Alternative titles; symbolsINTLLACTOFERRIN RECEPTOR; LFRHL1HGNC Approved Gene Symbol: ITLN1Cytogenetic location: 1q23.3 Genomic coordinates (GRCh38): 1:160,8...
Alternative titles; symbols
HGNC Approved Gene Symbol: ITLN1
Cytogenetic location: 1q23.3 Genomic coordinates (GRCh38): 1:160,876,539-160,885,179 (from NCBI)
▼ Cloning and Expression
By searching databases for homologs of Xenopus XL35, followed by PCR and screening of various cDNA libraries, Lee et al. (2001) cloned human ITLN1 and ITLN2 (609874), which they called HL1 and HL2, respectively. The predicted 313-amino acid ITLN1 protein has an N-terminal signal peptide and 2 N-glycosylation sites. It shares 85% amino acid identity with ITLN2. Northern blot analysis revealed strongest expression of a 1.3-kb transcript in heart, colon, small intestine, and thymus, with lower levels in ovary, testis, and spleen. Immunohistochemical analysis demonstrated expression of ITLN1 in endothelial cells in colon, liver, thymus, and other tissues.
Using affinity chromatography with galactose-sepharose and human placenta, followed by EST database analysis and RT-PCR of placenta mRNA, Tsuji et al. (2001) obtained a cDNA encoding ITLN1, which they called INTL. The deduced protein has a calculated molecular mass of 33 kD and shares 81.5% amino acid identity with the mouse protein. Immunoblot analysis revealed a 40-kD protein under reducing conditions, and glycanase treatment decreased the size to 34 kD.
Suzuki et al. (2001) purified and cloned ITLN1, which they termed LFR, from human fetal intestine. RT-PCR detected high expression in fetal small intestine and adult heart and lower expression in Caco2 colon carcinoma cells.
▼ Gene Function
Tsuji et al. (2001) analyzed the saccharide-binding activity of INTL and determined that INTL is a calcium-dependent lectin with affinity for furanosides, such as galactofuranosyl in bacterial arabinogalactans.
Suzuki et al. (2001) found that binding of recombinant LFR to lactoferrin, a major iron-binding protein in human milk, was at least partially calcium dependent. Binding of lactoferrin and uptake of lactoferrin-bound iron were increased 1.7 and 3.4 times, respectively, in Caco2 cells transfected with LFR compared with mock-transfected cells.
▼ Gene Structure
Tsuji et al. (2001) determined that the ITLN1 gene contains 8 exons.
By genomic PCR analysis and FISH, Lee et al. (2001) mapped the ITLN1 gene to chromosome 1q22-q23. Tsuji et al. (2001) mapped the ITLN1 gene to chromosome 1q21.3-q22 by genomic sequence analysis.