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Functional analysis of 30K proteins during silk gland degeneration by a caspase‐dependent pathway in B ombyx
Author(s) -
Ji MM.,
Liu AQ.,
Gan LP.,
Xing R.,
Wang H.,
Sima YH.,
Xu SQ.
Publication year - 2013
Publication title -
insect molecular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.955
H-Index - 93
eISSN - 1365-2583
pISSN - 0962-1075
DOI - 10.1111/imb.12019
Subject(s) - bombyx mori , biology , bombyx , silk , caspase , dna fragmentation , apoptosis , microbiology and biotechnology , proteolysis , cytoplasm , programmed cell death , gene , biochemistry , enzyme , computer science , operating system
The 30K proteins are involved with important functions in the growth and development of B ombyx mori . In this study, the synthesis and regulation of 30K proteins were examined during the degeneration of B ombyx silk glands. On day 3 of the fifth instar, the protein level of 30Kc19 was low, whereas the silk proteins were rapidly synthesized. However, synthesis and accumulation of the 30Kc19 protein significantly increased at the prepupal stage and on day 1 of the pupal stage. At this stage, the silk gland cells were filled with 30Kc19 and genomic DNA. Moreover, the transcript levels of the 30K ‐encoding genes, including 30K c6 , 30Kc12 , 30Kc19 and 30K c23 were up‐regulated during the degeneration of the B ombyx silk glands. During the time that the levels of the 30Kc19 protein were significantly up‐regulated, it is notable that the transcript levels of the BmAtg8 , BmAtg6 and BmDronc genes dramatically increased to regulate the programmed cell death of this gland. On day 1 of the pupal stage, intense fragmentation of genomic DNA occurred in the silk gland cells, and the putative active form of caspase was detected in the cytoplasm, showing the complete degradation of the silk glands in one day. In conclusion, the 30K proteins are synthesized in high concentrations, while proteolysis mediates silk gland degeneration in Bombyx by a caspase‐dependent pathway. We propose that the 30K proteins may be nutrients and energy vectors to be absorbed by the developing tissues of pupae or moths.