Autophagy, apoptosis, and ecdysis-related gene expression in the silk gland of the silkworm (Bombyx mori) during metamorphosis

2010 ◽  
Vol 88 (12) ◽  
pp. 1169-1178 ◽  
Author(s):  
Qingrong Li ◽  
Xiaojuan Deng ◽  
Wanying Yang ◽  
Zhijun Huang ◽  
Gianluca Tettamanti ◽  
...  
Keyword(s):  
Bombyx Mori ◽  
Receptor Gene ◽  
Silk Gland ◽  
Apoptotic Bodies ◽  
Gland Cells ◽  
Cytoplasmic Material ◽  
Transcription Factor Genes ◽  
Insect Metamorphosis ◽  
Apoptosis Pathways ◽  
Silkworm Bombyx Mori

Degeneration of larval-specific tissues during insect metamorphosis has been suggested to be the result of apoptosis and autophagy and is triggered by ecdysteroids. However, the relationship between autophagy and apoptosis pathways and the mechanism of regulation by ecdysteroids remain to be elucidated. This study examined the events of autophagy, apoptosis, and the expression of ecdysis-related genes in the silk gland of the silkworm ( Bombyx mori L., 1758) during the larval to pupal transformation. The results indicated that autophagic features appeared in the silk gland at the wandering and spinning stages of the larvae, whereas the apoptotic features such as apoptotic bodies and DNA fragmentation occurred at the prepupal or early-pupal stages. The autophagic granules fused with each other to form large vacuoles where the cytoplasmic material was degraded. Autophagosomes, autolysosomes, and apoptotic bodies were found later in the degenerating silk-gland cells. Expression of the ecdysone receptor gene BmEcR and the transcription factor genes BmE74A and BmBR-C preceded the onset of autophagy and apoptosis, indicating that they may be responsible for triggering these programmed cell death pathways in the silk gland. The results suggest that both autophagy and apoptosis occur in the silk-gland cells during degeneration, but autophagy precedes apoptosis.

scholarly journals EXTRUSION OF NUCLEAR MATERIALS INTO CYTOPLASM IN THE POSTERIOR SILK GLAND CELLS OF SILKWORM, BOMBYX MORI

1968 ◽  
Vol 36 (3) ◽  
pp. C5-10 ◽  
Author(s):  
Yutaka Tashiro ◽  
Shiro Matsuura ◽  
Takashi Morimoto ◽  
Sunao Nagata
Keyword(s):  
Bombyx Mori ◽  
Silk Gland ◽  
Nuclear Materials ◽  
Gland Cells ◽  
Silkworm Bombyx Mori ◽  
Posterior Silk Gland

TREHALASE ACTIVITY IN THE SILK GLANDS OF THE SILKWORM, BOMBYX MORI (LEPIDOPTERA: BOMBYCIDAE)

1975 ◽  
Vol 107 (12) ◽  
pp. 1311-1314 ◽  
Author(s):  
Shuya Shimada
Keyword(s):  
Bombyx Mori ◽  
Divalent Cations ◽  
Silk Gland ◽  
Trehalase Activity ◽  
Gland Cells ◽  
Silk Glands ◽  
Tunica Propria ◽  
Silkworm Bombyx Mori ◽  
Cu And Zn ◽  
Tunica Intima

Abstract(1) Crude extracts prepared from the silk glands of the silkworm, Bombyx mori L. contain trehalase activity. (2) Trehalase in the silk glands has a pH of 5.5 and a Km of 0.71 mM. The activity of the enzyme is inhibited by divalent cations such as Mn, Cu, and Zn. (3) By histochemical methods, it is shown that trehalase is localized in the periphery of the silk gland cells, especially in the tunica propria and tunica intima. (4) Trehalase activity is low in fifth instar and increases greatly in spinning stages, after which the activity decreases.

