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IMGT reference sequences in FASTA format:

Amino acid sequences with gaps

The FASTA header contains:
IMGT accession number | gene and allele name | species | functionality | exon name | domain name | domain type | alternative splicing (if it is) | partial (if it is) 
>AY293285|BTLA*01|Mus musculus|F|EX1|L-REGION|
MKTVPAMLGTPRLFREFFILHLGLWSILCEKATKRN
>AY293285|BTLA*01|Mus musculus|F|EX2|[D]|C-LIKE|
DEECEVQLNIKRNSKHSAWT..GELFKIECPVKYCV.....HRPNVTWCKHNGTIWVPLE
VGPQLYTSWEENR..........SVPVFVLHFKPIHL....SDNGSYSCSTNFN...SQV
INSHSVTIHVR
>AY293285|BTLA*01|Mus musculus|F|EX3|CO|
ERTQNSSEHPLI
>AY293285|BTLA*01|Mus musculus|F|EX4|CO+TM+CY|
TVSDIPDATNASGPSTMEERPGRTWLLYTLLPLGALLLLLACVCLLCFLKRIQ
>AY293285|BTLA*01|Mus musculus|F|EX5|CY|
GKEKKPSDLAGRDTNL
>AY293285|BTLA*01|Mus musculus|F|EX6|CY|
VDIPASSRTNHQALPSGTGIYDNDPWSSMQDESELTISLQSERNNQGIVYASLNHCVIGR
NPRQENNMQEAPTEYASICVRS
>BC108964|BTLA*02|Mus musculus|F|EX1|L-REGION|
MKTVPAMLGTPRLFREFFILHLGLWSILCEKATKRN
>BC108964|BTLA*02|Mus musculus|F|EX2|[D]|C-LIKE|
DEECEVQLNIKRNSKHSAWT..GELFKIECPVKYCV.....HRPHVTWCKHNGTIWVPLE
VGPQLYTSWEENR..........SVPVFVLHFKPIHL....SDNGSYSCSTNFN...SQV
INSHSVTIHVR
>BC108964|BTLA*02|Mus musculus|F|EX3|CO|
ERTQNSSEHPLI
>BC108964|BTLA*02|Mus musculus|F|EX4|CO+TM+CY|
TVSDIPDATNASGPSTMEERPGRTWLLYTLLPLGALLLLLACVCLLCFLKRIQ
>BC108964|BTLA*02|Mus musculus|F|EX5|CY|
GKEKKPSDLAGRDTNL
>BC108964|BTLA*02|Mus musculus|F|EX6|CY|
VDIPASSRTNHQALPSGTGIYDNDPWSSMQDESELTISLQSERNNQGIVYASLNHCVIGR
NPRQENNMQEAPTEYASICVRS
>BC108963|BTLA*03|Mus musculus|F|EX1|L-REGION|SplicingB|
MKTVPAMLGTPRLFREFFILHLGLWSILCEKATKRN
>BC108963|BTLA*03|Mus musculus|F|EX2|[D]|C-LIKE|SplicingB|
DEECEVQLNIKRNSKHSAWT..GELFKIECPVKYCV.....HRPNVTWCKHNGTIWVPLE
VGPQLYTSWEENR..........SVPVFVLHFKPIHL....SDNGSYSCSTNFN...SQV
INSHSVTIHVR
>BC108963|BTLA*03|Mus musculus|F|EX3|CO|SplicingB|
ERTQNSSEHPLI
>BC108963|BTLA*03|Mus musculus|F|EX4|CO+TM+CY|SplicingB|
ISDIPDATNASGPSTMEKRPGRTWLLYTLLPLGALLLLLACVCLLCFLKRIQ
>BC108963|BTLA*03|Mus musculus|F|EX5|CY|SplicingB|
GKEKKPSDLAGRDTNL
>BC108963|BTLA*03|Mus musculus|F|EX6|CY|SplicingB|
VDIPASSRTNHQALPSGTGIYDNDPWSSMQDESELTISLQSERNNQGIVYASLNHCVIGR
NPRQENNMQEAPTEYASICVRS
>AY293285|BTLA*04|Mus musculus|F|EX1|L-REGION|SplicingB|
MKTVPAMLGTPRLFREFFILHLGLWSILCEKATKRN
>AY293285|BTLA*04|Mus musculus|F|EX2|[D]|C-LIKE|SplicingB|
DEECPVQLTITRNSKQSART..GELFKIQCPVKYCV.....HRPNVTWCKHNGTICVPLE
VSPQLYTSWEENQ..........SVPVFVLHFKPIHL....SDNGSYSCSTNFN...SQV
INSHSVTIHVT
>AY293285|BTLA*04|Mus musculus|F|EX3|CO|SplicingB|
ERTQNSSEHPLI
>AY293285|BTLA*04|Mus musculus|F|EX4|CO+TM+CY|SplicingB|
ISDIPDATNASGPSTMEERPGRTWLLYTLLPLGALLLLLACVCLLCFLKRIQ
>AY293285|BTLA*04|Mus musculus|F|EX5|CY|SplicingB|
GKEKKPSDLAGRDTNL
>AY293285|BTLA*04|Mus musculus|F|EX6|CY|SplicingB|
VDIPASSRTNHQALPSGTGIYDNDPWSSMQDESELTISLQSERNNQGIVYASLNHCVIGR
NPRQENNMQEAPTEYASICVRS