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Conditional embryonic lethality to improve the sterile insect technique in Ceratitis capitata (Diptera: Tephritidae).

Schetelig MF, Caceres C, Zacharopoulou A, Franz G, Wimmer EA - BMC Biol. (2009)

Bottom Line: These elements act differently in expression strength and their ability to drive lethal effector gene activation.Moreover, position effects strongly influence the efficiency of the system.Out of 60 combinations of driver and effector construct integrations, several lines resulted in larval and pupal lethality with one line showing complete embryonic lethality.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Developmental Biology, Göttingen Center for Molecular Biosciences, Johann-Friedrich-Blumenbach-Institute of Zoology and Anthropology, Georg-August-University Göttingen, GZMB, Ernst-Caspari-Haus, Göttingen, Germany. marc.schetelig@ars.usda.gov

ABSTRACT

Background: The sterile insect technique (SIT) is an environment-friendly method used in area-wide pest management of the Mediterranean fruit fly Ceratitis capitata (Wiedemann; Diptera: Tephritidae). Ionizing radiation used to generate reproductive sterility in the mass-reared populations before release leads to reduction of competitiveness.

Results: Here, we present a first alternative reproductive sterility system for medfly based on transgenic embryonic lethality. This system is dependent on newly isolated medfly promoter/enhancer elements of cellularization-specifically-expressed genes. These elements act differently in expression strength and their ability to drive lethal effector gene activation. Moreover, position effects strongly influence the efficiency of the system. Out of 60 combinations of driver and effector construct integrations, several lines resulted in larval and pupal lethality with one line showing complete embryonic lethality. This line was highly competitive to wildtype medfly in laboratory and field cage tests.

Conclusion: The high competitiveness of the transgenic lines and the achieved 100% embryonic lethality causing reproductive sterility without the need of irradiation can improve the efficacy of operational medfly SIT programs.

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Medfly genes expressed specifically during cellularization. Gene expression is shown by WMISH on embryos from a 0–48 h egg collection of wildtype (WT) medflies with gene-specific RNA probes for different stages during embryogenesis: early blastoderm (×1), cellularization (×2), germ band elongation (×3) and germ band retraction (×4). The genes C.c.-slam (Ay), C.c.-sub2_99 (By), C.c.-CG2186 (Cy), C.c.-sry α (Dy), C.c.-sub2_63 (Ey), and C.c.-sub2_65 (Fy) are strongly expressed during cellularization (×2). C.c.-sub2_63 also showed expression during germ band elongation (E3). Gene names used in Schetelig et al. (2007) [9] correspond as follows: sub1_68 = sub1_24 = C.c.-slam; sub1_478 = C.c.-CG2186.
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Figure 1: Medfly genes expressed specifically during cellularization. Gene expression is shown by WMISH on embryos from a 0–48 h egg collection of wildtype (WT) medflies with gene-specific RNA probes for different stages during embryogenesis: early blastoderm (×1), cellularization (×2), germ band elongation (×3) and germ band retraction (×4). The genes C.c.-slam (Ay), C.c.-sub2_99 (By), C.c.-CG2186 (Cy), C.c.-sry α (Dy), C.c.-sub2_63 (Ey), and C.c.-sub2_65 (Fy) are strongly expressed during cellularization (×2). C.c.-sub2_63 also showed expression during germ band elongation (E3). Gene names used in Schetelig et al. (2007) [9] correspond as follows: sub1_68 = sub1_24 = C.c.-slam; sub1_478 = C.c.-CG2186.

Mentions: The isolation of the medfly homologs of the cellularization genes sry α and o by degenerate primer PCR using an embryonic cDNA pool was not successful [9]. Thus, we carried out PCR-based cDNA subtractions of different embryonic stages and identified several cellularization-specifically-expressed genes (Figure 1). The genes C.c.-slow as molasses (C.c.-slam; Figure 1A), C.c.-sub2_99 (Figure 1B), C.c.-CG2186 (Figure 1C), C.c.-serendipity α (C.c.-sry α; Figure 1D), C.c.-sub2_63 (Figure 1E), and C.c.-sub2_65 (Figure 1F) are expressed specifically during medfly blastoderm cellularization (Figure 1). None of the genes shows maternal expression or expression at later stages, except C.c.-sub2_63, which is additionally expressed during germ band elongation (Figure 1E3).


