Integrin β1 subunit from Ostrinia furnacalis hemocytes: molecular characterization, expression, and effects on the spreading of plasmatocytes.
When lepidopteran larvae are infected by a large quantity of pathogens or parasitized by nonadaptive parasitoids, hemocytes in the hemocoel will encapsulate these foreign invaders. Cellular encapsulation requires hemocytes, particularly plasmatocytes, to change their states from nonadhesive, spherical cells into adhesive, spreading cells. However, it is unclear how the changes of plasmatocytes are regulated. Here we report that the integrin β1 subunit from hemocytes of Ostrinia furnacalis (Ofint β1) plays an important role in regulating the spreading of plasmatocytes. The full length cDNA sequence (4477 bp) of Ofint β1 was cloned from hemocytes. Phylogenetic analysis showed that Ofint β1 belonged to the integrin βPS family of Drosophila melanogaster with highest sequence identity (78.7%) to the β-integrin of Pseudoplusia includens. Structural analysis of the deduced amino acid sequence indicated that Ofint β1 had similar functional domains to known β-integrins in other lepidopteran insects. RT-PCR, Northern blotting, Western blotting and immunohistochemical analyses showed that OfINT β1 was expressed mainly in hemocytes, especially in plasmatocytes, and weakly in fat body, Malpighian tubes and epidermis. After hemocytes had spread onto slides, fewer antibodies to OfINT β1 bound to the surface of plasmatocytes. Furthermore, anti-OfINT β1 serum clearly inhibited the spreading of plasmatocytes. Together these results indicate that OfINT β1 may play an important role in regulating the spreading of plasmatocytes.
Hu
Jian
J
State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou 510275, China.
Zhao
Huafu
H
Yu
Xiaoqiang
X
Liu
Jia
J
Wang
Peng
P
Chen
Jingya
J
Xu
Qiuyun
Q
Zhang
Wenqing
W
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D015153:Blotting, Western; D002449:Cell Aggregation / Q000502:physiology; D003001:Cloning, Molecular; D006434:Hemocytes / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D007150:Immunohistochemistry; D019012:Integrin beta1 / Q000096:biosynthesis* / Q000235:genetics; D007915:Lepidoptera / Q000166:cytology / Q000378:metabolism*; D008858:Microscopy, Phase-Contrast; D008969:Molecular Sequence Data; D010802:Phylogeny; D012313:RNA / Q000737:chemistry / Q000235:genetics; D019105:Random Amplified Polymorphic DNA Technique; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment
D019012:Integrin beta1; D011994:Recombinant Proteins; D012313:RNA