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Germline mutagenesis mediated by Sleeping Beauty transposon system in mice.

Takeda J, Keng VW, Horie K - Genome Biol. (2007)

Bottom Line: Following the descovery of its transposition activity in mammalian culture systems, the Sleeping Beauty (SB) transposon has since been applied to achieve germline mutagenesis in mice.The SB transposon system has been found to be suitable for comprehensive mutagenesis in mice.Therefore, it is an effective tool as a forward genetics screen for tagged insertional mutagenesis in mice.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Social and Environmental Medicine, Graduate School of Medicine, Osaka University, Yamadaoka, Suita, Osaka 565-0871, Japan. takeda@mr-envi.med.osaka-u.ac.jp

ABSTRACT
Following the descovery of its transposition activity in mammalian culture systems, the Sleeping Beauty (SB) transposon has since been applied to achieve germline mutagenesis in mice. Initially, the transposition efficiency was found to be low in cultured systems, but its activity in germ cells was unexpectedly high. This difference in transposition efficiency was found to be largely dependent on chromosomal status of the host genomic DNA and transposon vector design. The SB transposon system has been found to be suitable for comprehensive mutagenesis in mice. Therefore, it is an effective tool as a forward genetics screen for tagged insertional mutagenesis in mice.

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Related in: MedlinePlus

Possible explanation for why we could not detect GFP signal in double transgenic mice. Green fluorescent protein (GFP) expression at the donor site may be suppressed because of highly methylated transposon DNA (top panel). This suppression may be abrogated during germline transmission. However, the same suppression would be reintroduced at the donor site, probably because of the flanking sequence of the transposon DNA. The suppression may not be reintroduced into the transposed DNA (bottom panel).
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Figure 5: Possible explanation for why we could not detect GFP signal in double transgenic mice. Green fluorescent protein (GFP) expression at the donor site may be suppressed because of highly methylated transposon DNA (top panel). This suppression may be abrogated during germline transmission. However, the same suppression would be reintroduced at the donor site, probably because of the flanking sequence of the transposon DNA. The suppression may not be reintroduced into the transposed DNA (bottom panel).

Mentions: Why could we not detect any GFP expression in the double transgenic mice? The following scheme is postulated to explain this issue (Figure 5). In the double transgenic mice transposon DNA at the original donor sites was highly methylated, and this may explain the suppression of GFP expression at the donor site. DNA methylation is mediated by DNA methyltransferases. Among these, DnmtI methylates CG dinucleotides in a template dependent manner. We speculate that the transposed DNA is also methylated by DnmtI and is continuously suppressed (Figure 5). This suppression may be abrogated during germline transmission, and the same methylation pattern would be reintroduced at the donor site in progeny. However, methylation may not be introduced to the transposed DNA, resulting in GFP expression (Figure 5).


Germline mutagenesis mediated by Sleeping Beauty transposon system in mice.

Takeda J, Keng VW, Horie K - Genome Biol. (2007)

Possible explanation for why we could not detect GFP signal in double transgenic mice. Green fluorescent protein (GFP) expression at the donor site may be suppressed because of highly methylated transposon DNA (top panel). This suppression may be abrogated during germline transmission. However, the same suppression would be reintroduced at the donor site, probably because of the flanking sequence of the transposon DNA. The suppression may not be reintroduced into the transposed DNA (bottom panel).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2106844&req=5

Figure 5: Possible explanation for why we could not detect GFP signal in double transgenic mice. Green fluorescent protein (GFP) expression at the donor site may be suppressed because of highly methylated transposon DNA (top panel). This suppression may be abrogated during germline transmission. However, the same suppression would be reintroduced at the donor site, probably because of the flanking sequence of the transposon DNA. The suppression may not be reintroduced into the transposed DNA (bottom panel).
Mentions: Why could we not detect any GFP expression in the double transgenic mice? The following scheme is postulated to explain this issue (Figure 5). In the double transgenic mice transposon DNA at the original donor sites was highly methylated, and this may explain the suppression of GFP expression at the donor site. DNA methylation is mediated by DNA methyltransferases. Among these, DnmtI methylates CG dinucleotides in a template dependent manner. We speculate that the transposed DNA is also methylated by DnmtI and is continuously suppressed (Figure 5). This suppression may be abrogated during germline transmission, and the same methylation pattern would be reintroduced at the donor site in progeny. However, methylation may not be introduced to the transposed DNA, resulting in GFP expression (Figure 5).

Bottom Line: Following the descovery of its transposition activity in mammalian culture systems, the Sleeping Beauty (SB) transposon has since been applied to achieve germline mutagenesis in mice.The SB transposon system has been found to be suitable for comprehensive mutagenesis in mice.Therefore, it is an effective tool as a forward genetics screen for tagged insertional mutagenesis in mice.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Social and Environmental Medicine, Graduate School of Medicine, Osaka University, Yamadaoka, Suita, Osaka 565-0871, Japan. takeda@mr-envi.med.osaka-u.ac.jp

ABSTRACT
Following the descovery of its transposition activity in mammalian culture systems, the Sleeping Beauty (SB) transposon has since been applied to achieve germline mutagenesis in mice. Initially, the transposition efficiency was found to be low in cultured systems, but its activity in germ cells was unexpectedly high. This difference in transposition efficiency was found to be largely dependent on chromosomal status of the host genomic DNA and transposon vector design. The SB transposon system has been found to be suitable for comprehensive mutagenesis in mice. Therefore, it is an effective tool as a forward genetics screen for tagged insertional mutagenesis in mice.

Show MeSH
Related in: MedlinePlus