Fig. 2.

Isolation of MAP1B promoter region using the linker-dependent genomic walking method. Primers and their relative positions are shown schematically in A. Rat genomic DNA was digested with a mixture of BglII, XbaI, and BamHI, annealed with p4, extended with Klenow fragment, and then ligated with the unique linkers LMPCR1 and LMPCR2. First-round PCR amplification with primers p5 and LMPCR1 (B) and the corresponding Southern blot (C) show a smear with no clearly distinct bands in lane S. Second-round PCR amplification was performed using p6 and LMPCR1 as primers and first-round PCR products as templates (D) with the corresponding Southern blot (E). Lanes 1 and 2 in D and E show two distinct PCR products of 495 and 582 bp. M is a 100 bp DNA ladder.