SA-1, a nuclear protein encoded by one member of a novel gene family: molecular cloning and detection in hemopoietic organs.
We report the molecular cloning of a novel gene family. The first member of this family was cloned from a mouse lambda gt11 cDNA library using the B92 monoclonal antibody (mAb) raised against stromal cell extracts. This was followed by RACE-PCR using mRNA from the stromal cell line. A 4 kb cDNA was obtained encoding a unique protein sequence of 1258 aa, that we designate stromal antigen (SA)-1. The human SA-1 gene was cloned by homology from a thymus cDNA library and the sequence of the predicted protein was found to be highly homologous to the murine SA-1 (>98.9%). Another cDNA was cloned and the deduced protein (SA-2) was 71% homologous to SA-1. Northern blot and PCR analysis indicated that on the mRNA level the SA-1 gene is expressed in all tissues analyzed and probably encodes a single transcript. The identification of SA-1 protein in tissues and cells required combined immunoprecipitation and Western blotting using a polyclonal antiserum raised against a predicted peptide of SA-1 and the B92 mAb. Using this assay we identified a protein of about 120 kDa in hemopoietic organs. Subcellular fractionation indicated that SA-1 is a nuclear protein. Thus, despite the ubiquitous expression on the mRNA level, the protein was predominantly detected in hemopoietic organs and may therefore be controlled on a post-transcriptional level. The SA-1 gene described in this study is highly conserved between mouse and man. This implies a crucial function for this protein.
Carramolino
L
L
Pharmacia and UpJohn, R&D, Madrid, Spain.
Lee
B C
BC
Zaballos
A
A
Peled
A
A
Barthelemy
I
I
Shav-Tal
Y
Y
Prieto
I
I
Carmi
P
P
Gothelf
Y
Y
González de Buitrago
G
G
Aracil
M
M
Márquez
G
G
Barbero
J L
JL
Zipori
D
D
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D001854:Bone Marrow Cells / Q000166:cytology / Q000378:metabolism; D002478:Cells, Cultured; D003001:Cloning, Molecular; D005260:Female; D015870:Gene Expression; D015723:Gene Library; D006801:Humans; D008214:Lymphocytes / Q000378:metabolism; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D009374:Neoplasms, Experimental / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins / Q000138:chemical synthesis / Q000235:genetics* / Q000378:metabolism; D010455:Peptides / Q000138:chemical synthesis / Q000276:immunology; D016133:Polymerase Chain Reaction; D011233:Precipitin Tests; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011995:Recombination, Genetic; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D017154:Stromal Cells; D013950:Thymus Gland / Q000378:metabolism; D014158:Transcription, Genetic
D009687:Nuclear Proteins; D010455:Peptides; D012333:RNA, Messenger; C108522:STAG1 protein, human