CDNA cloning and characterization of S6 kinase and its effect on yolk protein gene expression in the oriental fruit fly Bactrocera dorsalis (Hendel)

• Published in: Archives of insect biochemistry and physiology Vol. 78; no. 4; pp. 177 - 189
• Main Authors: Suganya, R., Chen, Shiu-Ling, Lu, Kuang-Hui
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.12.2011
• Subjects: adults; Amino Acid Sequence; Animals; Bactrocera dorsalis; biosynthesis; cell growth; Cloning, Molecular; Developmental stages; Egg Proteins; Egg Proteins - biosynthesis; eggs; enzymology; Fat body; Fat Body - metabolism; Female; fruit flies; Gene expression; genes; genetics; growth & development; Insect Proteins; Insect Proteins - genetics; Insect Proteins - metabolism; Larva; Larva - enzymology; Larva - growth & development; larvae; Male; messenger RNA; metabolism; Molecular Sequence Data; Ovaries; Oviparity; p70 S6 kinase; Polymerase chain reaction; Protein biosynthesis; Protein kinase; protein synthesis; protein-serine-threonine kinases; Pupa; Pupa - enzymology; Pupa - growth & development; pupae; Rapamycin; Reproduction; Reproductive status; reverse transcriptase polymerase chain reaction; Ribosomal Protein S6 Kinases; Ribosomal Protein S6 Kinases - genetics; Ribosomal Protein S6 Kinases - metabolism; RNA interference; RNA-mediated interference; RNAi; S6K; Sirolimus; Tephritidae; Tephritidae - enzymology; Tephritidae - genetics; Tephritidae - growth & development; Threonine; TOR; TOR protein; yolk protein
• ISSN: 0739-4462; 1520-6327; 1520-6327
• DOI: 10.1002/arch.20446

p70 S6 kinase (S6K), a serine/threonine protein kinase, is a downstream target of target of rapamycin (TOR) gene and an important regulator of protein synthesis responsible for cell growth and reproduction. In this study, a S6K gene, named BdS6K (GenBank Accession No. GQ203802), was isolated from the oriental fruit fly Bactrocera dorsalis (Hendel). Quantitative RT‐PCR showed that BdS6K mRNA is expressed at a higher level in egg than in other developmental stages, as well as in ovary than in fat body. Downregulation of BdS6K activity by rapamycin treatment in larval stage resulted in the developmental defects of larvae, pupae, and adults, with a reduced yolk protein (YP) expression in the fat body throughout the first reproductive cycle with a substantial reduction in ovary size, and also repressed the egg development in female fruit fly. Knockdown of BdS6K gene by RNA interference in the adult significantly decreased the YP expression. These observations support the involvement of BdS6K signaling in the regulation of the YP synthesis and egg development in B. dorsalis. © 2011 Wiley Periodicals, Inc.