Zygote-microinjection or in vitro electroporation of isolated zygotes are now widely used methods to produce genome-edited mice. However, these technologies require laborious and time-consuming ex vivo handling of fertilized eggs, including zygote isolation, gene delivery into zygotes and embryo transfer into recipients. We recently developed an alternative method called improved genome-editing via oviductal nucleic acids delivery (i-GONAD), which does not require the above-mentioned ex vivo handing of zygotes, but instead involves intraoviductal instillation of genome-editing components, Cas9 protein and synthetic gRNAs, into the oviducts of pregnant females at the late 1-cell embryo stage under a dissecting microscope and subsequent electroporation. With this method, we succeeded in generating genome-edited mice at relatively high efficiencies (for example, knockout alleles were produced at ~97% efficiency). Here, we extended this improved technology to rats, and found that i-GONAD can create genome-edited rats in various strains, including Sprague Dawley and Lewis, and F1 hybrids (between Sprague Dawley and Brown Norway), with efficiencies of ~62% for indel mutations and ~9% for knock-ins. Thus, i-GONAD will be especially useful for the production of genome-edited rats in small laboratories where expensive micromanipulator systems and highly skilled personnel for embryo manipulation are unavailable.

Nucleus Cytoplasm TGF Smad3 P Smad4 ELIT-1 Positive feedback loop Snail, Vimentin, PAI-1 etc

Although the physiological role of relaxin (RLN) in males remains largely unknown, there is limited evidence that the testis might be a candidate source and target of RLN in boars, as RLN transcripts are detected in the boar testis and it contains RLN-binding sites. To determine whether the boar testis acts as a source and target tissue of RLN, we characterised the expression pattern and cellular localisation of both RLN and its own receptor LGR7 (RXFP1) in boar testes during postnatal development by molecular and immunological approaches. Testes were collected from Duroc boars, and partial cDNA sequences of the boar homologue of human RXFP1 were identified. RLN expression increased through puberty onwards, while RXFP1 expression changed little during development.RLN mRNA and protein expression were restricted to the Leydig cells, whereas both Leydig cells and seminiferous epithelial cells expressed RXFP1 mRNA and protein.Interestingly, RLN was expressed in the testis as an 18 kDa form (the expected size of proRLN), but not as the 6 kDa mature form, during development because of a lack of the enzyme required for proRLN processing. In contrast, RXFP1 was detected at all stages as specific bands of 75 and 91-95 kDa (likely non-glycosylated and glycosylated RXFP1 respectively). Thus, we provide evidence for expression of RLN-RXFP1 ligand-receptor system in the boar testis, suggesting that the testis act as a source and possible target tissue of RLN.

CREBH was identified as a key positive regulator of TGF-β2 transcription in HCV-infected cells. TGF-β2 released from infected cells potentially contributes to cross-induction of TGF-β in an autocrine manner through its own signaling pathway, leading to an increase in fibrogenic responses in adjacent HSCs. (Hepatology 2017;66:1430-1443).

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Background Improved genome-editing via oviductal nucleic acids delivery (i-GONAD) is a new technology that facilitates in situ genome-editing of mammalian zygotes exiting the oviductal lumen. The i-GONAD technology has been developed for use in mice, rats, and hamsters; however, oligonucleotide (ODN)-based knock-in (KI) is more inefficient in rats than mice. To improve the efficiency of i-GONAD in rats we examined KI efficiency using three guide RNAs (gRNA), crRNA1, crRNA2 and crRNA3. These gRNAs recognize different portions of the target locus, but also overlap each other in the target locus. We also examined the effects of commercially available KI -enhancing drugs (including SCR7, L755,507, RS-1, and HDR enhancer) on i-GONAD-mediated KI efficiency. Results The KI efficiency in rat fetuses generated after i-GONAD with crRNA2 and single-stranded ODN was significantly higher (24%) than crRNA1 (5%; p < 0.05) or crRNA3 (0%; p < 0.01). The KI efficiency of i-GONAD with triple gRNAs was 11%. These findings suggest that KI efficiency largely depends on the type of gRNA used. Furthermore, the KI efficiency drugs, SCR7, L755,507 and HDR enhancer, all of which are known to enhance KI efficiency, increased KI efficiency using the i-GONAD with crRNA1 protocol. In contrast, only L755,507 (15 μM) increased KI efficiency using the i-GONAD with crRNA2 protocol. None of them were significantly different. Conclusions We attempted to improve the KI efficiency of i-GONAD in rats. We demonstrated that the choice of gRNA is important for determining KI efficiency and insertion and deletion rates. Some drugs (e.g. SCR7, L755,507 and HDR enhancer) that are known to increase KI efficiency in culture cells were found to be effective in i-GONAD in rats, but their effects were limited.

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Improved genome editing via oviductal nucleic acid delivery (i-GONAD) is a novel method for producing genome-edited mice in the absence of ex vivo handling of zygotes. i-GONAD involves the intraoviductal injection of clustered regularly interspaced short palindromic repeats (CRISPR) ribonucleoproteins via the oviductal wall of pregnant females at 0.7 days post-coitum, followed by in vivo electroporation (EP). Unlike outbred Institute of Cancer Research (ICR) and hybrid mouse strains, genome editing of the most widely used C57BL/6J (B6) strain with i-GONAD has been considered difficult but, recently, setting a constant current of 100 mA upon EP enabled successful i-GONAD in this strain. Unfortunately, the most widely used electroporators employ a constant voltage, and thus we explored conditions allowing the generation of a 100 mA current using two electroporators: NEPA21 (Nepa Gene Co., Ltd.) and GEB15 (BEX Co., Ltd.). When the current and resistance were set to 40 V and 350–400 Ω, respectively, the current was fixed to 100 mA. Another problem in using B6 mice for i-GONAD is the difficulty in obtaining pregnant B6 females consistently because estrous females often fail to be found. A single intraperitoneal injection of low-dose pregnant mare’s serum gonadotrophin (PMSG) led to synchronization of the estrous cycle of these mice. Consequently, approximately 51% of B6 females had plugs upon mating with males 2 days after PMSG administration, which contrasts with the case (≈26%) when B6 females were subjected to natural mating. i-GONAD performed on PMSG-treated pregnant B6 females under conditions of average resistance of 367 Ω and average voltage of 116 mA resulted in the production of pregnant females at a rate of 56% (5/9 mice), from which 23 fetuses were successfully delivered. Nine (39%) of these fetuses exhibited successful genome editing at the target locus.