Details

Autor(en) / Beteiligte

• Bialek, Peter Edward

Titel

Investigating the molecular mechanisms of muscle and skeletal development

Ort / Verlag

ProQuest Dissertations Publishing

Erscheinungsjahr

2001

Link zum Volltext

• ProQuest

Quelle

ProQuest Dissertations & Theses A&I

Beschreibungen/Notizen

• The myogenic factor, myf5, is expressed transiently during development in mice and is only barely detectable after birth. Gene targeting experiments show that myf5 is involved in the commitment to the myogenic lineage. To further investigate its function, I have generated transgenic mice over-expressing myf5 in muscle during development and postnatally. These mice are viable and do not display overt muscle abnormalities. However, they are deficient in repairing muscle following injury as characterized by delayed formation of myotubes, as well as by abnormal collagen formation and calcium phosphate deposition. In addition, they exhibit a decrease in numbers of myosatellite cells as compared to wild-type littermates. Furthermore, expression of proliferating cell nuclear antigen (PCNA) can be detected in newly formed multinucleated myotubes in these transgenic animals, suggesting that the transition from proliferating myoblasts to terminally differentiated myotubes is slowed. During my transgenic studies, I have identified a novel insertional mouse mutant with abnormal skeletal development. These mice displayed a characteristic kinked tail and developed kyphoscoliosis, and the disrupted locus is designated as kkt for “kyphoscoliosis kinked tail”. Although the skeletal abnormalities of these mice are similar to Pax-1 mutant mice, undulated, the structure and expression of Pax-1 is normal in kkt mice. The un and kkt mutations do not fully complement each other, suggesting that kkt may function in concert with Pax-1 during skeletal development. I have isolated genomic clones spanning the transgene integration site and identified a genomic fragment of 1.1kb containing transcribed sequence as revealed by reverse northern analysis. This genomic sequence is absent in kkt mice but is present in wild-type animals as well as human and chicken, suggesting that kkt is conserved among different species. This sequence also detected a 2.1kb transcript in early embryos. Our results suggested that kkt is involved in skeletal development and identification of its cDNA will help understand the underlying mechanism.