Effects of starvation and hormones on DNA synthesis in silk gland cells of the silkworm,Bombyx mori

2015 ◽  
Vol 23 (4) ◽  
pp. 569-578 ◽  
Author(s):  
Yao-Feng Li ◽  
Xiang-Yun Chen ◽  
Chun-Dong Zhang ◽  
Xiao-Fang Tang ◽  
La Wang ◽  
...  
Keyword(s):  
Dna Synthesis ◽  
Bombyx Mori ◽  
Silk Gland ◽  
Gland Cells ◽  
Silkworm Bombyx Mori

Polytene chromosomes in silk gland cells of the silkworm,Bombyx mori

1969 ◽  
Vol 25 (4) ◽  
pp. 384-385 ◽  
Author(s):  
Y. H. Nakanishi ◽  
H. Kato ◽  
S. Utsumi
Keyword(s):  
Bombyx Mori ◽  
Polytene Chromosomes ◽  
Silk Gland ◽  
Gland Cells ◽  
Silkworm Bombyx Mori

scholarly journals CRISPR-Mediated Endogenous Activation of Fibroin Heavy Chain Gene Triggers Cellular Stress Responses in Bombyx mori Embryonic Cells

Insects ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 552
Author(s):  
Wenbo Hu ◽  
Xiaogang Wang ◽  
Sanyuan Ma ◽  
Zhangchuan Peng ◽  
Yang Cao ◽  
...  
Keyword(s):  
Bombyx Mori ◽  
Heavy Chain ◽  
Stress Responses ◽  
Cellular Stress ◽  
Silk Gland ◽  
Cellular Stress Response ◽  
Molar Ratio ◽  
Chain Gene ◽  
Gland Cells ◽  
Cellular Stress Responses

The silkworm Bombyx mori is an economically important insect, as it is the main producer of silk. Fibroin heavy chain (FibH) gene, encoding the core component of silk protein, is specifically and highly expressed in silk gland cells but not in the other cells. Although the silkworm FibH gene has been well studied in transcriptional regulation, its biological functions in the development of silk gland cells remain elusive. In this study, we constructed a CRISPRa system to activate the endogenous transcription of FibH in Bombyx mori embryonic (BmE) cells, and the mRNA expression of FibH was successfully activated. In addition, we found that FibH expression was increased to a maximum at 60 h after transient transfection of sgRNA/dCas9-VPR at a molar ratio of 9:1. The qRT-PCR analysis showed that the expression levels of cellular stress response-related genes were significantly up-regulated along with activated FibH gene. Moreover, the lyso-tracker red and monodansylcadaverine (MDC) staining assays revealed an apparent appearance of autophagy in FibH-activated BmE cells. Therefore, we conclude that the activation of FibH gene leads to up-regulation of cellular stress responses-related genes in BmE cells, which is essential for understanding silk gland development and the fibroin secretion process in B. mori.

P25 gene regulation in Bombyx mori silk gland: two promoter-binding factors have distinct tissue and developmental specificities

1992 ◽  
Vol 12 (12) ◽  
pp. 5768-5777
Author(s):  
B Durand ◽  
J Drevet ◽  
P Couble
Keyword(s):  
Bombyx Mori ◽  
Head Capsule ◽  
Regulatory Elements ◽  
Silk Gland ◽  
Related Factor ◽  
Developmental Studies ◽  
Hormonal Change ◽  
Specific Expression ◽  
Gland Cells ◽  
Gene Status

The gene encoding the silk protein P25 is expressed in the posterior silk gland of Bombyx mori with strict territorial and developmental specificities. The cis-acting regulatory elements previously located within the 441-bp 5' proximal sequence of the gene were examined for protein-binding capacities. We identified two factors, BMFA and SGFB, that lead to prominent band shifts and the target sites for which are included in a region homologous to the fibroin gene enhancer sequence. Analysis of the tissue-specific incidence of both factors showed that BMFA is ubiquitous, whereas SGFB is restricted to the silk gland cells. However, SGFB was found in both posterior and middle silk gland cells and therefore likely directs organ-specific, but not territory-specific, expression. Developmental studies throughout the fourth larval molt, at which the P25 gene status changes from derepressed to repressed, revealed that BMFA is reversibly modified at the transition from intermolt to molt. Indeed, the preexisting BMFA is replaced by a structurally related factor, BMFA', during the 2 h following head capsule apolysis. The exact temporal coincidence of this conversion with the onset of gene repression suggests that BMFA' is involved in transcription inactivation and likely results from a transduction process initiated by the hormonal change at molting.

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