BmToll9, an Arthropod conservative Toll, is likely involved in the local gut immune response in the silkworm, Bombyx mori.
The Toll family of transmembrane proteins mediates signaling during the innate immune response in most animals. Toll9 is widespread in insects and has a unique signature, QHR, in its Toll/interleukin-1 receptor (TIR) domain. The introns in the TIR region are highly conserved among insects, suggesting the antiquity of Toll9 genes. Toll9 of Bombyx mori (BmToll9) was analysed by quantitative real-time RT-PCR. BmToll9 is constitutively expressed in egg, larval and adult stages prior to microbial challenge. BmToll9 is strongly expressed in the different parts of the gut, but weakly expressed in haemocytes, trachea, fat body, malpighian tubule and epidermis, and scarcely expressed in the silk glands. The injection of sterilized 0.85% NaCl solution inhibited BmToll9 expression in most tissues especially during the early responses. Staphylococcus aureus had no or limited effect on the expression of BmToll9 in the silkworm gut and fat body. But in epidermis, trachea, malpighian tubules and haemocytes, the expression of BmToll9 was significantly increased after S. aureus challenge. Infection of Escherichia coli significantly increased the BmToll9 expression in different parts of the gut as well as in epidermis, malpighian tubule and haemocytes. At 48h after feeding of the fungus, Beauveria bassiana, BmToll9 expression was significantly increased. Tissues responses to the injected and ingested bacteria showed that BmToll9 is probably involved in the local gut immune response in the silkworm.
Wu
Shan
S
Research Center for Insect Science, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences Graduate School, Shanghai, People's Republic of China.
Zhang
Xiaofeng
X
Chen
Xiaomei
X
Cao
Pingsheng
P
Beerntsen
Brenda T
BT
Ling
Erjun
E
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D012831:Bombyx / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D041981:Gastrointestinal Tract / Q000276:immunology; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D008969:Molecular Sequence Data; D010802:Phylogeny; D051217:Toll-Like Receptor 9 / Q000235:genetics / Q000276:immunology*
D019476:Insect Proteins; D051217:Toll-Like Receptor 9