Conditional embryonic lethality to improve the sterile insect technique in Ceratitis capitata (Diptera: Tephritidae).

Schetelig MF, Caceres C, Zacharopoulou A, Franz G, Wimmer EA - BMC Biol. (2009)

Medfly genes expressed specifically during cellularization. Gene expression is shown by WMISH on embryos from a 0–48 h egg collection of wildtype (WT) medflies with gene-specific RNA probes for different stages during embryogenesis: early blastoderm (×1), cellularization (×2), germ band elongation (×3) and germ band retraction (×4). The genes C.c.-slam (Ay), C.c.-sub2_99 (By), C.c.-CG2186 (Cy), C.c.-sry α (Dy), C.c.-sub2_63 (Ey), and C.c.-sub2_65 (Fy) are strongly expressed during cellularization (×2). C.c.-sub2_63 also showed expression during germ band elongation (E3). Gene names used in Schetelig et al. (2007) [9] correspond as follows: sub1_68 = sub1_24 = C.c.-slam; sub1_478 = C.c.-CG2186.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2662800&req=5

Figure 1: Medfly genes expressed specifically during cellularization. Gene expression is shown by WMISH on embryos from a 0–48 h egg collection of wildtype (WT) medflies with gene-specific RNA probes for different stages during embryogenesis: early blastoderm (×1), cellularization (×2), germ band elongation (×3) and germ band retraction (×4). The genes C.c.-slam (Ay), C.c.-sub2_99 (By), C.c.-CG2186 (Cy), C.c.-sry α (Dy), C.c.-sub2_63 (Ey), and C.c.-sub2_65 (Fy) are strongly expressed during cellularization (×2). C.c.-sub2_63 also showed expression during germ band elongation (E3). Gene names used in Schetelig et al. (2007) [9] correspond as follows: sub1_68 = sub1_24 = C.c.-slam; sub1_478 = C.c.-CG2186.
Mentions: The isolation of the medfly homologs of the cellularization genes sry α and o by degenerate primer PCR using an embryonic cDNA pool was not successful [9]. Thus, we carried out PCR-based cDNA subtractions of different embryonic stages and identified several cellularization-specifically-expressed genes (Figure 1). The genes C.c.-slow as molasses (C.c.-slam; Figure 1A), C.c.-sub2_99 (Figure 1B), C.c.-CG2186 (Figure 1C), C.c.-serendipity α (C.c.-sry α; Figure 1D), C.c.-sub2_63 (Figure 1E), and C.c.-sub2_65 (Figure 1F) are expressed specifically during medfly blastoderm cellularization (Figure 1). None of the genes shows maternal expression or expression at later stages, except C.c.-sub2_63, which is additionally expressed during germ band elongation (Figure 1E3).

Bottom Line: These elements act differently in expression strength and their ability to drive lethal effector gene activation.Moreover, position effects strongly influence the efficiency of the system.Out of 60 combinations of driver and effector construct integrations, several lines resulted in larval and pupal lethality with one line showing complete embryonic lethality.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Developmental Biology, Göttingen Center for Molecular Biosciences, Johann-Friedrich-Blumenbach-Institute of Zoology and Anthropology, Georg-August-University Göttingen, GZMB, Ernst-Caspari-Haus, Göttingen, Germany. marc.schetelig@ars.usda.gov

ABSTRACT

Background: The sterile insect technique (SIT) is an environment-friendly method used in area-wide pest management of the Mediterranean fruit fly Ceratitis capitata (Wiedemann; Diptera: Tephritidae). Ionizing radiation used to generate reproductive sterility in the mass-reared populations before release leads to reduction of competitiveness.

Results: Here, we present a first alternative reproductive sterility system for medfly based on transgenic embryonic lethality. This system is dependent on newly isolated medfly promoter/enhancer elements of cellularization-specifically-expressed genes. These elements act differently in expression strength and their ability to drive lethal effector gene activation. Moreover, position effects strongly influence the efficiency of the system. Out of 60 combinations of driver and effector construct integrations, several lines resulted in larval and pupal lethality with one line showing complete embryonic lethality. This line was highly competitive to wildtype medfly in laboratory and field cage tests.

Conclusion: The high competitiveness of the transgenic lines and the achieved 100% embryonic lethality causing reproductive sterility without the need of irradiation can improve the efficacy of operational medfly SIT programs.

Show MeSH
Related in: MedlinePlus