Molecular cloning and characterization of a novel marsupial milk protein gene.

The tammar wallaby (Macropus eugenii) produces two different types of milk; "early" milk for the first 180 days and "late" milk for the remaining 150 days of lactation. We report the cloning of the cDNA of a novel whey protein, Late-Lactation Protein (LLP), which is produced during the late phase of lactation. The cDNA was cloned using an oligonucleotide probe deduced from the published partial protein sequence. The cDNA encodes an open-reading frame of 176 amino acids of which the first 18 residues represent a signal peptide. Northern blot analysis revealed a 1kb transcript in late phase lactation but not in the early phase.