생쥐 발생시 고온이 형태형성에 미치는 영향

Abstract

Humans, rats, mice, and other species exposed to hyperthermia exhibit a variety of developmental defects. Development of central nervous system is particularly sensitive to hyperthermia. It is known that hyperthermia induces cell death in embryos and affects gene and protein expression. Homeobox-containing genes (Hox) are a family of regulatory genes encoding transcription factors that primarily play a crucial role during development and direct anterior-posterior axial patterning during embryogenesis. To observe morphological effects and gene expression pattern by heat exposure, day 9 p.c. (post-coitum) mouse embryos were exposed to hyperthermia in culture. Embryos exposed to 43℃ for 15 minutes induced significant decrease in crown-rump length and somite number, and delayed in ear and limb formation. The expression of Hoxa-7 gene in heat-treated embryos did not show any restricted pattern of expression along the anterior-posterior axis, whereas the control group have a distinct anterior boundary of expression, i.e., C5 in the ectoderm-derived spinal ganglia and neural tube, and T3-T5 in the mesoderm-derived prevertebrae. This result indicates that a brief heat shock at specific stage during embryogenesis can interfere with the normal establishment of Hox codes, and subsequently perturb the morphogenesis.