The TREX complex, which functions in mRNA export, is recruited to mRNA during splicing. Both the splicing machinery and the TREX complex are concentrated in 20–50 discrete foci known as nuclear speckle domains. Using a model system where CMV-DNA constructs were microinjected into HeLa cell nuclei, we have followed the fates of the transcripts. Here we show that transcripts lacking functional splice sites, which are inefficiently exported, do not associate with nuclear speckle domains but are instead distributed throughout the nucleoplasm. In contrast, pre-mRNAs containing functional splice sites accumulate in nuclear speckles, and our data suggest that splicing occurs in these domains. When the TREX components UAP56 or Aly are knocked down, spliced mRNA, as well as total polyA+ RNA, accumulates in nuclear speckle domains. Together, our data raise the possibility that pre-mRNA undergoes splicing in nuclear speckle domains, before release by TREX components for efficient export to the cytoplasm.

The Aurora kinase family comprises three serine/threonine kinases, Aurora-A, -B and -C. Among these, Aurora-A and -B play central roles in mitosis, whereas Aurora-C executes unique roles in meiosis. Overexpression or gene amplification of Aurora kinases have been reported in a broad range of human malignancies, pointing to their role as potent oncogenes in tumorigenesis.Aurora kinases therefore represent promising targets for anticancer therapeutics. So far, a number of Aurora kinase inhibitors (AKIs) have been generated, of which some are currently undergoing clinical trials. Recent studies have unveiled novel unexpected functions of Aurora kinases during cancer development and the mechanisms underlying the anticancer actions of AKIs. In this review, we discuss the most recent advances in Aurora-A kinase research and targeted cancer therapy, focusing on the oncogenic roles and signaling pathways of Aurora-A kinases in contributing tumorigenesis, the recent preclinical and clinical AKI data and potential alternative routes for Aurora-A kinase inhibition.Key words: Aurora-A; Aurora kinase inhibitors (AKIs); targeted cancer therapy; mitosis; tumorigenesis 3 In mammals, the Aurora family of serine/threonine kinases consists of Aurora-A, -B and -C, which share a highly conserved catalytic domain containing auto-phosphorylating sites. The catalytic domain is flanked by a very short C-terminal tail and an N-terminal domain of variable lengths 1,2 . In the C-terminal regions of Auroras, there exists a short amino-acid peptide motif called "destruction box" (D-box). The D-box is recognized by the anaphase-promoting complex/cyclosome (APC/C) for degradation through the ubiquitin/proteasome-dependent pathway ( Fig. 1A). Despite their structural similarities, the expression patterns, cellular localization and physiological functions of these three Aurora kinases are largely distinct.Aurora-A and -B are commonly expressed in most cell types whereas Aurora-C is specially expressed in the testis. Both Aurora-A and -B play key roles in regulating cell-cycle progression from G2 through to cytokinesis. Aurora-C has a unique physiological role in spermatogenesis and functions as a chromosomal passenger protein similar to Aurora-B in mitosis 2 .Overexpression of Aurora-A and -B have been found in multiple types of cancer (Table 1), which function as oncogenes to promote tumorigenesis, providing potential targets for cancer therapy.However, comparatively little information is available regarding the roles of Aurora-C in cancer.In this review, we will focus on recent progress as well as the main unresolved issues associated with Aurora-A in cancer.4 1 FUNCTIONS OF AURORA-A In normal cells a. MitosisIn G1 phase, the level of Aurora-A is rarely detectable. During S phase, a small proportion of Aurora-A is first detected at centrosomes. At late G2 phase, Aurora-A accumulates evidently at centrosomes and becomes activated 3 . During prometaphase and metaphase, active Aurora-A localizes on bipolar spindles and spindle poles after...

Resurrection plants, which are the "gifts" of natural evolution, are ideal models for studying the genetic basis of plant desiccation tolerance. Here, we report a high-quality genome assembly of 301 Mb for the diploid spike moss Selaginella tamariscina, a primitive vascular resurrection plant. We predicated 27 761 protein-coding genes from the assembled S. tamariscina genome, 11.38% (2363) of which showed significant expression changes in response to desiccation. Approximately 60.58% of the S. tamariscina genome was annotated as repetitive DNA, which is an almost 2-fold increase of that in the genome of desiccation-sensitive Selaginella moellendorffii. Genomic and transcriptomic analyses highlight the unique evolution and complex regulations of the desiccation response in S. tamariscina, including species-specific expansion of the oleosin and pentatricopeptide repeat gene families, unique genes and pathways for reactive oxygen species generation and scavenging, and enhanced abscisic acid (ABA) biosynthesis and potentially distinct regulation of ABA signaling and response. Comparative analysis of chloroplast genomes of several Selaginella species revealed a unique structural rearrangement and the complete loss of chloroplast NAD(P)H dehydrogenase (NDH) genes in S. tamariscina, suggesting a link between the absence of the NDH complex and desiccation tolerance. Taken together, our comparative genomic and transcriptomic analyses reveal common and species-specific desiccation tolerance strategies in S. tamariscina, providing significant insights into the desiccation tolerance mechanism and the evolution of resurrection plants.