BMDREDD REGULATES THE APOPTOSIS COORDINATING WITH BMDAXX, BMCIDE‐B, BMFADD, AND BMCREB IN BMN CELLS

Abstract

The apoptosis mechanisms in mammals were investigated relatively clearly. However, little is known about how apoptosis is achieved at a molecular level in silkworm cells. We cloned a caspase homologous gene named BmDredd (where Bm is Bombyx mori and Dredd is death-related ced-3/Nedd2-like caspase) in BmN cells from the ovary of Bm and analyzed its biological information. We constructed the N-terminal, C-terminal, and overexpression vector of BmDredd, respectively. Our results showed that the transcriptional expression level of BmDredd was increased in the apoptotic BmN cells. Furthermore, overexpression of BmDredd increased the caspase-3/7 activity. Simultaneously, RNAi of BmDredd could save BmN cells from apoptosis. The immunofluorescence study showed that BmDredd located at the cytoplasm in normal cell otherwise is found at the nucleus when cells undergo apoptosis. Moreover, we quantified the transcriptional expressions of apoptosis-related genes including BmDredd, BmDaxx (where Daxx is death-domain associated protein), BmCide-b (where Cide-b is cell death inducing DFF45-like effector), BmFadd (Fadd is fas-associated via death domain), and BmCreb (where Creb is cAMP-response element binding protein) in BmN cells with dsRNA interferences to detect the molecular mechanism of apoptosis. In conclusion, BmDredd may function for promoting apoptosis and there are various regulatory interactions among these apoptosis-related genes.

Three vital RNA functions and interactions in the process of silk gland apoptosis in silkworm Bombyx mori

“…It undergoes a dramatic degeneration after spinning (Matsuura, Morimoto, Nagata, & Tashiro, ). Recently, many studies have elucidated the mechanism from the mRNA levels, some important genes such as Bmatg , BmDredd , and BmEcR were also found regulating the degeneration of the silkgland (R. T. Chen et al, ; R. Chen et al ; Huang et al, ; Zhang et al, , ). Many studies have demonstrated that some mRNAs could induce apoptosis in silkworm cells, but this was not clear enough to reveal why larva‐specific tissues degenerate while others not during the metamorphosis.…”

“…This process involves hormone regulated programmed cell death that is apoptosis (Matsui, Kakei, Iwami, & Sakurai, ). Recently, some apoptosis‐related genes have been investigated in the silkworm silk gland or in silkworm ovary cells (R. T. Chen et al, ; Huang et al, ; Yi et al, ; Zhang et al, ; Zhang, Zhao, Qiao, Pan, & Lu, ). However, except for the function of Bm Dredd in the silk gland (R. Chen et al, ), few papers reported the functions of inhibiting or inducing apoptosis on the individual level of the silkworm.…”

Role of BmDredd during Apoptosis of Silk Gland in Silkworm, Bombyx mori

“…Recently, some evidence has showed that Bm Dredd functions importantly in apoptosis. Its expression level was elevated in actinmycin D induced Bm E cells [17] and in actinmycin D or ultraviolet induced Bm N cells [25]. In addition, overexpression of Bm Dredd caused the increase of caspase3/8-like protease activity in Bm N-SWU1 cells [26].…”

Role of Bm30kc6 gene in cell apoptosis and the silk gland degradation signaling pathway in Bombyx mori L.

“…Moreover, caspase‐3‐like activity was increased in the silk gland by overexpression of BmDredd. Taken together, the results suggest that BmDredd plays a critical role in silk gland apoptosis (R. T. Chen et al, 2016).…”