Identification of cDNA clones that encode hLAMP-1, a component of the particulate matrix associated with cardiac mesenchyme formation.

The heart extracellular matrix protein hLAMP-1 (lectin-associated matrix protein in the heart) is a component of the particulate matrix that activates the AV endothelium prior to its transformation into mesenchyme within the atrioventricular canal and proximal outflow tract of the heart. The role of hLAMP-1 in this process has yet to be determined, in part because of the limited amount of material available for analysis. To overcome this liability, a monoclonal antibody to hLAMP-1 has been used to recognize proteins expressed by cDNA clones. The isolated cDNAs encode an mRNA consistent with previously published immunohistochemical results. Expression profiles of these clones by in situ hybridization revealed staining in areas of the heart that expressed hLAMP-1 by immunocytochemistry. Taken together, these results suggest that these clones, which represent an expressed sequence tag for hLAMP-1, should provide the basis for isolating a full-length cDNA of hLAMP-1, a prerequisite for determining the functional role of this protein in heart development.