Characterization and identification of the integrin family in silkworm, Bombyx mori

• The whole silkworm integrin family was first cloned and sequenced.
• 6 integrins present in various tissues, other 5 specifically expressed in hemocytes
• Integrin expression was up-regulated after 20-E injection in hemocytes.

As an important economic insect, Bombyx mori is also a useful model organism for lepidopteran insect. Integrins are evolutionarily conserved from sponges to humans, and play vital roles in many physiological and pathological processes. To explore their diverse functions of integrins in insect, eleven integrins including six α and five β subunits were cloned and characterized from silkworm. Our results showed that integrins from silkworm own more family members compared to other invertebrates. Among those α subunits, integrins α1, α2, and the other four subunits belong to PS1, PS2, and PS3 groups, respectively. The β subunits mainly gather in the insect βν group except the β1 subunit which belongs to the insect β group. Expression profiles demonstrated that the integrins exhibited distinct patterns, but were mainly expressed in hemocytes. α1 and β2 subunits are the predominant ones either in the embryogenesis or larva stages. Interestingly, integrins were significantly up-regulated after stimulated by 20-hydroxyecdysone (20-E) in vivo. These results indicate that integrins perform diverse functions in hemocytes of silkworm. Overall, our results provide a new insight into the functional and evolutionary features of integrins.