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Debcl, a proapoptotic Bcl-2 homologue, is a component of the Drosophila melanogaster cell death machinery.

Colussi PA, Quinn LM, Huang DC, Coombe M, Read SH, Richardson H, Kumar S - J. Cell Biol. (2000)

Bottom Line: Both proapoptotic and antiapoptotic members of this family are found in mammalian cells, but no such proteins have been described in insects.RNA interference studies indicate that Debcl is required for developmental apoptosis in Drosophila embryos.These results suggest that the main components of the mammalian apoptosis machinery are conserved in insects.

View Article: PubMed Central - PubMed

Affiliation: The Hanson Centre for Cancer Research, Institute of Medical and Veterinary Science, Adelaide, SA 5000, Australia.

ABSTRACT
Bcl-2 family of proteins are key regulators of apoptosis. Both proapoptotic and antiapoptotic members of this family are found in mammalian cells, but no such proteins have been described in insects. Here, we report the identification and characterization of Debcl, the first Bcl-2 homologue in Drosophila melanogaster. Structurally, Debcl is similar to Bax-like proapoptotic Bcl-2 family members. Ectopic expression of Debcl in cultured cells and in transgenic flies causes apoptosis, which is inhibited by coexpression of the baculovirus caspase inhibitor P35, indicating that Debcl is a proapoptotic protein that functions in a caspase-dependent manner. debcl expression correlates with developmental cell death in specific Drosophila tissues. We also show that debcl genetically interacts with diap1 and dark, and that debcl-mediated apoptosis is not affected by gene dosage of rpr, hid, and grim. Biochemically, Debcl can interact with several mammalian and viral prosurvival Bcl-2 family members, but not with the proapoptotic members, suggesting that it may regulate apoptosis by antagonizing prosurvival Bcl-2 proteins. RNA interference studies indicate that Debcl is required for developmental apoptosis in Drosophila embryos. These results suggest that the main components of the mammalian apoptosis machinery are conserved in insects.

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Debcl is a Bcl-2–like protein. A, Genomic structure of the debcl gene at 42E-43A. The noncoding regions of the exons are shown as hatched boxes. B, Debcl protein structure. The relative positions of the three BH domains (BH1, BH2, and BH3) and a membrane anchor (MA) are shown. C, An alignment of the Debcl sequence with Bok and 48A-E Drosophila Bcl-2 homologue. The sequence of the 48A-E homologue was obtained from a partial cDNA sequence isolated by us and the genomic sequence in the data base. The protein sequence of this clone is likely to be incomplete at the NH2 terminus. Residues identical in all three proteins are shown in black boxes and those similar shown in gray boxes. The positions of the two residues in the BH3 domain of Debcl, which were mutated in functional studies in Fig. 5 A, are indicated by an asterisk. D, A Kyte-Doolittle plot of the Debcl protein showing the putative MA region.
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Figure 1: Debcl is a Bcl-2–like protein. A, Genomic structure of the debcl gene at 42E-43A. The noncoding regions of the exons are shown as hatched boxes. B, Debcl protein structure. The relative positions of the three BH domains (BH1, BH2, and BH3) and a membrane anchor (MA) are shown. C, An alignment of the Debcl sequence with Bok and 48A-E Drosophila Bcl-2 homologue. The sequence of the 48A-E homologue was obtained from a partial cDNA sequence isolated by us and the genomic sequence in the data base. The protein sequence of this clone is likely to be incomplete at the NH2 terminus. Residues identical in all three proteins are shown in black boxes and those similar shown in gray boxes. The positions of the two residues in the BH3 domain of Debcl, which were mutated in functional studies in Fig. 5 A, are indicated by an asterisk. D, A Kyte-Doolittle plot of the Debcl protein showing the putative MA region.

Mentions: Debcl and the 48A-E Bcl-2–like proteins were identified as genomic regions encoding putative Bcl-2 family members by TBLASTN searches using Bcl-2 protein sequence (accession numbers of the genomic sequence entries are indicated below). Full-length debcl cDNA sequence of 1,535 bp was obtained from BDGP clones GH01265 and LD12719, purchased from Research Genetics. A 950-bp partial cDNA clone for the 48A-E homologue was isolated from a mixed stage Drosophila embryo cDNA library in λgt11 using a 450-bp probe derived from Drosophila genomic DNA by PCR. Sequencing of this clone confirmed that it also encoded a Bcl-2 family member (Fig. 1 C). However, since the predicted reading frame in the sequence is open at the 5′ end, it is likely that the cDNA clone is not full length.


