Isolation and characterization of the genes encoding mouse and human type-5 acid phosphatase

Abstract

The gene (mT5AP) encoding murine type-5 acid phosphatase has been isolated and completely sequenced while the gene (h T5 AP) encoding human T5AP has been partly sequenced. The murine gene spans 4 kb and contains five exons. Exon 1 is completely non-coding and exon 2 starts with the initiation codon in both m T5AP and h T5AP. The positions of the intron/exon boundaries are completely conserved between m T5 AP and h T5 AP, but are distinct from the gene encoding the related porcine protein, uteroferrin (Utf). There is strong homology at both the nucleotide (nt) and amino acid (aa) levels between the inferred mouse cDNA and the sequences of rat T5AP and hT5AP, and pig Utf. The m T5 AP and h T5 AP genes were found to have multiple transcription start points ( tsp) by primer extension analysis, consistent with the absence of a consensus TATA box. The sequences for the 5'-flanking regions of m T5 AP and h T5 AP were determined to −1.6 and −1.0 kb, respectively, relative to the tsp. A 2-kb segment of the mT5AP 5' flanking region linked to a luciferase-encoding reporter gene ( Luc) was sufficient to direct tissue-specific transcription in the mouse macrophage cell line, RAW264. Significant sequence similarity between the m T5 AP and h T5 AP promoters is restricted to the most proximal 200 bp, which also resembles the porcine Utf gene, and a 300-bp segment 700 bp upstream. A progesteroneresponse element is present only in the mouse promoter and the estrogen- and iron-response elements described previously in the pig gene are absent from both the mouse and human genes. These differences may result in distinctive regulation of T5 AP and Utf expression.