Identification of a novel nuclear speckle-type protein, SPOP.
A novel antigen recognized by serum from a scleroderma patient was identified by expression cloning from the HeLa cell cDNA library. The cloned cDNA encoded a 374-amino acid protein with a relative molecular mass of 47,000 and a predicted amino acid sequence 62.7% identical to the hypothetical protein of Caenorhabditis elegans, T16H12.5. The deduced amino acid sequence had a typical POZ domain and an unidentified region conserved during evolution. No zinc finger or RNA recognition motifs were found in this clone. The 2 kbp mRNA encoding the novel clone SPOP (speckle-type POZ protein) was found to be expressed in all human tissues examined. HA-tagged SPOP, transfected and overexpressed in COS7 cells, exhibited a discrete speckled pattern in the nuclei and was co-localized with the splicing factor, snRNP B'/B. Deletion analysis revealed that both the POZ domain and the evolutionarily conserved region at the amino-terminus are required for the nuclear speckled accumulation of SPOP.
Nagai
Y
Y
Department of Endocrinology, Medical Research Institute, Tokyo Medical and Dental University, Japan.
Kojima
T
T
Muro
Y
Y
Hachiya
T
T
Nishizawa
Y
Y
Wakabayashi
T
T
Hagiwara
M
M
D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D017173:Caenorhabditis elegans; D003001:Cloning, Molecular; D017124:Conserved Sequence; D018076:DNA, Complementary; D019143:Evolution, Molecular; D015723:Gene Library; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000096:biosynthesis* / Q000737:chemistry; D012333:RNA, Messenger / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry; D012097:Repressor Proteins; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D016324:Sequence Tagged Sites; D014158:Transcription, Genetic; D014162:Transfection
D018076:DNA, Complementary; D009687:Nuclear Proteins; D012333:RNA, Messenger; D011994:Recombinant Proteins; D012097:Repressor Proteins; C509761:SPOP protein, human