Aggrecan domains expected to traffic through the exocytic pathway are misdirected to the nucleus.

In this article, we report the misdirected targeting of expressed aggrecan domains. Aggrecan, the chondroitin sulfate (CS) proteoglycan of cartilage, normally progresses through the exocytic pathway. Proteins expressed from constructs containing the putative aggrecan signal sequence (i.

Mutations in the large subunit of U2AF disrupt pre-mRNA splicing, cell cycle progression and nuclear structure.

The prp2 gene of fission yeast has previously been shown to encode the large subunit of the splicing factor spU2AF. SpU2AF(59) is an evolutionarily conserved protein that has an arginine/serine-rich region and three RNA recognition motifs (RRMs). We have sequenced three temperature-sensitive alleles of prp2 and determined that the mutations result in single amino acid changes within one of the RRMs or between RRMs.

Effects of vitamin D binding protein-macrophage activating factor (DBP-MAF) infusion on bone resorption in two osteopetrotic mutations.

Osteopetrosis is a heterogeneous group of bone diseases characterized by an excess accumulation of bone and a variety of immune defects. Osteopetrosis (op) and incisors absent (ia) are two nonallelic mutations in the rat which demonstrated these skeletal defects as a result of reduced bone resorption. Osteopetrotic (op) rats have severe sclerosis as a result of reduced numbers of osteoclasts which are structurally abnormal.

Xylosylation is an endoplasmic reticulum to Golgi event.

The subcellular site of xylosylation, the first carbohydrate modification of the core protein that initiates glycosaminoglycan chain synthesis, was characterized in situ. Methods were developed to combine electron microscopic (EM) autoradiography and the radiolabeling of semi-intact chondrocytes. In the accompanying paper, Kearns et al.

Stable heparin-producing cell lines derived from the Furth murine mastocytoma.

Stable cell lines that synthesize heparin have been established from the Furth murine mastocytoma. The parental line (MST) divides in suspension every 14-18 h in growth medium supplemented with fetal bovine serum or defined growth factors. Adherent subclones were selected by adhesion to plastic culture vessels.