Debcl, a proapoptotic Bcl-2 homologue, is a component of the Drosophila melanogaster cell death machinery.

Colussi PA, Quinn LM, Huang DC, Coombe M, Read SH, Richardson H, Kumar S - J. Cell Biol. (2000)

Debcl is a Bcl-2–like protein. A, Genomic structure of the debcl gene at 42E-43A. The noncoding regions of the exons are shown as hatched boxes. B, Debcl protein structure. The relative positions of the three BH domains (BH1, BH2, and BH3) and a membrane anchor (MA) are shown. C, An alignment of the Debcl sequence with Bok and 48A-E Drosophila Bcl-2 homologue. The sequence of the 48A-E homologue was obtained from a partial cDNA sequence isolated by us and the genomic sequence in the data base. The protein sequence of this clone is likely to be incomplete at the NH2 terminus. Residues identical in all three proteins are shown in black boxes and those similar shown in gray boxes. The positions of the two residues in the BH3 domain of Debcl, which were mutated in functional studies in Fig. 5 A, are indicated by an asterisk. D, A Kyte-Doolittle plot of the Debcl protein showing the putative MA region.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2169366&req=5

Figure 1: Debcl is a Bcl-2–like protein. A, Genomic structure of the debcl gene at 42E-43A. The noncoding regions of the exons are shown as hatched boxes. B, Debcl protein structure. The relative positions of the three BH domains (BH1, BH2, and BH3) and a membrane anchor (MA) are shown. C, An alignment of the Debcl sequence with Bok and 48A-E Drosophila Bcl-2 homologue. The sequence of the 48A-E homologue was obtained from a partial cDNA sequence isolated by us and the genomic sequence in the data base. The protein sequence of this clone is likely to be incomplete at the NH2 terminus. Residues identical in all three proteins are shown in black boxes and those similar shown in gray boxes. The positions of the two residues in the BH3 domain of Debcl, which were mutated in functional studies in Fig. 5 A, are indicated by an asterisk. D, A Kyte-Doolittle plot of the Debcl protein showing the putative MA region.
Mentions: Debcl and the 48A-E Bcl-2–like proteins were identified as genomic regions encoding putative Bcl-2 family members by TBLASTN searches using Bcl-2 protein sequence (accession numbers of the genomic sequence entries are indicated below). Full-length debcl cDNA sequence of 1,535 bp was obtained from BDGP clones GH01265 and LD12719, purchased from Research Genetics. A 950-bp partial cDNA clone for the 48A-E homologue was isolated from a mixed stage Drosophila embryo cDNA library in λgt11 using a 450-bp probe derived from Drosophila genomic DNA by PCR. Sequencing of this clone confirmed that it also encoded a Bcl-2 family member (Fig. 1 C). However, since the predicted reading frame in the sequence is open at the 5′ end, it is likely that the cDNA clone is not full length.

Bottom Line: Both proapoptotic and antiapoptotic members of this family are found in mammalian cells, but no such proteins have been described in insects.RNA interference studies indicate that Debcl is required for developmental apoptosis in Drosophila embryos.These results suggest that the main components of the mammalian apoptosis machinery are conserved in insects.

View Article: PubMed Central - PubMed

Affiliation: The Hanson Centre for Cancer Research, Institute of Medical and Veterinary Science, Adelaide, SA 5000, Australia.

ABSTRACT
Bcl-2 family of proteins are key regulators of apoptosis. Both proapoptotic and antiapoptotic members of this family are found in mammalian cells, but no such proteins have been described in insects. Here, we report the identification and characterization of Debcl, the first Bcl-2 homologue in Drosophila melanogaster. Structurally, Debcl is similar to Bax-like proapoptotic Bcl-2 family members. Ectopic expression of Debcl in cultured cells and in transgenic flies causes apoptosis, which is inhibited by coexpression of the baculovirus caspase inhibitor P35, indicating that Debcl is a proapoptotic protein that functions in a caspase-dependent manner. debcl expression correlates with developmental cell death in specific Drosophila tissues. We also show that debcl genetically interacts with diap1 and dark, and that debcl-mediated apoptosis is not affected by gene dosage of rpr, hid, and grim. Biochemically, Debcl can interact with several mammalian and viral prosurvival Bcl-2 family members, but not with the proapoptotic members, suggesting that it may regulate apoptosis by antagonizing prosurvival Bcl-2 proteins. RNA interference studies indicate that Debcl is required for developmental apoptosis in Drosophila embryos. These results suggest that the main components of the mammalian apoptosis machinery are conserved in insects.

Show MeSH
Related in: MedlinePlus