Ssq

The Ssq mutation was generated by random transgene insertional mutagenesis using a reporter construct. The reporter construct consisted of Hoxb1 with a 110bp deletion spanning its initiation codon and fused to a human placental alkaline phosphatase sequence. Two integration sites occurred on proximal chromosome 5. The most proximal integration site was in intron 5 of Lmbr1 about 800 kb from Shh and segregates with the homozygous phenotype. About 20kb of intron 5 sequence were duplicated during the course of transgene insertion with the transgene residing between the duplicated segments. Expression level of full length Lmbr1 is reduced to 10-30% of normal levels and ectopic expression of Shh is observed. (J:52453, J:82883, J:150634)