Region-specific expression of multiple lactase-phlorizin hydrolase genes in intestine of rabbit.

We have identified a total of 4 sequences coding for lactase-phlorizin hydrolase (LPH) in the rabbit. Individual rabbits each yielded three different LPH cDNA sequences, or three chromosomal segments containing exon 1 of the LPH gene, representing either three genes or allelic variants of two genes. The three sequences were found in differing proportions in intestinal mRNA depending on the position along the small intestine from which the RNA was isolated. If all these mRNAs are translated, posttranslational mechanisms previously implicated in the regulation of LPH in the rabbit will be acting on different enzyme species in different parts of the intestine. However, we find no evidence for more than one LPH gene in the rat, and have previously shown that humans have only one LPH gene.