Disease relevance of BM2

• A bicistronic mRNA transcribed from the influenza B virus RNA segment 7 encodes two viral proteins, matrix protein M1 and uncharacterized small protein BM2 [1].
• These results strongly suggest that BM2 functions to capture the M1-vRNP complex at the virion budding site during virus assembly [2].
• Of these, BM2 has recently been found to have ion channel activity and is considered to be a functional counterpart to influenza A virus M2, but the role of BM2 in the life cycle of influenza B virus remains unclear [2].
• The BM2 and NB proteins of Influenza B virus (the B virus) and the CM2 protein of Influenza C virus (the C virus) are structural homologs of the M2 protein of Influenza A virus (the A virus) [3].
• In this study the BM2 protein was characterized by using an antiserum raised to the BM2 protein of influenza virus strain B/Yamagata/1/73 [4].

High impact information on BM2

• Eukaryotic coupled translation of tandem cistrons: identification of the influenza B virus BM2 polypeptide [5].
• To understand the mechanism by which the BM2 protein is generated from influenza B virus RNA segment 7, a mutational analysis of the cloned DNA was performed and the altered DNAs were expressed in eukaryotic cells [5].
• In an effort to explore its function, a number of BM2 mutant viruses were generated by using a reverse genetics technique [2].
• To completely abolish BM2 expression, we generated a mutant M gene whose BM2 open reading frame was deleted [6].
• Although this mutant was not able to replicate in normal MDCK cells, it did replicate in a cell line that we established which constitutively expresses BM2 [6].

Chemical compound and disease context of BM2

• The influenza B virus BM2 protein contains 109 amino acid residues and it is translated from a bicistronic mRNA in an open reading frame that is +2 nucleotides with respect to the matrix (M1) protein [7].

Biological context of BM2

• The amino acid sequence of BM2 contains a hydrophobic region (residues 7-25) that could act as a transmembrane (TM) anchor [7].
• BM2 is the fourth integral membrane protein encoded by the influenza B virus genome [8].

Anatomical context of BM2

• Sucrose gradient flotation and biochemical analyses of the membrane showed that BM2 was tightly associated with cellular membranes as an integral membrane protein [1].
• Immunofluorescence studies of virus-infected cells indicated that BM2 accumulated at the Golgi apparatus immediately after synthesis and then was transported to the plasma membrane through the trans-Golgi network [1].
• We report that a virion component, the BM2 integral membrane protein, when expressed in Xenopus oocytes or in mammalian cells, causes acidification of the cells and possesses ion channel activity consistent with proton conduction [9].
• The BM2 protein of influenza B virus functions as an ion channel, which is suggested to be important for virus uncoating in endosomes of virus-infected cells [6].

References