Cbx4 is a polycomb group protein that is also a SUMO E3 ligase, but its potential roles in tumorigenesis remain to be explored. Here, we report that Cbx4, but not other members of the Cbx family, enhances hypoxia-induced vascular endothelial growth factor (VEGF) expression and angiogenesis in hepatocellular carcinoma (HCC) cells through enhancing HIF-1α sumoylations at K391 and K477 in its two SUMO-interacting motifs-dependent mechanisms and increasing transcriptional activity of HIF-1. The Cbx4 expression is significantly correlated with VEGF expression, angiogenesis, and the overall survival of HCC patients and also in subcutaneously and orthotopically transplanted mice HCC models. Collectively, our findings demonstrate that Cbx4 plays a critical role in tumor angiogenesis by governing HIF-1α protein.
BackgroundThe genetic relationships reported by recent studies between Sherpas and Tibetans are controversial. To gain insights into the population history and the genetic basis of high-altitude adaptation of the two groups, we analyzed genome-wide data in 111 Sherpas (Tibet and Nepal) and 177 Tibetans (Tibet and Qinghai), together with available data from present-day human populations.ResultsSherpas and Tibetans show considerable genetic differences and can be distinguished as two distinct groups, even though the divergence between them (~3200–11,300 years ago) is much later than that between Han Chinese and either of the two groups (~6200–16,000 years ago). Sub-population structures exist in both Sherpas and Tibetans, corresponding to geographical or linguistic groups. Differentiation of genetic variants between Sherpas and Tibetans associated with adaptation to either high-altitude or ultraviolet radiation were identified and validated by genotyping additional Sherpa and Tibetan samples.ConclusionsOur analyses indicate that both Sherpas and Tibetans are admixed populations, but the findings do not support the previous hypothesis that Tibetans derive their ancestry from Sherpas and Han Chinese. Compared to Tibetans, Sherpas show higher levels of South Asian ancestry, while Tibetans show higher levels of East Asian and Central Asian/Siberian ancestry. We propose a new model to elucidate the differentiated demographic histories and local adaptations of Sherpas and Tibetans.Electronic supplementary materialThe online version of this article (doi:10.1186/s13059-017-1242-y) contains supplementary material, which is available to authorized users.
Zebrafish have been found to be a premier model organism in biological and regeneration research. However, the comprehensive cell compositions and molecular dynamics during tissue regeneration in zebrafish remain poorly understood. Here, we utilized Microwell-seq to analyze more than 250,000 single cells covering major zebrafish cell types and constructed a systematic zebrafish cell landscape. We revealed single-cell compositions for 18 zebrafish tissue types covering both embryo and adult stages. Single-cell mapping of caudal fin regeneration revealed a unique characteristic of blastema population and key genetic regulation involved in zebrafish tissue repair. Overall, our single-cell datasets demonstrate the utility of zebrafish cell landscape resources in various fields of biological research.
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