Identification of two putative novel folate receptor genes in humans and mouse

Utilizing a 'database mining' strategy to detect novel folate receptors (FR ), we identified two potential novel members in the mouse and human. The mo use gene (Folbp3) was sequenced and found to predict a 28.2 kDa protein tha t consists of 244 amino acids that is highly expressed in both the thymus a nd spleen, suggesting a potential role in the immune system. The human gene (FR-delta) is mapped to chromosome 11q14, and predicts a 27.7 kDa protein that is comprised of 241 amino acids. However, expression of the human gene was not detected in 59 samples from both adult and embryonic tissue source s, suggesting a highly restricted spatial/temporal expression pattern, an a lternatively spliced variant or an additional FR pseudogene. Using T31 mous e radiation hybrid mapping, Folbp3 was mapped to a region on mouse chromoso me 9 that is syntenic to human chromosome 19p13. As the chromosomal locatio ns of murine Folbp1 and Folbp2 genes were previously unknown, we utilized t he same approach and mapped both genes to a region of mouse chromosome 7 th at is syntenic to the human FR loci on chromosome 11q13. (C) 2000 Elsevier Science B.V. All rights reserved.