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General Comment |
Barros SA, et al 2003 report the isolation and structural characterization of the full-length gene and cDNA for a novel
mouse ATP-binding cassette (ABC) transporter, Abca13. The mRNA, isolated from mouse kidney,
is 6.7 kb in size and encodes a protein consisting of 2143 amino acids with a predicted molecular
weight of 240 kDa. The Abca13 gene consists of 44 exons which span 360 kb of genomic sequence.
Abca13 has been mapped to mouse chromosome 11.a2, revealing the human orthologue highly
conserved on a syntenic region of human chromosome 7p12. The deduced mouse Abca13 protein
shows highest amino acid sequence homology to human ABCA1 (50%), ABCA4 (50%), and
ABCA12 (56%). Analysis of the putative Abca13 promoter region revealed potential transcription
factor binding sites associated with myeloid- and lymphoid-derived cell types. mRNA transcript
levels were highest in mouse submaxillary gland, epididymus, ovary, and thymus; with lower levels
in a variety of other tissues. An alternative transcript was discovered in mouse kidney devoid of
exon 11. The removal of exon 11 by post-transcriptional splicing causes a frameshift in the open
reading frame and results in a premature termination codon. The excision of
exon 11 may serve as a regulatory mechanism in kidney, and perhaps other tissues as well. The
molecular characterization of the mouse Abca13 gene will establish the foundation for future
functional studies of the human ABCA13 transporter.
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