Plxnb2^tm1Matl

Targeted mutagenesis using a promoterless gene trap vector ("targeted trapping") was used to insert a 9.4-kb placental alkaline phosphatase (PLAP) secretory cassette into the intron between exons 16 and 17 (counting the exon containing the translational start site as exon 1). This results in transcription of a fusion mRNA joining exons 1-16 of the endogenous gene to the elements of the cassette, comprising a splice acceptor and a transmembrane domain coding sequence followed by the betageo (lacZ/neomycin resistance fusion) cDNA, an internal ribosomal entry site (IRES), and the human PLAP sequence with a polyadenylation signal. Two proteins are translated from this bicistronic transcript: a PLXNB2/Betageo fusion protein that is sequestered in an intracellular compartment of the neuronal cell body; and PLAP, which is expressed on the axonal surface. (J:119485)