Characterization of the murine B7-1 genomic locus reveals an additional exon encoding an alternative cytoplasmic domain and a chromosomal location of chromosome 16, band B5.
The murine B7-1 (mB7-1) molecule expressed on APCs delivers a costimulatory signal for T cell activation through its T cell counter-receptor CD28, resulting in T cell proliferation and IL-2 production. Signaling through the TCR in the absence of CD28 signaling results in T cell anergy. We have analyzed the genomic structure of mB7-1 and here describe the identification of a previously unrecognized sixth exon at the far 3' end of the locus, which encodes an alternative cytoplasmic domain. Reverse transcriptase-PCR amplification of mB7-1 transcripts demonstrates that exon 6 is functionally spliced to the transmembrane-encoding exon 4. Furthermore, using 5' rapid amplification of cDNA ends, we determined that the 5'-untranslated region extends over 1505 bp beyond the previously reported transcriptional start site. In addition, we report the chromosomal location of mB7-1 to chromosome 16, band B5.
Borriello
F
F
Department of Pathology, Brigham and Women's Hospital, Boston, MA 02115.
Freeman
G J
GJ
Edelhoff
S
S
Disteche
C M
CM
Nadler
L M
LM
Sharpe
A H
AH
D017398:Alternative Splicing / Q000235:genetics*; D000595:Amino Acid Sequence; D000818:Animals; D018122:B7-1 Antigen / Q000737:chemistry / Q000235:genetics*; D001483:Base Sequence; D015152:Blotting, Northern; D002874:Chromosome Mapping; D005091:Exons / Q000235:genetics*; D015698:Genomic Library; D006801:Humans; D017403:In Situ Hybridization; D051379:Mice; D008806:Mice, Inbred AKR; D008811:Mice, Inbred DBA; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D016133:Polymerase Chain Reaction / Q000379:methods; D012333:RNA, Messenger / Q000032:analysis; D014158:Transcription, Genetic / Q000235:genetics*
D018122:B7-1 Antigen; D012333:RNA, Messenger