Isolation and expression of a gene encoding L-14-II, a new human soluble lactose-binding lectin.
In the course of screening a human hepatoma cDNA library with antibody raised against a mammalian lectin with subunit molecular weight of about 14,000, we detected a partial cDNA encoding a related but distinct protein that was possibly a homologous lectin (Gitt and Barondes, 1986). We here report the isolation and sequencing of a full-length cDNA for this protein from a HepG2 cDNA library. The cDNA encodes a protein with subunit molecular weight of 14,650. Expression of the coding sequence in Escherichia coli yields a product that binds to a lactose affinity column and is specifically eluted with lactose, confirming that this new protein is a lectin. Like its well studied relative, here called L-14-I, the new lectin, L-14-II, exists as a homodimer in solution. The two related human lectins have 43% amino acid sequence identity. The genomic DNA encoding L-14-II (LGALS2) contains four exons with similar intron placement to L-14-I (LGALS1); but the genomic upstream region, which contains several sequences characteristic of regulatory elements, differs significantly from L-14-I.
Gitt
M A
MA
Department of Psychiatry, Langley Porter Psychiatric Institute, University of California, San Francisco 94143.
Massa
S M
SM
Leffler
H
H
Barondes
S H
SH
D000595:Amino Acid Sequence; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D002850:Chromatography, Gel; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics; D037161:Galectins; D006388:Hemagglutinins / Q000235:genetics*; D006801:Humans; D037102:Lectins / Q000302:isolation & purification / Q000378:metabolism*; D008969:Molecular Sequence Data; D010957:Plasmids; D012313:RNA / Q000235:genetics; D014407:Tumor Cells, Cultured
D037161:Galectins; D006388:Hemagglutinins; D037102:Lectins; D012313:RNA; D004247:DNA