Bioinformatics analysis of plant orthologous introns: identification of an intronic tRNA-like sequence

tRNA-like structures and their functions

tRNA-like structures (TLSs) were first identified in the RNA genomes of turnip yellow mosaic virus. Since then, TLSs have been found in many other species including mammals, and the RNAs harboring these structures range from viral genomic RNAs to mRNAs and noncoding RNAs. Some progress has also been made on understanding their functions that include regulation of RNA replication, translation enhancement, RNA-protein interaction, and more. In this review, we summarize the current knowledge about the regulations and functions of these TLSs. Possible future directions of the field are also briefly discussed.

PzTAC and PzLAZY from a narrow-crown poplar contribute to regulation of branch angles

Plant architecture, as a basic element influenced by genetic and environmental factors, has an important effect on grain yield via light transmission in agroforestry systems. The molecular mechanism underlying control of branch angle, an important aspect of tree architecture, is not well understood in poplars. Here, we cloned two genes from Populus × zhaiguanheibaiyang (a narrow-crown poplar), designated PzTAC and PzLAZY, which were predicted to be members of the ITG gene family through sequence homology. Transcript levels of the homologous genes were estimated by reverse transcriptase quantitative PCR (RT-qPCR) in different organs of P. × zhaiguanheibaiyang and P. Deltoides 'Zhonglin2025' (a broad-crown poplar). TAC expression was mainly confined to the leaves and annual shoots, whereas LAZY was mainly expressed in the annual shoots and axillary buds. Beside, we detected the promoter expression patterns derived from the PzTAC and PzLAZY genes using the β-glucuronidase (GUS) reporter gene in transgenic Populus × euramericana 'Neva'. GUS activity driven by the PzTAC and PzLAZY promoters was detected in mature leaves, leaf axils and vascular tissues of roots. The PzTAC promoter was mainly active in leaf veins, whereas the PzLAZY promoter was mainly active in mesophyll cells and root tips. The average branch angle in transgenic 35S::PzTAC plants was larger than that of transgenic 35S::PzLAZY plants. The results provide strong evidence that the two genes affect the vascular tissues of transgenic plants to modify branch angles.

PIECE 2.0: an update for the plant gene structure comparison and evolution database

PIECE (Plant Intron Exon Comparison and Evolution) is a web-accessible database that houses intron and exon information of plant genes. PIECE serves as a resource for biologists interested in comparing intron–exon organization and provides valuable insights into the evolution of gene structure in plant genomes. Recently, we updated PIECE to a new version, PIECE 2.0 (http://probes.pw.usda.gov/piece or http://aegilops.wheat.ucdavis.edu/piece). PIECE 2.0 contains annotated genes from 49 sequenced plant species as compared to 25 species in the previous version. In the current version, we also added several new features: (i) a new viewer was developed to show phylogenetic trees displayed along with the structure of individual genes; (ii) genes in the phylogenetic tree can now be also grouped according to KOG (The annotation of Eukaryotic Orthologous Groups) and KO (KEGG Orthology) in addition to Pfam domains; (iii) information on intronless genes are now included in the database; (iv) a statistical summary of global gene structure information for each species and its comparison with other species was added; and (v) an improved GSDraw tool was implemented in the web server to enhance the analysis and display of gene structure. The updated PIECE 2.0 database will be a valuable resource for the plant research community for the study of gene structure and evolution.

JAR3D Webserver: Scoring and aligning RNA loop sequences to known 3D motifs

Many non-coding RNAs have been identified and may function by forming 2D and 3D structures. RNA hairpin and internal loops are often represented as unstructured on secondary structure diagrams, but RNA 3D structures show that most such loops are structured by non-Watson-Crick basepairs and base stacking. Moreover, different RNA sequences can form the same RNA 3D motif. JAR3D finds possible 3D geometries for hairpin and internal loops by matching loop sequences to motif groups from the RNA 3D Motif Atlas, by exact sequence match when possible, and by probabilistic scoring and edit distance for novel sequences. The scoring gauges the ability of the sequences to form the same pattern of interactions observed in 3D structures of the motif. The JAR3D webserver at http://rna.bgsu.edu/jar3d/ takes one or many sequences of a single loop as input, or else one or many sequences of longer RNAs with multiple loops. Each sequence is scored against all current motif groups. The output shows the ten best-matching motif groups. Users can align input sequences to each of the motif groups found by JAR3D. JAR3D will be updated with every release of the RNA 3D Motif Atlas, and so its performance is expected to improve over time.