Casein kinase 2 during early embryonic development in silkworm Bombyx mori: cDNA sequence, gene expression, and enzyme activity

Abstract

To clarify the property of casein kinase 2 (CK2) during early embryonic development in the silkworm, we compared the phosphorylation activities of CK2 in non-diapause and diapause eggs until 60 h after oviposition. In nondiapause eggs, the phosphorylated signals were found at each stage and became progressively stronger through each stage. On the other hand, in diapause eggs, the strongest phosphorylated signals were found at approximately 12 to 24 h after oviposition and became progressively weaker through each stage. To clarify the control mechanism of these enzyme activities, we tried to clone cDNAs encoding α- and β-subunit of CK2 and analyze the gene expressions. The deduced amino acid sequence of the isolated cDNAs comprised 342 and 220 residues, and these sequences showed 85–90% identities to the α- and β-subunit of CK2 in Spodoptera frugiperda. RT-PCR indicated that these genes were expressed in nondiapause and diapause eggs. However, these genes expressions were not parallel with the changes in CK2 activity. These results suggest that the changes in CK2 activity are regulated mainly at the level of post-transcription during embryonic development in Bombyx mori.

• Bombyx mori
• casein kinase 2
• cDNA
• diapause
• protein kinase
• silkworm egg

Acknowledgements

This work was supported by a Grant-in-Aid from the Ministry of Education, Science, and Culture of Japan to H. S. (13760044 and 15580042) and a Nihon University Research Grant for 2004.