RAG-1 interacts with the repeated amino acid motif of the human homologue of the yeast protein SRP1.
Genes for immunoglobulins and T-cell receptor are generated by a process known as V(D)J recombination. This process is highly regulated and mediated by the recombination activating proteins RAG-1 and RAG-2. By the use of the two-hybrid protein interaction system, we isolated a human protein that specifically interacts with RAG-1. This protein is the human homologue of the yeast SRP1 (suppressor of a temperature-sensitive RNA polymerase I mutation). The SRP1-1 mutation is an allele-specific dominant suppressor of a temperature-sensitive mutation in the zinc binding domain of the 190-kDa subunit of Saccharomyces cerevisiae RNA polymerase I. The human SRP cDNA clone was used to screen a mouse cDNA library. We obtained a 3.9-kbp cDNA clone encoding the mouse SRP1. The open reading frame of this cDNA encodes a 538-amino acid protein with eight degenerate repeats of 40-45 amino acids each. The mouse and human SRP1 are 98% identical, while the mouse and yeast SRP1 have 48% identity. After cotransfection of the genes encoding RAG-1 and human SRP1 into 293T cells, a stable complex was evident. Deletion analysis indicated that the region of the SRP1 protein interacting with RAG-1 involved four repeats. The domain of RAG-1 that associates with SRP1 mapped N-terminal to the zinc finger domain. Because this region of RAG-1 is not required for recombination and SRP1 appears to be bound to the nuclear envelope, we suggest that this interaction helps to localize RAG-1.
Cortes
P
P
Rockefeller University, New York, NY 10021.
Ye
Z S
ZS
Baltimore
D
D
D000595:Amino Acid Sequence; D000818:Animals; D004252:DNA Mutational Analysis; D015329:Gene Rearrangement, T-Lymphocyte; D018398:Homeodomain Proteins; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism*; D011485:Protein Binding; D011506:Proteins / Q000378:metabolism*; D011948:Receptors, Antigen, T-Cell / Q000235:genetics; D011995:Recombination, Genetic; D012091:Repetitive Sequences, Nucleic Acid; D012441:Saccharomyces cerevisiae / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D013329:Structure-Activity Relationship; D028901:alpha Karyopherins
D018398:Homeodomain Proteins; D009687:Nuclear Proteins; D011506:Proteins; D011948:Receptors, Antigen, T-Cell; D028901:alpha Karyopherins; C064658:RAG-1 protein