Yes you can, provided you have sequences of transcripts of the special tissue. Although it is not possible in Web BLAST, you can use local blast to create a custom database and perform BLAST search.

Yes you can, provided you have sequences of transcripts of the special tissue. Although it is not possible in Web BLAST, you can use local blast to create a custom database and perform BLAST search.

Yes and No.

Yes, you can do as Dhirendra Kumar said. Use a local version of BLAST, build a database of the transcripts form a specific tissue, and align your sequences to this database.

No, you don't know if a transcript is tissue-specific or not. So, you can't say you aligned to tissue-specific transcripts.