EXPRESSION OF ALTERNATIVELY SPLICED HUMAN LATENT TRANSFORMING-GROWTH-FACTOR-BETA BINDING PROTEIN-1

Latent transforming growth factor beta binding protein-1 (LTBP1) is im portant in regulating the localisation and activation of transforming growth factor beta (TGF beta), Three forms of LTBP1 mRNA have previous ly been described, LTBP1L, LTBP1S and LTBP Delta 53. Here, we have ana lysed the LTBP1 coding sequence and identified two other spliced forms , LTBP1 Delta 55 and LTBP1 Delta 41. LTBP1 Delta 55 is a short form of LTBP1L which lacks 55 amino acids including two consensus N-glycosyla tion sites and LTBP1 Delta 41 is a form of LTBP1 which lacks the 12th EGF-like repeat. Furthermore, sequencing of genomic clones showed that splicing to generate LTBP1L occurs using an intra-exonic 3' splice ac ceptor site in the first coding exon of LTBP1S and that LTBP1 Delta 55 arises from the alternative use of an exonic 3' splice acceptor site at the end of the following intron. LTBP1 Delta 41 arises from skippin g the exon which encodes the 12th EGF-like repeat. LTBP1 Delta 55 and LTBP1 Delta 41 mRNA are expressed in a wide variety of human tissues b ut the proportions of each splice form vary in the tissues. (C) 1998 F ederation of European Biochemical Societies.