Genomic targeting by recombinase‐mediated cassette exchange in the spotted wing drosophila,Drosophila suzukii

Drosophila suzukii is a significant pest of stone and small fruits. The genome of this species has been sequenced and manipulated by transposon‐mediated transformation and CRISPR/Cas9 gene editing. These technologies open a variety of possibilities for functional genomics and genetic modifications that might improve biologically based population control strategies. Both of these approaches, however, would benefit from genome targeting that would avoid position effects and insertional mutations associated with random transposon vector insertions, and the limited DNA fragment insertion size allowed by gene editing. Here, we describe an efficient recombinase‐mediated cassette exchange (RMCE) system for D. suzukii in which heterospecific lox recombination sites were integrated into the genome by transposon‐mediated transformation and subsequently targeted for double recombination by a donor vector in the presence of Cre recombinase. Three loxN/lox2272 landing site lines have previously been created in D. suzukii, and quantitative PCR determined that polyubiquitin‐regulated enhanced green fluorescent protein expression is least susceptible to position effect suppression in the 443_M26m1 line. We presume that RMCE target sites may also be inserted more specifically into the genome by homology‐directed repair gene editing, thereby avoiding position effects and mutations, while eliminating restrictions on the size of donor constructs for subsequent insertion.     

Intratumoral heterogeneity of esophageal squamous cell carcinoma and its clinical significance

Recent studies have shown that intratumoral heterogeneity is prevalent in esophageal squamous cell cancer (ESCC) based on DNA sequencing and chromosome analysis in multiple regions from the same tumor. This study aimed to investigate the expression of ZNF750, EP300, MTOR and KMT2D and their intratumoral heterogeneity (ITH) in patients with ESCC. A total of 106 cases, who underwent esophagectomy from 2008 to 2010, with two foci from each case, were tested by immunohistochemistry(IHC) as well as 12 cases were tested by RNAscope in this study.We found that 58/106 (54.72%), 66/106 (62.26%), 75/106 (70.75%%) of ESCC showed high expression of ZNF750, EP300, MTOR, respectively by IHC, and 8/12 (66.67%), 10/12 (83.33%), 4/12 (33.33%) and 6/12 (50%) showed high expression of ZNF750, EP300, MTOR and KMT2D, respectively by RNAscope. Multivariate analysis showed that MTOR expression was an independent infavorable prognostic factor of overall survival (OS) (HR?=?1.921; P?=?0.000). This study also found that 44/106(4151%), 37/106 (34.91%), 39/106(36.79%) of ESCC showed heterogeneous expression of ZNF750, EP300 and MTOR respectively by IHC, 8/12(66.67%), 8/12(66.67%), 4/12(33.33%), 4/12(33.33%) of ZNF750, EP300, MTOR and KMT2D respectively by RNAscope, IHC and RNAscope could successfully detect a high prevalence of ITH. In conclusion, findings of this study showed that ZNF750, EP300, MTOR and KMT2D heterogeneously expressed in ESCC. High expression of ZNF750 related to a better outcome, while EP300 and MTOR related to a poor prognosis.     

The Chinese National Twin Registry: a ‘gold mine’ for scientific research

The Chinese National Twin Registry (CNTR) currently includes data from 61 566 twin pair from 11 provinces or cities in China. Of these, 31 705, 15 060 and 13 531 pairs are monozygotic, same‐sex dizygotic and opposite‐sex dizygotic pairs, respectively, determined by opposite sex or intrapair similarity. Since its establishment in 2001, the CNTR has provided an important resource for analysing genetic and environmental influences on chronic diseases especially cardiovascular diseases. Recently, the CNTR has focused on collecting biologic specimens from disease‐concordant or disease‐discordant twin pairs or from twin pairs reared apart. More than 8000 pairs of these twins have been registered, and blood samples have been collected from more than 1500 pairs. In this review, we summarize the main findings from univariate and multivariate genetic effects analyses, gene–environment interaction studies, omics studies exploring DNA methylation and metabolomic markers associated with phenotypes. There remains further scope for CNTR research and data mining. The plan for future development of the CNTR is described. The CNTR welcomes worldwide collaboration.