Novel transposase tools for cell-line engineering

ATUM has discovered, characterized, engineered and patented new transposases that work comparable to, or better than previously commercialized transposases. The technology is highly valuable for protein expression and genome engineering applications. It enables a specified sequence to behave as a transposon, a mobile genetic element, which can efficiently transpose between vectors and chromosomes via a “cut & paste” mechanism. The Leap-In Transposase® catalyzes the integration of a transposon containing your gene into TTAT sites in the target genome. During transposition, the Leap-In Transposase recognizes transposon-specific inverted terminal repeat sequences (ITRs) located on both ends of the transposon vector and moves the contents from the original sites and efficiently integrates them into TTAT chromosomal sites. Similar technologies report integration of up to 20 copies of the transposon into unique locations in the genome 72 hours post transfection leading to very high expression levels of payload gene. Furthermore, transposase technologies are highly valuable because of their ability to integrate large payloads. This technology significantly accelerates stable pool and cell-line generation and can be used in conjunction with metabolic selections such as dihydrofolate reductase (DHFR) and glutamine synthetase (GS) or more generic drug selections such as puromycin and neomycin. We have designed transposon based multi-ORF vectors that allow expression of target proteins at controlled ratios. These vectors combined with two orthogonal sets of engineered hyperactive transposases allows multiple levels of genome engineering. The valuable features of the system and performance characterization will be discussed with cell line development and cell engineering case studies

Risk assessment of novel coronavirus COVID-19 outbreaks outside China

We developed a computational tool to assess the risks of novel coronavirus outbreaks outside of China. We estimate the dependence of the risk of a major outbreak in a country from imported cases on key parameters such as: (i) the evolution of the cumulative number of cases in mainland China outside the closed areas; (ii) the connectivity of the destination country with China, including baseline travel frequencies, the effect of travel restrictions, and the efficacy of entry screening at destination; and (iii) the efficacy of control measures in the destination country (expressed by the local reproduction number Rloc ). We found that in countries with low connectivity to China but with relatively high Rloc , the most beneficial control measure to reduce the risk of outbreaks is a further reduction in their importation number either by entry screening or travel restrictions. Countries with high connectivity but low Rloc benefit the most from policies that further reduce Rloc . Countries in the middle should consider a combination of such policies. Risk assessments were illustrated for selected groups of countries from America, Asia, and Europe. We investigated how their risks depend on those parameters, and how the risk is increasing in time as the number of cases in China is growing

The most frequently lost allelic site in human renal cell carcinoma (D3F15S2) on the short arm of chromosome 3 has homologous sequences on rat chromosome 8

It has previously been shown that human chromosome 3 has banding homology to rat chromosome 8. We have previously isolated a cDNA from the D3F15S2 region and designated the gene as RIK. In the present study, we localized the homolog of this gene to rat chromosome 8.Swedish Cancer Society, the Erik Philip-Sörensens Foundation, the Trigger Foundation, The Inga-Britt och Arne Lundbergs Forskningsstiftelse, National Institutes of Health grant 5 R01 CA14054, the CGER-ASLK (Belgium), and the Belgian Ministére de Politique Scientifique (Scinence de la Vie). R.E. received stipends from the Syskonen Svensson Fund, the Robert Lundbergs Minnesfond, and the Swedish Cancer Society. F.B. and S.I. were recipients of fellowships from the Swedish Cancer Society. F.B. was a recipient of a fellowship from the Cancer Research Institute and Cancer Foundation

Consistent chromosome 3p deletion and loss of heterozygosity in renal cell carcinoma

Renal cell carcinoma (RCC) and normal kidney tissues have been examined from 34 patients with sporadic, nonhereditary RCC. Eighteen of the 21 cytogenetically examined tumors (86%) had a detectable anomaly of chromosome arm 3p distal to band 3p11.2-p13, manifested as a deletion, combined with the nonreciprocal translocation of a segment from another chromosome or monosomy 3. Restriction-fragment-length polymorphism analysis showed loss of D1S1 heterozygosity in 16 of the 21 cases (76%). D3S2 heterozygosity was lost in 2 of 11 cases (18%). The variability of the breakpoint between 3p11.2 and 3p13 and the absence of a consistently translocated segment from another chromosome suggests a genetic-loss mechanism, while the activation of a dominant oncogene appears less likely. Together with the previously demonstrated involvement of the 3p14.2 region in a familial case, these findings suggest that RCCs may arise by the deletion of a "recessive cancer gene," as do retinoblastoma and Wilms tumor. The relevant locus must be located on the telomeric side of the D1S1 locus on the short arm of chromosome 3.National Cancer Institute Grant 3ROlCA14054,the Swedish Cancer Society, Deutsche Forschungsgemeinschaft(DFG Ko 841/3-1). G.K. was recipient of a short-term European Molecular Biology Organization Fellowship; R.E., F.B., S.I., and J.S. were recipients of fellowships from the Cancer Research Institute and the Concern Foundation

Differences in c-myc and pvt-1 amplification in sewa sarcoma sublines selected for adherent or non-adherent growth

Conversion of solid sarcomas and carcinomas into ascites tumors depends on the in vivo selection of phenotypically altered tumor cell variants that can grow in the dissociated form. Once selected, they retain this property even after prolonged s.c. growth as solid tumors. From an s.c.-passaged subline of an ascites-converted murine sarcoma (SEWA-AS12), we were able to separate cells adapted to the ascites form of growth from cells that can only grow in the solid form on the basis of their differential adherence to palstic. Both c-myc and pvt-1 were amplified approximately 63- to 77-fold in the non-adherent subline (SEWA-AS12-NA), but only 5- to 8-fold in the adherent subline (SEWA-AS12-ADH). This suggests that c-myc and/or pvt-1 amplification may provide a selective advantage to cells that can grow in the dissociated form.Supported by a USPHS grant from the National Cancer Institute, by The Cancer Research Institute, by the Concern Foundation and by a grant from the Gustav V Jubilaeum Fund. J. Minarovits was a recipient of a fellowship from the Swedish Cancer Society