数字PCR技术在核酸标准物质研制中的应用

在标准物质研制领域,生物标准物质的研制逐渐成为了研究热点,同时基于核酸的检测技术的开发与应用又推动了核酸标准物质的进程。核酸标准物质需要高级别、精准的定值方法,数字PCR作为单分子定量技术得到了广泛的应用。数字PCR是一种测定核酸分子的绝对定量方法,如微滴式数字PCR是采用油包水形成的微滴作为反应室,将含有DNA模板的反应溶液分配到大量独立的反应室中进行扩增反应,再通过统计反应室中的阳性信号来定量DNA的拷贝数,从而达到精确定量核酸拷贝数的目的。综述了近年来关于数字PCR及其在核酸标准物质研究领域的最新应用进展,重点综述了其在转基因检测、医疗诊断等领域的应用进展,以期为核酸标准物质的研制提供参考。     

Interaction of Restin with transcription factors

The melanoma-associated antigen (MAGE) genewas first isolated from a melanoma cell in 1987. Up tonow more than 30 members of MAGE have beenidentified. These members build up a super gene fam-ily and were classified into MAGE-A, B, C, D, E, F, Gand H subfamilies by homolog analysis[1]. On the basisof tissue distribution, these antigens could be catego-rized into two groups, CT antigen (Cancer/Testis An-tigen) and non-CT antigen. The MAGE-A, B, C and Ewere considered to be the CT …     

Target enrichment sequencing of 307 germplasm accessions identified ancestry of ancient and modern hybrids and signatures of adaptation and selection in sugarcane (Saccharum spp.), a ‘sweet’ crop with ‘bitter’ genomes

Sugarcane (Saccharum spp.) is a highly energy‐efficient crop primarily for sugar and bio‐ethanol production. Sugarcane genetics and cultivar improvement have been extremely challenging largely due to its complex genomes with high polyploidy levels. In this study, we deeply sequenced the coding regions of 307 sugarcane germplasm accessions. Nearly five million sequence variations were catalogued. The average of 98× sequence depth enabled different allele dosages of sequence variation to be differentiated in this polyploid collection. With selected high‐quality genome‐wide SNPs, we performed population genomic studies and environmental association analysis. Results illustrated that the ancient sugarcane hybrids, S. barberi and S. sinense, and modern sugarcane hybrids are significantly different in terms of genomic compositions, hybridization processes and their potential ancestry contributors. Linkage disequilibrium (LD) analysis showed a large extent of LD in sugarcane, with 962.4 Kbp, 2739.2 Kbp and 3573.6 Kbp for S. spontaneum, S. officinarum and modern S. hybrids respectively. Candidate selective sweep regions and genes were identified during domestication and historical selection processes of sugarcane in addition to genes associated with environmental variables at the original locations of the collection. This research provided an extensive amount of genomic resources for sugarcane community and the in‐depth population genomic analyses shed light on the breeding and evolution history of sugarcane, a highly polyploid species.     

Apoptosis related protein 3, an ATRA-upregulated membrane protein arrests the cell cycle at G1/S phase by decreasing the expression of cyclin D1

Human Apr3 was first cloned from HL-60 cells treated by ATRA. In this study, we further demonstrated that Apr3 could be obviously upregulated by ATRA in many other ATRA sensitive cells, suggesting a common role of Apr3 in ATRA effects. Indirect immunofluorescence assay indicates that Apr3 is a membrane protein, while its truncated form without the predicted transmembrane and intracellular domain, was likely a secreted one. Furthermore, FACS analysis showed that Apr3 overexpression could cause an obvious G1/S phase arrest which might be induced by dramatic reduction of cyclin D1 expression. Strikingly, the truncated Apr3 antagonized the negative role of Apr3 on cell cycle and cyclin D1. Taken together, our data suggest that Apr3 should play an important role in ATRA signal pathway and the predicted transmembrane and/or the intracellular domain mediates Apr3 membrane localization and is vital for the negative regulation on cell cycle and cyclin D1.     

安徽省兽类一属和种新纪录——侯氏猬

Two specimens of Mesechinus hughi were collected from Pingshan, Yi County, Huangshan (29°56'23"N, 117°58'48"E) and Xikou, Xuanzhou, Xuancheng (30°34'42"N, 118°41'47"E) in Anhui Province, in July and September 2018, respectively. Ears of the two specimens are similar, in length, to the surrounding spines. The two specimens have few wholly white spines, and most spines (>95%) have four sections; white constituting the basal two-thirds, followed by a black ring, narrow light ring, and black tip. These characters are similar to those of the specimens from the type locality (Baoji, Shaanxi Province). The P-distance of Cyt b between the population in Anhui and that of Shaanxi is from 4.9% to 5.3%, and maximum likelihood phylogenetic analyses support the two populations as monophyletic (BS = 95%). This was the first recorded distribution of Mesechinus in Anhui Province and Mesechinus hughi south of the Changjiang River.     

The sense strand pre-cleaved RNA duplex mediates an efficient RNA interference with less off-target and immune response effects

RNA interference is an appealing and promising therapeutic approach in cancer and other diseases. Designing novel strategies aiming to increase the efficiency, duration, and reduce the off-target silencing by sense strand is of great significance for its future application clinically. Here, we report that RNA duplex with the sense strand pre-cleaved at the base between base 10 and 11 relative to the 5′ end of the antisense strand induced a target-specific RNA silencing effectively. Furthermore, different from the canonical RNA duplex, this novel RNA duplex rarely inhibits the luciferase activity in the reporter, bearing the target sequence corresponding to the sense strand, suggesting a less off-target effects of this novel strategy. Furthermore, the immune response of the novel RNA duplex induced a much milder immune response as seen from the NFkappaB activity. In addition, our newly designed RNA duplex should be easier for preservation than the asymmetric RNA duplex. Our results establish a novel method to design a new class of RNA duplex for improved RNA interference.     

Gastrointestinal tract specific gene GDDR inhibits the progression of gastric cancer in a TFF1 dependent manner

The novel gene GDDR, also named trefoil factor interactions 1, is abundantly expressed in human gastric epithelial cells but significantly down-regulated in gastric cancer. In this study, we first demonstrated that GDDR was specifically expressed in the gastrointestinal tract epithelium, while suppressed in gastric cancer cells. Forced expression of GDDR suppressed the tumor growth as shown by MTT and xenograft assay. siRNA mediated TFF1 inhibition nearly blocked the growth inhibitory role of GDDR. In summary, our study suggested that gastrointestinal tract specific gene GDDR might inhibit gastric cancer growth in a TFF1 dependent manner.