Analysis of bovine LAPTM4B mRNA expression in bovine tissues by Northern blot. Total RNA was extracted from various bovine tissues and samples (20 μg/well) were analyzed by Northern blot as described under Materials and Methods. A. The presence of a 1.8 kb transcript corresponding to LAPTM4B mRNA was detected and showed a variable pattern of expression among tissues. B. Comparison of relative steady state levels of bLAPTM4B mRNA expression corrected using 18S rRNA.