A cadherin-like protein functions as a receptor for Bacillus thuringiensis Cry1Aa and Cry1Ac toxins on midgut epithelial cells of Bombyx mori larvae.
Aminopeptidase N (APN) and cadherin-like protein (BtR175) from Bombyx mori larvae were examined for their roles in Cry1Aa- and Cry1Ac-induced lysis of B. mori midgut epithelial cells (MECs). APNs and BtR175 were present in all areas of the midgut, were particularly abundant in the posterior region, and were found only on columnar cell microvilli and not on the lateral membrane that makes cell-cell contacts. This distribution was in accordance with the distribution of Cry1A-susceptible MECs in the midgut. The lytic activity of Cry1Aa and Cry1Ac on collagenase-dissociated MECs was linearly dependent on toxin concentration. Although pre-treatment of MECs with anti-BtR175 antibody was observed to partially inhibit the lytic activity exerted by 0.1-1 nM Cry1Aa toxin or 5 nM Cry1Ac toxin, no significant inhibition was observed when MECs were pre-treated with anti-APN antibody. These results suggest that BtR175 functions as a major receptor for Cry1A toxins in the midgut of B. mori larvae.
Hara
Hirotaka
H
Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan.
Atsumi
Shogo
S
Yaoi
Katsuro
K
Nakanishi
Kazuko
K
Higurashi
Satoshi
S
Miura
Nami
N
Tabunoki
Hiroko
H
Sato
Ryoichi
R
D000818:Animals; D001413:Bacillus thuringiensis / Q000378:metabolism*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000378:metabolism*; D001427:Bacterial Toxins; D001483:Base Sequence; D012831:Bombyx / Q000254:growth & development / Q000378:metabolism*; D015820:Cadherins / Q000378:metabolism*; D017931:DNA Primers; D004731:Endotoxins / Q000378:metabolism*; D004847:Epithelial Cells / Q000378:metabolism; D006460:Hemolysin Proteins; D019476:Insect Proteins; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D007814:Larva / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism*
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D015820:Cadherins; C095416:Cry toxin receptors; D017931:DNA Primers; D004731:Endotoxins; D006460:Hemolysin Proteins; D019476:Insect Proteins; D011956:Receptors, Cell Surface; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D007770:L-Lactate Dehydrogenase