Zobrazení zdroje stránky Skippermccullough3897

The implementation of CRISPRi and CRISPRa systems improves our ability to control gene expression in Y. lipolytica and promises to enable more advanced synthetic biology and metabolic engineering studies in this host.CRISPR-Cas9 is frequently used for creating double-strand DNA breaks that result in indels through non-homologous end joining. Indels can revert to wild-type sequence and require sequencing or complex assays to measure. Cutting by two guide RNAs can lead to single indels at either cut site or simultaneous cutting at both sites and repair leading to gene excision.Metabolic engineering frequently requires both gene knockouts and gene integration. CRISPR-Cas9 has been extensively used to create double-stranded DNA breaks that result in indel mutations; however, such mutations can revert or create toxic product. Gene integration can also be accomplished by CRISPR-Cas9 introduced double-stranded DNA breaks and a donor DNA cassette. Here we describe our protocol for combining an efficient gene knockout created by introducing DNA cuts with two guide RNAs with a gene to be integrated at the knockout site. Including guide RNA target sites flanking the homology regions around the gene to be integrated enables both homology-directed repair and homology-mediated end joining, resulting in few deletions and a significant proportion of correctly knocked out and integrated genes.In order to unlock the full potential of Yarrowia lipolytica, as model organism and production host, simple and reliable tools for genome engineering are essential. In this chapter, the practical details of working with the EasyCloneYALI Toolbox are described.Highlights of the EasyCloneYALI Toolbox are high genome editing efficiencies, multiplexed Cas9-mediated knockouts, targeted genomic integrations into characterized intergenic loci, as well as streamlined and convenient cloning for both marker-based and marker-free integrative expression vectors.TALENs (Transcription Activator-Like EndoNuclease) are molecular scissors designed to recognize and introduce a double-strand break at a specific genome locus. They represent tools of interest in the frame of genome edition. Upon cleavage, two different pathways lead to DNA repair Non-homologous End Joining (NHEJ) repair, leading to efficient introduction of short insertion/deletion mutations which can disrupt translational reading frame and Homology Recombination (HR)-directed repair that occurs when exogenous DNA is supplied. Here we introduce how to use TALENs in the oleaginous yeast Yarrowia lipolytica by presenting a step-by-step method allowing to knock out or to introduce in vivo a point mutation in a gene of Yarrowia lipolytica. This chapter describes the material required, the transformation procedure, and the screening process.A mutant excision+/integration- piggyBac transposase can be used to seamlessly excise a chromosomally integrated, piggyBac-compatible selection marker cassette from the Yarrowia lipolytica genome. This piggyBac transposase-based genome engineering process allows for both positive selection of targeted homologous recombination events and scarless or footprint-free genome modifications after precise marker recovery. Residual non-native sequences left in the genome after marker excision can be minimized (0-4 nucleotides) or customized (user-defined except for a TTAA tetranucleotide). Both of these options reduce the risk of unintended homologous recombination events in strains with multiple genomic edits. A suite of dual positive/negative selection marker pairs flanked by piggyBac inverted terminal repeats (ITRs) have been constructed and are available for precise genome engineering in Y. lipolytica using this method. This protocol specifically describes the split marker homologous recombination-based disruption of Y. lipolytica ADE2 with a piggyBac ITR-flanked URA3 cassette, followed by piggyBac transposase-mediated excision of the URA3 marker to leave a 50 nucleotide synthetic barcode at the ADE2 locus. [https://www.selleckchem.com/products/gdc-0077.html Inavolisib] The resulting ade2 strain is auxotrophic for adenine, which enables the use of ADE2 as a selectable marker for further strain engineering.Gonadotropin-releasing hormone agonist (GnRHa) for final oocyte maturation, along with vitrification of all usable embryos followed by transfer in a subsequent frozen-thawed cycle, is the most effective strategy to avoid ovarian hyperstimulation syndrome (OHSS). However, less is known about the ovulation induction triggers effect on early embryo development and blastocyst formation. This study is a secondary analysis of a multicenter, randomized controlled trial, with the aim to compare embryo development in normo-ovulatory women, randomized to GnRHa or human chorionic gonadotropin (hCG) trigger. In all, 4056 retrieved oocytes were observed, 1998 from the GnRHa group (216 women) and 2058 from the hCG group (218 women). A number of retrieved oocytes, mature and fertilized oocytes, and high-quality embryos and blastocysts were similar between the groups. A sub-analysis in 250 women enrolled at the main trial site including 2073 oocytes was conducted to compare embryo morphokinetics and cleavage patterns with EmbryoScope time-lapse system. In total, 1013 oocytes were retrieved from the GnRHa group (124 women) and 1060 oocytes were retrieved from the hCG group (126 women). Morphokinetic parameters and cleavage patterns were comparable between the groups. However, embryos derived from the GnRHa group were less likely to perform rolling during their development than the embryos from the hCG trigger group (OR = 0.41 (95%CI 0.25; 0.67), p-value 0.0003). The comparable results on embryo development and utilization rates between the GnRHa and hCG triggers is of clinical relevance to professionals and infertile patients, when GnRHa trigger and freeze-all is performed to avoid OHSS development. ClinicalTrials.gov Identifier NCT02746562.Emerging literature has shown that women with sleep-disordered breathing (SDB) have increased risk for gestational hypertension/preeclampsia and gestational diabetes. Case reports suggest an association between maternal apnea and fetal heart rate deceleration but data are lacking on how maternal sleep impacts fetal health. Since decelerations may be associated with adverse outcomes, we sought to determine whether fetal heart rate decelerations were associated with SDB. A cohort study of third trimester pregnant women with a singleton fetus was conducted. Participants underwent a home sleep test with continuous portable electronic fetal monitoring. SDB was defined as a respiratory disturbance index (RDI)≥10 events/hour. The temporality between a respiratory event and fetal heart rate decelerations was determined to be present if a deceleration occurred less then 30 s after a respiratory event. Forty women were included with mean (±SD) age, BMI, and gestational age of 32.0±5.5 years, 37.1±8.0 kg/m2, and 34.6±2.