Comparison of Transformation Efficiency of <italic>piggyBac</italic> Transposon among Three Different Silkworm <italic>Bombyx mori</italic> Strains

Abstract

The transformation rate of three different strains of silkworm Bombyx mori was compared after the introduction of enhanced green fluorescence protein (EGFP)-encoding genes into the silkworm eggs by microinjection of a mixture of piggyBac vector and helper plasmid containing a transposase-encoding sequence. Although there were no significant differences among the three strains in the percentages of fertile moths in microinjected eggs (P=0.1258), the percentages of G(0) transformed moths in fertile moths and injected eggs were both significantly different (P=0.01368 and P=0.02398, respectively). The transformation rate of the Nistari strain (Indian strain) was significantly higher than that of the other two strains, Golden-yellow-cocoon (Vietnamese strain) and Jiaqiu (Chinese strain), which had similar rate. These results indicate that the transformation efficiency of the piggyBac-based system might vary with silkworm strains with different genetic backgrounds. The presence of endogenous piggyBac-like elements might be an important factor influencing the transformation efficiency of introduced piggyBac-derived vectors, and the diverse amount and activation in different silkworm strains might account for the significant differences.

Efficient strategies for changing the diapause character of silkworm eggs and for the germline transformation of diapause silkworm strains

“…For example, the successful germline transformation of silkworm, using a piggyBac transposon‐derived vector, is of particular relevance for new sericulture approaches (Prudhomme & Couble, 2002). Although there have been many reports on the successful germline transformation of silkworm mediated by a piggyBac‐derived vector (Tamura et al , 2000; Tomita et al , 2003; Royer et al , 2005; Dai et al , 2007; Zhong et al , 2007; Zhao et al , 2010), all the studies were conducted using non‐diapausing eggs from polyvoltine silkworm strains, except for the study by Inoue et al (2005), in which diapause strains identified as Nd‐s D were used. The main reason for this discrepancy is that non‐diapausing eggs from polyvoltine strains are capable of continuous development before and after microinjections under normal environment conditions.…”

Analysis of the activity of virus internal ribosome entry site in silkworm <italic>Bombyx mori</italic>

“…Briefly, the microinjection and screening of transgenic silkworms were carried out according to Zhong et al [12]. Eggs of silkworms were collected and microinjected within 8 h after eggs being laid at the syncytial pre-blastoderm stage.…”

The relationship between internal domain sequences of <italic>piggyBac</italic> and its transposition efficiency in BmN cells and <italic>Bombyx mori</italic>

“…BmN cells derived from the ovarian tissue of Bombyx mori were maintained at the Shanghai Institutes for Biological Sciences (Shanghai, China). Microinjection and screening of transgenic silkworms Microinjection and screening of transgenic silkworms were done as described previously [22]. Approximately 15 -20 nl of a 1:0.5 mixture of the transposon (donor) plasmids and transposase (helper) plasmids (total DNA concentration 0.3 mg/ml) were microinjected into each egg.…”