Alternative splicing of repetitive units is responsible for the polydispersities of integumentary mucin B.1 (FIM-B.1) from Xenopus laevis.
Frog integumentary mucin B.1 (FIM-B.1) represents a polymorphic extracellular mosaic protein which contains tandemly arranged serine/threonine-rich modules as well as cysteine-rich domains. The latter are probably important for oligomerization of FIM-B.1 and have also been found in many proteins of the complement cascade as well as regions homologous to von Willebrand factor. The repetitive modules are targets for extensive O-glycosylation. Previous cDNA cloning experiments clearly established polydispersities within the same individual, which originate from deletions/insertions in the repetitive domain. Here, we analyse part of the corresponding genomic region. Each repetitive unit as well as the cysteine-rich domain is encoded by an individual class 1-1 exon typical of shuffled modules. Alternative splicing of these multiple cassettes creates the polydisperse FIM-B.1 transcripts.
Max-Planck-Institut für Psychiatrie, Abteilung Neurochemie, Martinsried, Germany.
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Joba
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Hoffmann
D017398:Alternative Splicing / Q000235:genetics*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D006031:Glycosylation; D008099:Liver / Q000378:metabolism; D008969:Molecular Sequence Data; D009077:Mucins / Q000737:chemistry*; D016133:Polymerase Chain Reaction; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics; D015183:Restriction Mapping; D029867:Xenopus Proteins; D014982:Xenopus laevis
C065866:MUC19 protein, Xenopus; D009077:Mucins; D029867:Xenopus Proteins