title: Identification of chicken nebulin isoforms of the 31-residue motifs and non-muscle nebulin.
abstract: Nebulin is a very large (M(r) 600-900kDa) actin-binding protein that is specific to skeletal muscle, and which is thought to act as a molecular template that regulates the length of sarcomere thin filaments. The 31-residue motif of nebulin contains a unique PEhXRVKXNQ consensus sequence. We have previously identified 11 different human nebulin isoforms of these 31-residue motifs. Here we present the identification of seven different isoforms (types II, III, IVa, IVb, V, VI, and X) of the 31-residue motifs in 15-day-old chicken embryo breast muscle. Isoform types II and III are also expressed in the brain, and type III is also detected in the heart, stomach, and liver. Chicken nebulin contains 11 copies of the 31-residue motif (R1a/b, R2, R3, R4, R5, R6, R7, R8, R9, R10, and R11), whereas human nebulin contains 13 copies. We confirmed the expression of nebulin in the heart, stomach, and brain in 15-day-old chicken embryos by immunofluorescence microscopy. The presence of nebulin in brain was further confirmed by in situ hybridization. These data suggest that there is even more diversity in nebulin isoforms than was previously known; this diversity likely contributes to the distinct actin filament architecture of different tissues.
authors.affiliation: Department of Biomedical Laboratory Science, Inje University, Kimhae 621-749, Republic of Korea.
authors.forename: Young-Mi
authors.initials: YM
authors.lastname: Joo
authors.forename: Min-A
authors.initials: MA
authors.lastname: Lee
authors.forename: Yeong-Mi
authors.initials: YM
authors.lastname: Lee
authors.forename: Myong-Shin
authors.initials: MS
authors.lastname: Kim
authors.forename: So-Young
authors.initials: SY
authors.lastname: Kim
authors.forename: Eun-Hee
authors.initials: EH
authors.lastname: Jeon
authors.forename: Jae-Kyoung
authors.initials: JK
authors.lastname: Choi
authors.forename: Wang-Hee
authors.initials: WH
authors.lastname: Kim
authors.forename: Ho-Chan
authors.initials: HC
authors.lastname: Lee
authors.forename: Byung-In
authors.initials: BI
authors.lastname: Min
authors.forename: Ho-Sung
authors.initials: HS
authors.lastname: Kang
authors.forename: Chong-Rak
authors.initials: CR
authors.lastname: Kim
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D002642:Chick Embryo; D002645:Chickens; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000737:chemistry* / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism; D009928:Organ Specificity; D020033:Protein Isoforms / Q000737:chemistry / Q000378:metabolism; D016415:Sequence Alignment / Q000379:methods; D020539:Sequence Analysis, Protein / Q000379:methods*; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution
chemical_list: D000596:Amino Acids; D009124:Muscle Proteins; D020033:Protein Isoforms; C035620:nebulin