Expression profile of BBS7. A, Northern blotting of a human 3′ UTR probe showing an ∼2.7-kb species expressed in low-to-moderate levels in multiple human tissues. B, RT-PCR analysis of the two alternatively spliced isoforms in 17 adult and 8 fetal tissues. The short isoform (sBBS2L1) is ubiquitously expressed, whereas the long isoform (lBBS2L1) is expressed in numerous, but not all, tissues.