Isao Yamamura

Separate Cis-acting DNA Elements Control Cell Type- and Tissue-specific Expression of Collagen Binding Molecular Chaperone HSP47

HSP47 is a collagen-binding heat shock protein and is assumed to act as a molecular chaperone in the biosynthesis and secretion of procollagen. As the synthesis of HSP47 is closely correlated with that of collagen in various cell lines and tissues, we performed a promoter/reporter assay using HSP47-producing and nonproducing cells. 280 base pairs (bp(s)) of upstream promoter were shown to be necessary for the basal expression but not to be enough for the cell type-specific expression. When the first and the second introns were introduced downstream of this 280-bp region, marked up-regulation of the reporter activity was observed in HSP47-producing cells but not in nonproducing cells. This was confirmed in transgenic mice by staining the lacZ gene product under the control of the 280-bp upstream promoter and the introns. Staining was observed in skin, chondrocytes, precursor of bone, and other HSP47/collagen-producing tissues. A putative Sp1-binding site at −210 bp in the promoter, to which Sp3 and an unidentified protein bind, was shown to be responsible for this up-regulation when combined with the introns. However no difference in the binding to this probe was observed between HSP47-producing and nonproducing cells. The responsible region for cell type-specific up-regulation was found to be located in a 500-bp segment in the first intron. On electrophoresis mobility shift assay using this 500-bp probe, specific DNA-protein complexes were only observed in HSP47-producing cell extracts. These results suggest that two separate elements are necessary for the cell type-specific expression of the hsp47 gene; one is a putative Sp1-binding site at −210 bp necessary for basal expression, and the other is a 500-bp region within the first intron, required for cell type-specific expression.

Synovial Chondromatosis of the Lower Compartment of the Temporomandibular Joint

Abstract This report is of a 53-year-old man with synovial chondromatosis of the lower joint compartment of the left temporomandibular joint, a rare condition. The patient presented with pain. Objective findings revealed mild impairment of jaw opening, a 5-mm shift of the mandibular midline towards the contralateral side, and a posterior open bite on the affected side. T2-weighted magnetic resonance imaging was useful for diagnosis. Open surgery was successfully performed and the postoperative course has been uneventful.

Synovial chondromatosis associated with osteochondroma of the mandibular condyle.

41歳女性に発現した下顎頭骨軟骨腫に合併する稀な滑膜骨軟骨腫症の1例を報告した。下顎顔面非対称を主訴として来院し, X線ならびにCT画像から右側下顎頭の肥大とその前方に複数の骨様遊離体がみられた。手術時, 上関節腔には明らかな異常はなく, 下関節腔にのみ病変が認められた。術式としては下顎頭切除と7つの遊離体摘出を行った。