Project description:Collagen XII, belonging to the fibril-associated collagens, is a homotrimeric secreted extracellular matrix (ECM) protein encoded by the COL12A1 gene. Mutations in the human COL12A1 gene cause an Ehlers-Danlos/myopathy overlap syndrome leading to skeletal abnormalities and muscle weakness. Here, we studied the role of collagen XII in joint pathophysiology by analyzing collagen XII deficient mice and human patients. We found that collagen XII is widely expressed across multiple connective tissue of the developing joint. Lack of collagen XII in mice destabilizes tendons and the femoral trochlear groove to induce patellar subluxation in the patellofemoral joint. These changes are associated with an ECM damage response in tendon and secondary quadriceps muscle degeneration. Moreover, patellar subluxation was also identified as a clinical feature of human patients with collagen XII deficiency. The results provide an explanation for joint hyperlaxity in mice and human patients with collagen XII deficiency.
Project description:As part of the ENCODE consortium the GENCODE project is producing a reference gene set through manual and automated gene prediction. Selected transcript models are verified experimentally by RT-PCR amplification of at least one of their unique splice junctions followed by sequencing. The experiment targets are manually annotated transcripts with novel or putative status, non-pseudogene biotype and unique splice junctions not validated previously. For Batch XII 416 splice junctions from GENCODE15 (released January 2013) were chosen for experimental verification.
Project description:Human-specific changes in specific Siglecs is one of the reasons put forth as molecular mechanisms that could explain human proneness to developing cancers. The SIGLEC12 gene, which encodes the Siglec-XII protein mainly found on epithelial cells, has a fixed homozygous missense mutation in a critical arginine renders unable to recognize its natural ligand. Additionally, the gene harbors a polymorphic frameshift mutation that eliminates expression of the full-length protein in most humans. We hypothesized that dysfunctional Siglec-XII is involved in cancer progression in humans' epithelia. Here we report that the forced expression of human Siglec-XII in caco-2 cells showed that differentially expressed genes in Siglec-XII cells were enriched for diverse bioenergetic processes.