Two Bombyx Testis-Specific Promoters

The level of sophistication with which one can genetically manipulate insects is very much determined by how well transgene expression can be regulated.

Sterile Insect Technique - Theory

Sterile Insect Technique – Theory

Xu et al (2014) in Insect Molecular Biology describe their successful efforts to isolate promoters from two genes with male Bombyx mori germ-line specific expression patterns.

Generalized view of the reproductive system of male insects.

Generalized view of the reproductive system of male insects.

One gene, β-tubulin, is known to play a role in spermatogenesis and the promoters from various orthologous genes from Drosophila, Aedes and Anopheles have been isolated and used to regulate gene expression in testis. Bombyx mori has four isoforms of β-tubulin with Bmβ4 with the most similarity to Dmβ2 from D. melanogaster. Xu et al. isolated a 1900 bp DNA fragment 5’ of the first ATG of Bmβ4 and tested it for promoter activity.

Bombyx mori with eggs

Bombyx mori with eggs

The second gene, radial spoke head protein (RSHP), encodes a protein which in some non-insects is involved in meiosis, sperm flagellum formation and cilia function, but in insects has an unknown function. In B. mori RSHP1 (BmR1), is expressed specifically in the testis. Xu et al isolated a 1600 bp DNA fragment 5’ of the first ATG of BmR1 and tested it for promoter activity.

Both promoters resulted in very similar patterns of EGFP expression that were limited to the testis beginning during the 5th larval instar and were continuous through the adult stage.

Testis specific expression of GFP using promoters PmR1p and Bmβ4p. from: Xu et al. doi 10.1111/imb.12144

Testis specific expression of GFP using promoters PmR1p and Bmβ4p.
from: Xu et al. doi 10.1111/imb.12144

Germ-line-specific promoters can be useful for a number of applications such as manipulating sex and sex ratios for population control (e.g. Sterile Insect Technique).

If the promoters isolated by Xu et al are similarly functional in other species of Lepidoptera besides B. mori, their utility will be greatly increased and if not then the structure/function relationships elucidated by Xu et al will be useful for cloning the promoters of orthologous genes.

 

Xu J, Bi H, Chen R, Aslam AFM, Li Z, Ling L, Zeng B, Huang Y, Tan A (2014) Transgenic characterization of two testis-specific promoters in the silkworm, Bombyx mori. Insect Mol Biol: n/a-n/a   10.1111/imb.12144

 

 

Facebooktwittergoogle_plusredditpinterestlinkedinmailFacebooktwittergoogle_plusredditpinterestlinkedinmail

Post a Comment

Your email address will not be published. Required fields are marked *