Nuclear scaffold protein p54nrb/NONO facilitates the hypoxia-enhanced progression of hepatocellular carcinoma

Hypoxia and related oxidative stress are closely related to the development and treatment of hepatocellular carcinoma (HCC). However, the mechanism mediated by hypoxia in HCC has not yet been elucidated. Here, we found multifunction scaffold protein p54nrb/NONO exerted pleiotropic effects to regulate hypoxia transcription signals, thereby enhancing the progression of liver cancer. Extensive analysis of clinical data demonstrated that NONO was significantly upregulated and represented as a poor prognostic indicator of HCC. The crucial role of NONO in driving angiogenesis and glycolysis, two well-known cancer phenotypes mediated by hypoxia, was examined in vitro an in vivo. Mechanistically, NONO interacted with and stabilized both HIF-1 and HIF-2 complexes thus activating the transcription of hypoxia-induced genes. Besides, NONO bound pre-mRNA and subsequent mRNA of these genes to facilitate them splicing and mRNA stability, respectively. Thus, NONO knockout seriously disrupted the expression of a cluster of HIF-1/2 targets and impeded hypoxia-enhanced progression in HCC. In conclusion, NONO functioned as a multipurpose scaffold that interacted with HIF-1/2 complex and their downstream transcripts to facilitate the expression of hypoxia-induced genes, allowing malignant proliferation, indicating that NONO might be a potential therapeutic target for HCC.

Androgen and Luteinizing Hormone Stimulate the Function of Rat Immature Leydig Cells Through Different Transcription Signals

The function of immature Leydig cells is regulated by hormones, such as androgen and luteinizing hormone (LH). However, the regulation of this process is still unclear. The objective of this study was to determine whether luteinizing hormone (LH) or androgens contribute to this process. Immature Leydig cells were purified from 35-day-old male Sprague Dawley rats and cultured with LH (1 ng/ml) or androgen (7α-methyl-19- nortestosterone, MENT, 100 nM) for 2 days. LH or MENT treatment significantly increased the androgens produced by immature Leydig cells in rats. Microarray and qPCR and enzymatic tests showed that LH up-regulated the expression of Scarb1, Cyp11a1, Cyp17a1, and Srd5a1 while down-regulated the expression of Sult2a1 and Akr1c14. On the contrary, the expression of Cyp17a1 was up-regulated by MENT. LH and MENT regulate Leydig cell function through different sets of transcription factors. We conclude that LH and androgens participate in the regulation of rat immature Leydig cell function through different transcriptional pathways.

Caudatin Isolated from Cynanchum auriculatum Inhibits Breast Cancer Stem Cell Formation via a GR/YAP Signaling

In the complex tumor microenvironment, cancer stem cells (CSCs), a rare population of cells, are responsible for malignant tumor initiation, metastasis, drug resistance and recurrence. Controlling breast CSCs (BCSCs) using natural compounds is a novel potential therapeutic strategy for clinical cancer treatment. In this study, a mammosphere assay-guided isolation protocol including silica gel, a C18 column, gel filtration, and high-pressure liquid chromatography was used to isolate an inhibitory compound from Cynanchum auriculatum extracts. The isolated inhibitory compound was identified as caudatin. Caudatin inhibited breast cancer cell proliferation, mammosphere formation and tumor growth. Caudatin decreased the CD44+/CD24− and aldehyde dehydrogenase+ cell proportions and the levels of c-Myc, Oct4, Sox2, and CD44. Caudatin induced ubiquitin (Ub)-dependent glucocorticoid receptor (GR) degradation and blocked subsequent Yes-associated protein (YAP) nuclear accumulation and target gene transcription signals in BCSCs. These results show that the GR/YAP signaling pathway regulates BCSC formation and that caudatin may be a potential chemopreventive agent that targets breast cancer cells and CSCs.

Opposing neural signals of CaV1-encoded peptides are tuned by C-terminus mediated inhibition

L-type calcium (CaV1) channels regulate gene expressions via the cascade of excitation-transcription coupling, or directly as standalone CCAT (Calcium Channel Associated Transcriptional-regulator) peptides encoding distal carboxyl-terminus (DCT) of CaV1, both evidenced in dendritogenesis signaling in neurons. We here discover that DCT peptides opposedly mediate these two sets of transcription signals, all tunable in accordance to C-terminus mediated inhibition (CMI) of Ca2+/CaV1 influx. By electrophysiology, neurite morphology, and FRET 2-hybrid binding analyses, we systematically examined native and derived DCT peptides across CaV1, unveiling that the overall balance between cytosolic inhibition versus nuclear facilitation is spatially and temporally tuned by CMI of each DCT variant. Our findings not only resolve several controversies existing to DCT variants, but also propose a de novo scheme of CaV1-centric gene regulation: two concurrent routes of transcription signals initiated from either membrane CaV1 channels or nuclear CaV1-encoded peptides are subject to autonomous feedback tuning by peptide/channel interactions.

REP-elements of the Escherichia coli Genome and Transcription Signals: Positional and Functional Analysis

In the intergenic regions of the Escherichia coli genome there are 356 REP- elements, containing 1-12 repeated sequences with degenerated consensus. Their biological role is poorly understood, but multiplicity in the genome, preferential localization between convergent genes and ability to form hairpin structures have led to the assumption that REP-elements participate in the transcription termination and processes affecting stability of the corresponding RNAs. Though the direct experiments did not confirm the ability of the model REP-sequence to stop RNA synthesis leaving some ambiguity regarding their primary function. In this study, positional and functional analysis was undertaken for the entire set of annotated REP-sequences and the reduced efficiency of RNA synthesis behind the many REP-modules was observed. However, some REP-modules had no effect on the transcription processivity, assuming the inclusion of REP-sequences into RNA and the possibility of their regulatory action. We also observed REP-associated transcription activation and found overlapping promoters. The most unexpected was specific distribution of REP-sequences nearby promoter islands, which indicates their insulator-like action maintaining functional autonomy of the “islands” and assumes functional significance of “island”-born RNAs.

CRISPR-based immune systems of the Sulfolobales: complexity and diversity

CRISPR (cluster of regularly interspaced palindromic repeats)/Cas and CRISPR/Cmr systems of Sulfolobus, targeting DNA and RNA respectively of invading viruses or plasmids are complex and diverse. We address their classification and functional diversity, and the wide sequence diversity of RAMP (repeat-associated mysterious protein)-motif containing proteins encoded in Cmr modules. Factors influencing maintenance of partially impaired CRISPR-based systems are discussed. The capacity for whole CRISPR transcripts to be generated despite the uptake of transcription signals within spacer sequences is considered. Targeting of protospacer regions of invading elements by Cas protein–crRNA (CRISPR RNA) complexes exhibit relatively low sequence stringency, but the integrity of protospacer-associated motifs appears to be important. Different mechanisms for circumventing or inactivating the immune systems are presented.