زهرا رودباری

THE BMPR1B gene is a significant component in the BMP/SMAD signaling pathway, holding importance in numerous biological functions, especially reproductive processes. In sheep, BMPR1B has been identified as a key gene affecting litter size, influencing prolificacy and fertility [1]. This gene's activity within the BMP/SMAD pathway plays a critical role in regulating essential processes like ovarian follicular development, ovulation, and embryonic growth [2-3]. To investigate this, a study was conducted using network construct to explore the impact of BMPR1B activity and the BMP/SMAD pathway. The research aimed to comprehend the genetic factors influencing litter size in sheep and their implications for breeding and production. The result revealed that BMP ligands bind to BMPR1B, leading to receptor dimerization and activation. Upon ligand binding, BMPR1B forms a heterotetrameric complex with BMPR2, leading to phosphorylation and activation. This activated BMPR1B then phosphorylates receptor-regulated SMADs (R-SMADs), predominantly SMAD1, SMAD5, and SMAD8. These phosphorylated R-SMADs create complexes with SMAD4 (co-SMAD), which subsequently translocate into the nucleus, acting as transcription factors. They regulate gene transcription by binding to specific DNA sequences and interacting with other transcriptional regulators. The activity of BMPR1B and the BMP/SMAD signaling is under stringent regulation by extracellular antagonists, intracellular inhibitors, and feedback mechanisms. Understanding the impact of BMPR1B activity on the BMP/SMAD pathway offers valuable insights into the molecular mechanisms governing fertility traits, specifically litter size, in sheep. The findings also illuminate the intricate interactions within the BMP/SMAD pathway and their role in regulating litter size, providing crucial information for the sheep farming industry.