The prenatal frontal and parietal bones are distinct organs.

The skull vault is composed of frontal and parietal bones that are connected by flexible sutures that protect the growing brain. Intramembranous ossification in the prenatal skull vault starts by mid-gestation in the mouse, and sutures must remain flexible for normal growth and development. Therefore, the balance of bone formation and remodeling needs to be precisely controlled because premature ossification in the sutures causes craniosynostosis (CS) to develop. CS has a variable clinical presentation where two frontal bones may be fused together, or a frontal bone may be fused to a parietal bone. While most studies focus on the premature suture ossification, we hypothesized that the process of intramembranous ossification in the frontal and parietal bones contributes to the etiology of CS. By bulk RNASeq we identified 536 unique transcripts between the frontal and parietal compartments.Taken together, we propose that the frontal bone is more active in bone remodeling than the parietal bone, and this control is important for temporal onset of intramembranous ossification in the skull vault. To determine the transcriptomic differences between the E15.5 frontal and parietal bones颅盖（skull vault）由额骨与顶骨构成，二者以富有弹性的骨缝相连，可保护处于发育阶段的大脑。小鼠胚胎期颅盖的膜内成骨（Intramembranous ossification）于妊娠中期启动，骨缝需维持弹性以保障正常生长发育。因此，骨形成与骨重塑的平衡必须受到精准调控：若骨缝处出现过早成骨，将引发颅缝早闭（craniosynostosis, CS）。颅缝早闭的临床表现存在异质性，可表现为双侧额骨融合，或额骨与顶骨发生融合。尽管多数研究聚焦于骨缝的过早成骨过程，但本研究假设额骨与顶骨的膜内成骨过程参与了颅缝早闭的病因发生。本研究通过批量RNA测序（bulk RNASeq）在额骨与顶骨区域中鉴定出536个特异性转录本。综上，我们提出相较于顶骨，额骨的骨重塑活性更强，而该调控过程对于颅盖膜内成骨的时序启动至关重要。为探究胚胎第15.5天（E15.5）额骨与顶骨之间的转录组差异