Sequence, structure, and chromosomal mapping of the mouse Lgals6 gene, encoding galectin-6.

In the accompanying paper (Gitt, M. A., Colnot, C.

Galectin-4 and galectin-6 are two closely related lectins expressed in mouse gastrointestinal tract.

Galectins are a family of carbohydrate-binding proteins that share a conserved sequence and affinity for beta-galactosides. Some, such as galectin-1, are isolated as dimers and have a single carbohydrate recognition domain (CRD) in each monomer, whereas others, such as galectin-4, are isolated as monomers and have two CRDs in a single polypeptide chain. In the course of studying mouse colon mRNA for galectin-4, we detected a related mRNA that encodes a new galectin that also has two CRDs in a single peptide chain.

Strikingly different localization of galectin-3 and galectin-4 in human colon adenocarcinoma T84 cells. Galectin-4 is localized at sites of cell adhesion.

Two beta-galactoside-binding proteins were found to be prominently expressed in the human colon adenocarcinoma T84 cell line. Cloning and sequencing of one, a 36-kDa protein, identified it as the human homolog of galectin-4, a protein containing two carbohydrate binding domains and previously found only in the epithelial cells of the rat and porcine alimentary tract. The other, a 29-kDa protein, is galectin-3, containing a single carbohydrate binding domain, previously found in a number of different cell types including human intestinal epithelium.

Sequence and mapping of galectin-5, a beta-galactoside-binding lectin, found in rat erythrocytes.

A monomeric rat beta-galactoside-binding lectin previously purified from extracts of rat lung has been localized to erythrocytes, and the cDNA encoding it has been isolated from a rat reticulocyte cDNA library. The deduced amino acid sequence of the cDNA predicts a protein with a M(r) of 16,199, with no evidence of a signal peptide. The deduced sequence is identical to the sequences of seven proteolytic peptides derived from the purified lectin.