EXPRESSION OF PG-M(V3), AN ALTERNATIVELY SPLICED FORM OF PG-M WITHOUTA CHONDROITIN SULFATE ATTACHMENT REGION IN MOUSE AND HUMAN TISSUE

We showed previously that the alternative splicing of chondroitin sulf ate attachment domains (CS alpha and CS beta) yielded multiforms of th e PG-M core protein in mouse. A transcript encoding a new short form o f the core protein PG-M(V3) was found in various mouse tissues using p olymerase chain reaction. DNA sequences of the polymerase chain reacti on products suggested that PG-M(V3) had no chondroitin sulfate attachm ent domain, PG-(V3) was also detected in various human tissues. The pr esence of a transcript for PG-M(V3) was further supported by Northern blot analysis. Southern blot analysis confirmed that multiforms of the PG-M core protein, including PG-M(V3), were derived hom a single geno mic locus by an alternative splicing mechanism. Because PG-M(V3) has n o chondroitin sulfate attachment region, which is the most distinctive portion of a proteoglycan molecule, this form may have a unique funct ion.