A novel protein derived from the MUC1 gene by alternative splicing and frameshifting.
Genes that have been designated the name "MUC" code for proteins comprising mucin domains. These proteins may be involved in barrier and protective functions. The first such gene to be characterized and sequenced is the MUC1 gene. Here we report a novel small protein derived from the MUC1 gene by alternative splicing that does not contain the hallmark of mucin proteins, the mucin domain. This protein termed MUC1/ZD retains the same N-terminal MUC1 sequences as all of the other known MUC1 protein isoforms. The common N-terminal sequences comprise the signal peptide and a subsequent stretch of 30 amino acids. In contrast, the MUC1/ZD C-terminal 43 amino acids are novel and result from a reading frameshift engendered by a splicing event that forms MUC1/ZD. The expression of MUC1/ZD at the protein level in human tissues is demonstrated by Western blotting, immunohistochemistry, immunoprecipitation, and an ELISA. Utilization was made of affinity-purified MUC1/ZD-specific polyclonal antibodies as well as two different monoclonal antibodies that are monospecific for the MUC1/ZD protein. The MUC1/ZD protein is expressed in tissues as an oligomeric complex composed of monomers linked by disulfide bonds contributed by MUC1/ZD cysteine residues. MUC1/ZD protein expression did not parallel that of the tandem-repeat array-containing MUC1 protein. Results presented here demonstrate for the first time the expression of a novel MUC1 protein isoform MUC1/ZD, which is generated by an alternative splicing event that both deletes the tandem-repeat array and leads to a C-terminal reading frameshift.
Levitin
Fiana
F
Department of Cell Research and Immunology, Tel-Aviv University, Ramat Aviv 69978, Israel.
Baruch
Amos
A
Weiss
Mordechai
M
Stiegman
Keren
K
Hartmann
Mor-Li
ML
Yoeli-Lerner
Merav
M
Ziv
Ravit
R
Zrihan-Licht
Sheila
S
Shina
Sima
S
Gat
Andrea
A
Lifschitz
Beatrice
B
Simha
Moshe
M
Stadler
Yona
Y
Cholostoy
Alina
A
Gil
Benny
B
Greaves
David
D
Keydar
Iafa
I
Zaretsky
Joseph
J
Smorodinsky
Nechama
N
Wreschner
Daniel H
DH
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry; D001483:Base Sequence; D015153:Blotting, Western; D002460:Cell Line; D045744:Cell Line, Tumor; D003001:Cloning, Molecular; D003545:Cysteine / Q000737:chemistry; D018076:DNA, Complementary / Q000378:metabolism; D004220:Disulfides; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D016368:Frameshift Mutation; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D006825:Hybridomas / Q000378:metabolism; D015151:Immunoblotting; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D051379:Mice; D008957:Models, Genetic; D008969:Molecular Sequence Data; D018396:Mucin-1 / Q000737:chemistry* / Q000235:genetics*; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D011994:Recombinant Proteins; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012867:Skin / Q000378:metabolism
D000911:Antibodies, Monoclonal; D018076:DNA, Complementary; D004220:Disulfides; D018396:Mucin-1; D020033:Protein Isoforms; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D049452:Green Fluorescent Proteins; D003545:Cysteine