高通量DNA合成测序化学研究进展

高通量DNA测序是近年来发展起来的革命性技术,大大推动了快速、廉价获取基因组信息的能力,进而对生命科学产生深刻的影响。测序化学是高通量DNA测序的重要内容,且发展十分迅速;一些构思巧妙的新颖测序化学方法被相继报道,本文综述了高通量DNA测序化学的最新研究进展。

DNase1足纹法

本文比较详细介绍了DNaseI足纹法(DNase I-footprinting)的原理、基本操作和注意问题,并对其他酶和化学试剂的足纹法及其可能的应用进行了简要讨论。

Aberrant methylation of the 3q25 tumor suppressor gene PTX3 in human esophageal squamous cell carcinoma

AIM:To identify the novel methylation-silenced gene pentraxin 3(PTX3) in esophageal squamous cell carcinoma(ESCC).METHODS:PTX3 mRNA expression was examined in six human ESCC cell lines,one human immortalized normal esophageal epithelial cell line,primary ESCC tumor tissue,and paired adjacent nontumor tissue using reverse transcription polymerase chain reaction(RTPCR).Semi-quantitative immunohistochemistry was used to examine cellular localisation and protein levels.Methylation specific PCR and bisulphite genomic sequencing were employed to investigate the methylation of the candidate gene.RESULTS:In the majority of ESCC cell lines,we found that PTX3 expression was down-regulated due to gene promoter hypermethylation,which was further confirmed by bisulphite genomic sequencing.Demethylation treatment with 5-aza-2'-deoxycytidine restored PTX3 mRNA expression in ESCC cell lines.Methylation was more common in tumor tissues(85%) than in adjacent nontumor tissues(25%)(P < 0.01).CONCLUSION:PTX3 is down-regulated through promoter hypermethylation in ESCC,and could potentially serve as a biomarker of ESCC.

Critical role of bioinformatics in translating huge amounts of next-generation sequencing data into personalized medicine

Realizing personalized medicine requires integrating diverse data types with bioinformatics.The most vital data are genomic information for individuals that are from advanced next-generation sequencing(NGS) technologies at present.The technologies continue to advance in terms of both decreasing cost and sequencing speed with concomitant increase in the amount and complexity of the data.The prodigious data together with the requisite computational pipelines for data analysis and interpretation are stressors to IT infrastructure and the scientists conducting the work alike.Bioinformatics is increasingly becoming the rate-limiting step with numerous challenges to be overcome for translating NGS data for personalized medicine.We review some key bioinformatics tasks,issues,and challenges in contexts of IT requirements,data quality,analysis tools and pipelines,and validation of biomarkers.

A systematic survey of PRMT interactomes reveals the key roles of arginine methylation in the global control of RNA splicing and translation

Thousands of proteins undergo arginine methylation,a widespread post-translational modification catalyzed by several protein arginine methyltransferases(PRMTs).However,global understanding of their biological functions is limited due to the lack of a complete picture of the catalytic network for each PRMT.Here,we systematically identified interacting proteins for all human PRMTs and demonstrated their functional importance in mRNA splicing and translation.We demonstrated significant overlapping of interactomes of human PRMTs with the known methylarginine-containing proteins.Different PRMTs are functionally redundant with a high degree of overlap in their substrates and high similarities between their putative methylation motifs.Importantly,RNA-binding proteins involved in regulating RNA splicing and translation contain highly enriched arginine methylation regions.Moreover,inhibition of PRMTs globally alternates alternative splicing(AS)and suppresses translation.In particular,ribosomal proteins are extensively modified with methylarginine,and mutations in their methylation sites suppress ribosome assembly,translation,and eventually cell growth.Collectively,our study provides a global view of different PRMT networks and uncovers critical functions of arginine methylation in regulating mRNA splicing and translation.

Improved picoliter-sized micro-reactors for high-throughput biological analysis

High-throughput pyrosequencing,carried out in millions of picoliter-sized reactors on a fiber-optic slide,is known for its longer read length.However,both optical crosstalk(which reduces the signal-to-noise ratio of CCD images)and chemical retention adversely affect the accuracy of chemiluminescence determination,and ultimately decrease the read length and the accuracy of pyrosequencing results.In this study,both titanium and oxidized aluminum films were deposited on the side walls and upper faces of micro-reactor slides to enhance optical isolation;the films reduced the inter-well crosstalk by one order of magnitude.Subsequently,chemical retention was shown to be caused by the lower diffusion coefficient of the side walls of the picolitersized reactors because of surface roughness and random pores.Optically isolated fiber-optic slides over-coated with silicon oxide showed smoother surface morphology,resulting in little chemical retention;this was further confirmed with theoretical calculations.Picoliter-sized micro-reactors coated with titanium-silicon oxide films showed the least inter-well optical crosstalk and chemical retention;these properties are expected to greatly improve the high-throughput pyrosequencing performance.