Cloning and characterization of the rat Crisp-1 gene

Rat androgen-regulated acidic epididymal glycoprotein (AEG, also known as P rotein DE, is a product of the Crisp-1 gene. Protein DE is secreted into th e epididymal lumen and binds to sperm heads during their transit through th e epididymis. In experiments reported here, the rat Crisp-1 gene has been c loned and its structure determined. The rat Crisp-1 gene spans 38 kb and co ntains nine exons encoding an 1120 bp epididymal Protein DE mRNA. The bound aries of the protein-coding exons are structurally organized similar to the mouse Crisp-1 gene, except for the 5' untranslated sequence, which is enco ded by one exon in the mouse Crisp-1 gene and two exons in the rat gene. Al l the introns are flanked by AG/GT consensus splice sequences. Crisp-1 is a single-copy gene as shown by the presence of single bands by Southern blot analysis and PCR using rat genomic DNA as template. Recognition sites for steroid hormone receptors are present in the 5' flanking region and in intr on 1, consistent with the known regulation of Protein DE expression by andr ogens. RT-PCR experiments demonstrate three splice variant mRNAs involving the non-coding exon 2. The Crisp-1 gene also produces an mRNA without an ex on 1 sequence by utilizing a transcription start site in intron 1, 5' of th e start of exon 2. All forms of the Crisp-1 mRNA are predicted to encode Pr otein DE. (C) 1999 Elsevier Science B.V. All rights reserved.