Development of transgenic fish: scientific background.

Nam, Yoon Kwon; Maclean, Norman; Fu, C.; Pandian, T. J.; Eguia, Maria Rowena R.

doi:10.1079/9781845932961.0061

Cited by 14 publications

(14 citation statements)

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“…Therefore, of the 1,800 microinjected embryos, 657 hatched and 453 of these larvae survived until yolk sac absorption was complete. This decreased viability of microinjected embryos has been reported by numerous studies, and the present scores were generally in agreement with those previously reported (Nam et al, 2007). In total, 441 individuals were viable at 1 month post-hatching and 435 individuals survived to 50 days of age, which was not significantly different from the viability of non-injected groups during the same period (P > 0.05).…”

Section: Resultssupporting

confidence: 82%

“…Conversely, the occurrence of PCR-negative fish in the large-sized group could be explained by either a mosaic distribution of the transgene across tissues or an extremely high level of mosaicism in the fin tissues that were chosen for PCR screening. Genetic mosaics are often reported to result from microinjected embryos (Nam et al, 2007).…”

Section: Generation Of Autotransgenic Common Carp and Early Viabilitymentioning

confidence: 99%

“…Manipulation of growth traits through growth hormone (GH)-transgenesis has received a lot of attention as a potential means of overcoming the drawbacks of traditional selective breeding of farmed fishes despite the numerous ecological risks associated with GH-transgenic geno-and phenotypes that remain to be addressed (Devlin et al, 2006;Nam et al, 2007). Early research in fish GH-transgenesis has largely focused on the use of genetic elements of non-piscine origins (i.e., viral or mammalian).…”

Section: Introductionmentioning

confidence: 99%

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Growth Response to a GH-Autotransgenesis in Common Carp Cyprinus carpio

Noh¹,

Kim²

2012

Fisheries and aquatic sciences

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Autotransgenic manipulation with a growth hormone (GH)-construct is a potential approach to improving the growth rates of farmed fish. Here, we present the generation of GH-autotransgenic common carp Cyprinus carpio carrying a transgene comprised of the carp homologous GH gene and a β-actin regulator. Autotransgenic carp showed similar viability to their non-transgenic siblings. Early growth characteristics of founder autotransgenic carp up to 50 days postfertilization were highly variable among individuals; i.e., some fish exhibited significant growth depression, while others showed dramatic acceleration of growth, achieving greater than sixfold increases in body weight relative to their non-transgenic counterparts. Stimulated growth performance became more notable with age and many transgenic individuals of the largest class reached 5 kg within 8 or 9 months, which is at least 10 times heavier than the average body weight of communally grown non-transgenics. Four of six founder transgenic males were successful in passing the transgene to their F 1 offspring with frequencies ranging from 19 to 36%. Growth stimulations were also persistent in all F 1 progeny groups examined.

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Section: Resultssupporting

confidence: 82%

Section: Generation Of Autotransgenic Common Carp and Early Viabilitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Growth Response to a GH-Autotransgenesis in Common Carp Cyprinus carpio

Noh¹,

Kim²

2012

Fisheries and aquatic sciences

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“…Although functional characterization of the 5 0 -flanking upstream regions has been made only in several fish species, it is generally agreed that b-actin promoter has the broad functional potential to drive the constitutive expression of downstream foreign genes in fish cells and tissues (Takagi et al 1994;Noh et al 2003;Hwang et al 2003;Brooks et al 2007;Er-meng et al 2010). The potential utility of the fish b-actin regulator has been successfully demonstrated by previous attempts to generate transgenic fish strains acquiring desired traits such as growth stimulation and disease-resistance (Nam et al 2001(Nam et al , 2007Lin et al 2010), to improve the efficacy of DNA vaccination in fish (Ruiz et al 2008) and also to develop a siRNA-based tool for therapeutic treatment against fish viral diseases (Zenke et al 2010).…”

