title: Barrier-to-autointegration factor-like (BAF-L): a proposed regulator of BAF.
abstract: Barrier-to-autointegration factor (BAF) is an essential chromatin protein conserved in metazoans. BAF has roles in nuclear assembly, chromatin organization, gene expression, and gonad development and is exploited by retroviruses. BAF forms stable dimers that bind nonspecifically to dsDNA and specifically to LEM-domain proteins (e.g., LAP2beta, emerin, MAN1), homeodomain transcription factors, histones, and lamin A. We characterized a protein named BAF-Like (BAF-L) that in humans is 40% identical to BAF. Overexpression studies in HeLa cells show that BAF-L, like BAF, is a predominantly nuclear protein. Recombinant BAF-L forms stable homodimers and heterodimerizes with BAF in vitro and also interacts with BAF in vivo. BAF-L does not bind significantly to DNA, LAP2beta, or emerin but can form ternary complexes in vitro with BAF plus DNA, or BAF plus LAP2beta. Levels of BAF-L mRNA were high in pancreas and testis, suggesting functions in the germline. BAF-L mRNA was detectable at low levels in eleven other tissues and undetectable in heart and skeletal muscle which are specifically affected by Emery-Dreifuss muscular dystrophy, a disease caused by mutations in either emerin or lamin A. We propose that BAF-L regulates BAF function via heterodimerization and might thereby influence tissue-specific roles of BAF.
authors.affiliation: Department of Cell Biology, Johns Hopkins University School of Medicine, 725 North Wolfe St., Baltimore, MD 21205, USA.
authors.forename: Kathryn E
authors.initials: KE
authors.lastname: Tifft
authors.forename: Miriam
authors.initials: M
authors.lastname: Segura-Totten
authors.forename: Kenneth K
authors.initials: KK
authors.lastname: Lee
authors.forename: Katherine L
authors.initials: KL
authors.lastname: Wilson
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019281:Dimerization; D019084:Fluorescent Antibody Technique, Indirect; D020869:Gene Expression Profiling; D006367:HeLa Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010179:Pancreas / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013737:Testis / Q000378:metabolism; D013946:Thymopoietins / Q000378:metabolism; D014162:Transfection
chemical_list: C501959:BANF1 protein, human; C508180:BANF2 protein, human; D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D009687:Nuclear Proteins; D012333:RNA, Messenger; D013946:Thymopoietins; C092710:emerin; C093413:lamina-associated polypeptide 2; D004247:DNA