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General Comment |
During TBLASTN searches of the publicly available EST data
bases using the amino acid sequence of the mouse Boo/Diva
as a query, the authors discovered an EST clone (GenBankTM
accession number AA098865) encoding a predicted
polypeptide harboring a BH1 domain. PCR methods were
used to obtain cDNAs containing the complete ORF
corresponding to a 204-amino acid protein. Bcl-B contains four Bcl-2 Homology (BH) domains (BH1, BH2, BH3,
BH4) and a predicted carboxyl-terminal transmembrane ( TM ) domain. The
BCL-B mRNA is widely expressed in adult human tissues. The Bcl-B protein
binds Bcl-2, Bcl-XL, and Bax but not Bak. In transient transfection assays,
Bcl-B suppresses apoptosis induced by Bax but not Bak. Deletion of the TM
domain of Bcl-B impairs its association with intracellular organelles and
diminishes its anti-apoptotic function. Bcl-B thus displays a unique pattern of
selectivity for binding and regulating the function of other members of the Bcl-2
family.
Northern blot analysis indicated that Bcl-B is expressed in multiple tissues, including the ovary.
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