Section: Introductionmentioning

confidence: 95%

Functional ability of cytoskeletal β-actin regulator to drive constitutive and ubiquitous expression of a fluorescent reporter throughout the life cycle of transgenic marine medaka Oryzias dancena

et al. 2011

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Marine medaka Oryzias dancena, a candidate model organism, represents many attractive merits as a material for experimental transgenesis and/or heterologous expression assay particularly in the field of ecotoxicology and developmental biology. In this study, cytoskeletal β-actin gene was characterized from O. dancena and the functional capability of its promoter to drive constitutive expression of foreign reporter protein was evaluated. The O. dancena β-actin gene possessed a conserved genomic organization of vertebrate major cytoplasmic actin genes and the bioinformatic analysis of its 5'-upstream regulatory region predicted various transcription factor binding motifs. Heterologous expression assay using a red fluorescent protein (RFP) reporter construct driven by the O. dancena β-actin regulator resulted in stunningly bright expression of red fluorescence signals in not only microinjected embryos but also grown-up transgenic adults. Although founder transgenics exhibited mosaic patterns of RFP expression, transgenic offspring in subsequent generations displayed a vivid and uniform expression of RFP continually from embryos to adults. Based on the blot hybridization assays, two transgenic lines established in this study were proven to possess high copy numbers of transgene integrants (approximately 240 and 34 copies, respectively), and the transgenic genotype in both lines could successfully be passed stably up to three generations, although the rate of transgene transmission in one of the two transgenic lines was significantly lower than expected Mendelian ratio. Significant red fluorescence color could be ubiquitously observable in all the tissues or organs of the transgenics. Quantitative real-time RT-PCR represented that the expression pattern of transgene under the regulation of β-actin promoter would resemble, in overall, the regulation of endogenous β-actin gene in adult tissues, although putative mechanism for competitive or independent regulation between transgene and endogenous gene could also be found in several tissues. Results from this study undoubtedly indicate that the O. dancena β-actin promoter would be powerful enough to fluorescently visualize most cell types in vivo throughout its whole lifespan. This study could be a useful start point for a variety of transgenic experiments with this species concerning the constitutive expression of living fluorescent color reporters and other foreign proteins.

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“…In addition, the transgenic manipulation of aquaculture fish species using gene(s) related to quantitative traits has received attention due to its potential as a powerful tool in the molecular genetic breeding of farmed fishes for productivity enhancement (Nam et al, 2001(Nam et al, , 2007. The microinjection of DNA into fertilized eggs has long been utilized to produce transgenic fish strains, although novel methodologies to induce homologous and/or targeted transgenesis have been challenged recently in some fish models (Rembold et al, 2006;Grabher and Wittbrodt, 2007;Casco-Robles et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Concatemer-Associated Transgene Expression Patterns in Transgenic Marine Medaka Oryzias dancena Strains

Cho¹,

Kim²,

Nam

2015

Fisheries and aquatic sciences

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To examine the interrelationship between transgenic insertion patterns and transgene expression profiles in established transgenic fish lines, four stable transgenic marine medaka Oryzias dancena germlines harboring β-actin regulator-driven RFP reporter constructs were selected. The established transgenic strains were characterized with regard to their transgenic genotypes (insertion pattern, concatemer formation, and transgene copy number based on genomic Southern blot hybridization and qPCR assay) and expression characteristics at the mRNA (qRT-PCR), protein (western blot), and phenotypic (fluorescent appearance) levels. From comparative examinations, it was found that transgenic expression at both the transcription and translation levels could be significantly downregulated in transgenic strains, potentially through methylation-mediated transgene silencing that was particularly associated with the formation of a long tail-to-head tandem concatemer in the chromosomal integration site(s). When this occurred, an inverse relationship between the transgene copy number and fluorescence intensity was observed in the resultant transgenic fish. However, with the other transgenic genotype, transgenic individuals with an identical Southern blot hybridization pattern, containing a tandem concatemer(s), had very different expression levels (highly robust vs. low expression strengths), which was possibly related to the differential epigenetic modifications and/or degrees of methylation. The concatemer-dependent downregulation of transgene activity could be induced in transgenic fish, but the overall pattern was strain-specific. Our data suggest that neither a low (or single) transgene copy number nor tandem transgene concatemerization is indicative of strong or silenced transgene expression in transgenic fish carrying a ubiquitous transgene. Hence, a sufficient number of transgenic lineages, with different genotypes, should be considered to ensure the establishment of the best-performance transgenic line(s) for practical applications.

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Development of transgenic fish: scientific background.

Cited by 14 publications

References 0 publications

Growth Response to a GH-Autotransgenesis in Common Carp Cyprinus carpio

Growth Response to a GH-Autotransgenesis in Common Carp Cyprinus carpio

Functional ability of cytoskeletal β-actin regulator to drive constitutive and ubiquitous expression of a fluorescent reporter throughout the life cycle of transgenic marine medaka Oryzias dancena

Concatemer-Associated Transgene Expression Patterns in Transgenic Marine Medaka Oryzias dancena Strains

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