cDNA cloning and characterization of LASP1 from silkworm, Bombyx mori, involved in cytoplasmic polyhedrosis virus infection

Full-length cDNA of a LIM and SH3 contained protein 1 (named BmLASP1) was identified from the silkworm, Bombyx mori, for the first time by rapid amplification of cDNA ends. The full-length cDNA of BmLASP1 is 2094 bp, consisting of a 5′-terminal untranslated region (UTR) of 117 bp, and a 3′-UTR of 610 bp with two poly-adenylation signal sequence AATAAA and a poly (A) tail. The BmLASP1 cDNA encodes a polypeptide comprising 455 amino acids, including a LIM domain, two nebulin domains and an SH3 domain. The theoretical isoelectric point is 7.07 and the predicted molecular weight is 51.8 kDa. BmLASP1 has no signal peptide but three potential N-glycosylation sites. Sequence similarity and phylogenic analyses indicated that BmLASP1 belonged to the group of insect LASP1 with a longer linker region which is different from vertebrate LASP1. The LASP1 in silkworm contained eight exons in its coding regions, and the last exon-intron boundary was conserved the same as in mammalian and Ciona intestinalis LASP1 genes. By fluorescent quantitative real-time polymerase chain reaction, the mRNA transcripts of BmLASP1 were mainly detected in the gonad, head, and spiracle, and slightly in the silk gland, vasa mucosa, midgut, fat body, and hemocytes. After silkworm larvae were infected by B. mori cytoplasmic polyhedrosis virus (BmCPV), the relative expression level of BmLASP1 was down-regulated in the midgut. This result suggested that BmLASP1 may play an important role in the response of silkworm to BmCPV infection.

Graphical abstractDownload high-res image (93KB)Download full-size imageHighlights► A novel BmLASP1 gene was first cloned and sequenced from silkworm (Bombyx mori). ► BmLASP1 belongs to the group of insect LASP1 with a longer linker region. ► BmLASP1 transcripts were mainly expressed in head, testicle, ovary and spiracle. ► The relative expression of BmLASP1 was down-regulated during BmCPV infection. ► BmLASP1 may be involved in apoptosis to defend the host from BmCPV proliferation.