act in different ways to support and modulate activities of the core helicase region, whose RNA-unwinding activity is critical for both the translation and RNA splicing functions.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2242632 | PMC |
http://dx.doi.org/10.1016/j.jmb.2007.11.041 | DOI Listing |
Nat Commun
January 2025
State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China.
African swine fever virus is highly contagious and causes a fatal infectious disease in pigs, resulting in a significant global impact on pork supply. The African swine fever virus RNA polymerase serves as a crucial multifunctional protein complex responsible for genome transcription and regulation. Therefore, it is essential to investigate its structural and functional characteristics for the prevention and control of African swine fever.
View Article and Find Full Text PDFAcc Chem Res
January 2025
Laboratory for Chemistry and Life Science (CLS), Institute of Integrated Research, Institute of Science Tokyo, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan.
ConspectusThe design of properties and functions of molecular assemblies requires not only a proper choice of building blocks but also control over their packing arrangements. A highly versatile unit in this context is a particular type of triptycene with substituents at the 1,8,13-positions, called tripodal triptycene, which offers predictable molecular packing and multiple functionalization sites, both at the opposite 4,5,16- or 10 (bridgehead)-positions. These triptycene building blocks are capable of two-dimensional (2D) nested hexagonal packing, leading to the formation of 2D sheets, which undergo one-dimensional (1D) stacking into well-defined "2D+1D" structures.
View Article and Find Full Text PDFBiomolecules
December 2024
Division of Biochemistry, University of Fribourg, 1700 Fribourg, Switzerland.
Emerging evidence suggests the serine protease, urokinase plasminogen activator (uPA), may play an important role in the modulation of mood and cognitive functions. Also, preliminary evidence indicates that uPA modulates BDNF activity that is known to be involved in the pathogenesis of mood disorders. However, the physiological functions of uPA in specific brain regions for mediating stress-related emotional behaviors remain to be elucidated.
View Article and Find Full Text PDFInflamm Res
January 2025
Department of Nephrology, the Third Affiliated Hospital of Chongqing Medical University, Chongqing, China.
Background: The pathogenesis of acute kidney injury (AKI) is not fully understood. Tax1-binding protein 1 (TAX1BP1) modulates inflammation and apoptosis through the NF-kB signaling pathway, however, its specific role in ischemic AKI remains unclear.
Methods: We injected a TAX1BP1 overexpression plasmid into the tail vein of male C57BL/6 mice, followed by clamping the bilateral renal arteries to induce AKI.
J Pineal Res
January 2025
Department of Obstetrics and Gynecology, West China Second University Hospital of Sichuan University, Chengdu, Sichuan, China.
Circadian rhythm disruption (CRD), stemming from sleep disorders and/or shift work, is a risk factor for reproductive dysfunction. CRD has been reported to disturb nocturnal melatonin signaling, which plays a crucial role in female reproduction as a circadian regulator and an antioxidant. The hypothalamic-pituitary-ovarian (HPO) axis regulates female reproduction, with luteinizing hormone (LH) pulse pattern playing a pivotal role in folliculogenesis and steroidogenesis.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!