Spliceosomal introns play a key role in eukaryotic genome evolution and protein diversity. A large Rab GTPase family has been identified in a unicellular eukaryote Trichomonas vaginalis. However, the characteristics of introns in Rab genes of T. vaginalis have not been investigated previously. In this study, we identified a 25-bp spliceosomal intron in the T. vaginalis Rab1a (TvRab1a) gene, the smallest intron in T. vaginalis to be characterized to date. This intron contains a canonical splice site at both 5' (GT) and 3' (AG) ends, and a putative branch-point sequence (TCTAAC) that matches the Trichomonad consensus sequence of ACTAAC except for the first nucleotide. The position and phase of the TvRab1a intron are evolutionarily conserved in Rab1 homologous genes across at least five eukaryotic supergroups, including Opisthokonta, Amoebozoa, Excavata, Chromalveolata, and Plantae. These results strongly suggest that the TvRab1a intron is likely to be an ancient spliceosomal intron, and it can therefore be used as a phylogenetic marker to evaluate particular eukaryotic groupings. Identification and characterization of the TvRabla intron may provide an insight into the evolution of the large Rab repertoire in T. vaginalis.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/j.biocel.2008.09.014 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Structures of aberrant spliceosome intermediates on their way to disassembly.
Nat Struct Mol Biol
January 2025
Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany.
Intron removal during pre-mRNA splicing is of extraordinary complexity and its disruption causes a vast number of genetic diseases in humans. While key steps of the canonical spliceosome cycle have been revealed by combined structure-function analyses, structural information on an aberrant spliceosome committed to premature disassembly is not available. Here, we report two cryo-electron microscopy structures of post-B spliceosome intermediates from Schizosaccharomyces pombe primed for disassembly.
View Article and Find Full Text PDFDDX1 is required for non-spliceosomal splicing of tRNAs but not of XBP1 mRNA.
Commun Biol
January 2025
Stem Cell Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo, 156-8506, Japan.
RNA helicase DEAD-box helicase 1 (DDX1) forms a complex with the RNA ligase 2´,3´-cyclic phosphate and 5´-OH ligase (RTCB), which plays a vital role in non-spliceosomal splicing of tRNA and X-box binding protein 1 (XBP1) mRNA. However, the importance of DDX1 in non-spliceosomal splicing has not been clarified. To analyze the functions of DDX1 in mammalian cells, we generated DDX1 cKO cells from the polyploid human U2OS cell line and found that splicing of intron-containing tRNAs was significantly disturbed in DDX1-deficient cells, whereas endoplasmic reticulum (ER) stress-induced splicing of XBP1 mRNA was unaffected.
View Article and Find Full Text PDFStructural basis of 5' splice site recognition by the minor spliceosome.
Mol Cell
January 2025
European Molecular Biology Laboratory (EMBL), EMBL Grenoble, 71 Avenue des Martyrs, 38042 Grenoble, France. Electronic address:
The minor spliceosome catalyzes excision of U12-dependent introns from precursors of eukaryotic messenger RNAs (pre-mRNAs). This process is critical for many cellular functions, but the underlying molecular mechanisms remain elusive. Here, we report a cryoelectron microscopy (cryo-EM) reconstruction of the 13-subunit human U11 small nuclear ribonucleoprotein particle (snRNP) complex in apo and substrate-bound forms, revealing the architecture of the U11 small nuclear RNA (snRNA), five minor spliceosome-specific factors, and the mechanism of the U12-type 5' splice site (5'SS) recognition.
View Article and Find Full Text PDFHigher Intron Retention Levels in Female Alzheimer's Brains May Be Linked to Disease Prevalence.
Aging Cell
January 2025
Temasek Life Sciences Laboratory, Singapore, Singapore.
Multimodal study of Alzheimer's disease (AD) dorsolateral prefrontal cortex (DLPFC) showed AD-related aberrant intron retention (IR) and proteomic changes not observed at the RNA level. However, the role of sex and how IR may impact the proteome are unclear. Analysis of DLPFC transcriptome showed a clear sex-biased pattern where female AD had 1645 elevated IR events compared to 80 in male AD DLPFC.
View Article and Find Full Text PDFTranscriptome-wide outlier approach identifies individuals with minor spliceopathies.
medRxiv
January 2025
Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA.
RNA-sequencing has improved the diagnostic yield of individuals with rare diseases. Current analyses predominantly focus on identifying outliers in single genes that can be attributed to cis-acting variants within the gene locus. This approach overlooks causal variants with trans-acting effects on splicing transcriptome-wide, such as variants impacting spliceosome function.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!