Identifying and characterizing a five‐gene cluster of ATP‐binding cassette transporters mapping to human chromosome 17q24: a new subgroup within the ABCA subfamily

Abstract Introduction The ATP‐binding cassette (ABC) gene superfamily encodes a series of transporter proteins that move a wide variety of substances across extra‐ and intracellular membranes. Forty‐eight known human ABC genes can be divided into seven phylogenetically distinct subfamilies. The ABCA gene subfamily is found exclusively in multicellular eukaryotes. Results We report here on a unique tandem array of five ABCA genes on chromosome 17q24 defining a phylogenetically distinct group. This is the largest cluster of mammalian ABC genes described to date. They are arranged head‐to‐tail and have similar intron/exon organization in both mouse and human. Northern analysis reveals a heterogeneous pattern of expression in human tissues, with ABCA5 and ABCA10 expressed in skeletal muscle, ABCA6 in the liver, ABCA9 in the heart, and ABCA8 in ovaries. This suggests that these proteins have distinct functions.