The genomic underpinnings of apoptosis in the silkworm, Bombyx mori

Abstract

BackgroundApoptosis is regulated in an orderly fashion by a series of genes, and has a crucial role in important physiological processes such as growth development, immunological response and so on. Recently, substantial studies have been undertaken on apoptosis in model animals including humans, fruit flies, and the nematode. However, the lack of genomic data for silkworms limits their usefulness in apoptosis studies, despite the advantages of silkworm as a representative of Lepidoptera and an effective model system. Herein we have identified apoptosis-related genes in the silkworm Bombyx mori and compared them to those from insects, mammals, and nematodes.ResultsFrom the newly assembled genome databases, a genome-wide analysis of apoptosis-related genes in Bombyx mori was performed using both nucleotide and protein Blast searches. Fifty-two apoptosis-related candidate genes were identified, including five caspase family members, two tumor necrosis factor (TNF) superfamily members, one Bcl-2 family member, four baculovirus IAP (inhibitor of apoptosis) repeat (BIR) domain family members and 1 RHG (Reaper, Hid, Grim, and Sickle; Drosophila cell death activators) family member. Moreover, we identified a new caspase family member, BmCaspase-New, two splice variants of BmDronc, and Bm3585, a mammalian TNF superfamily member homolog. Twenty-three of these apoptosis-related genes were cloned and sequenced using cDNA templates isolated from BmE-SWU1 cells. Sequence analyses revealed that these genes could have key roles in apoptosis.ConclusionsBombyx mori possesses potential apoptosis-related genes. We hypothesized that the classic intrinsic and extrinsic apoptotic pathways potentially are active in Bombyx mori. These results lay the foundation for further apoptosis-related study in Bombyx mori.

Autophagy precedes apoptosis during the remodeling of silkworm larval midgut

“…Primers for qRT-PCR were designed according to the sequences of the target genes ( Table 2). In detail, we evaluated the expression of autophagy-related genes BmATG5 (GenBank accession number NM_001142487), BmATG6 (NM_0011 42490) and BmATG8 (NM_001046779) [32,60] and apoptosis-related genes BmICE-2 (DQ360829), BmCaspase-4 (HQ456874) and BmIAP (NM_001043559) [61,62].…”

Characterization of cDNAs encoding p53 of Bombyx mori and Spodoptera frugiperda

“…Recently cDNA of Bmp53 was examined in B. mori larvae and cells and these studies suggested that Bmp53 mRNA levels were elevated after UV irradiation and actinomycin D treatment (Zhang et al, 2011).…”

Cloning and characterization of a dronc homologue in the silkworm, Bombyx mori

“…Dronc plays a critical role in developmental and stress-induced apoptotic cell death in Drosophila, by activating the effector caspase DrICE (Hay and Guo, 2006;Cooper et al, 2009;Kumar and Doumanis, 2000). In lepidopteran insects, while effector caspases have been identified from several insects, including S. frugiperda, Trichoplusia ni and Spodoptera littoralis (Ahmad et al, 1997;Hebert et al, 2009;Liu et al, 2005), initiator caspases have not been characterized, although their presence has been suggested in S. frugiperda and Bombyx mori cells (Manji and Friesen, 2001;Huang et al, 2001;LaCount et al, 2000;Tanaka et al, 2008;Zhang et al, 2010;Zoog et al, 2002).…”