The MTCP-1/c6.1B gene encodes for a cytoplasmic 8 kD protein overexpressed in T cell leukemia bearing a t(X;14) translocation.
The t(X;14)(q28;q11.2) translocation is associated with mature T-cell proliferations. Recently this translocation has been shown to implicate the MTCP-1/c6.1B gene on chromosome Xq28, leading to aberrant or overexpressed MTCP-1 transcripts. The potential coding role of this gene was made uncertain by the lack of a long open reading frame in its major transcripts. However, a short 204 bases open reading frame is potentially coding for a 68 amino-acid protein. Here, we show that this open reading frame sequence and the deduced product are well conserved in mouse. A 8 kD protein (p8), which corresponds to the predicted molecular weight was revealed in transient transfectants and in cell lines by Western blotting, using a rabbit antiserum. This product was absent in lymphoblastoid cell lines with deletions of the MTCP-1/c6.1B locus. A dramatic overexpression of p8 was found in leukemic cells from a patient with a t(X;14). This small protein was localized in the cytoplasm by immunofluorescence. In conclusion, MTCP-1 encodes for a cytoplasmic 8 kD product. Its potential role in leukemogenesis is supported by its overexpression in leukemia with t(X;14), but its function remains unknown.
Laboratoire d'Hématologie Moléculaire, Hôpital Saint Louis, Paris, France.
J
J
Soulier
A
A
Madani
V
V
Cacheux
M
M
Rosenzwajg
F
F
Sigaux
M H
MH
Stern
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002883:Chromosomes, Human, Pair 14; D003593:Cytoplasm / Q000378:metabolism; D018076:DNA, Complementary; D006801:Humans; D007106:Immune Sera; D015458:Leukemia, T-Cell / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000235:genetics*; D009857:Oncogenes; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000276:immunology; D014178:Translocation, Genetic; D014407:Tumor Cells, Cultured; D014960:X Chromosome
D018076:DNA, Complementary; D007106:Immune Sera; C082870:MTCP1 protein, human; D009363:Neoplasm Proteins; D011518:Proto-Oncogene Proteins