{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nIn the mouse olfactory system, a specific upstream cis-acting DNA region—here referred to as SPACDR—plays a pivotal role in ensuring that each olfactory sensory neuron expresses only one odorant receptor gene from a clustered array. Functioning as an enhancer element, SPACDR activates the entire odorant receptor gene cluster and mediates a process of stochastic, monoallelic gene choice. Once an odorant receptor gene is selected and its product produced, a negative feedback mechanism is triggered that prevents additional receptor genes within the same cluster from being expressed, thereby enforcing the one receptor–one neuron rule. Notably, experimental disruption of this regulatory region or mutations in the receptor gene disrupt this exclusivity, allowing the aberrant expression of a second receptor, underscoring the critical function of SPACDR in olfactory system development and neuronal wiring."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": ""}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Shou Serizawa, Kazunari Miyamichi, Hiroko Nakatani, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Negative feedback regulation ensures the one receptor-one olfactory neuron rule in mouse."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Science (2003)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1126/science.1089122"}], "href": "https://doi.org/10.1126/science.1089122"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "14593185"}], "href": "https://pubmed.ncbi.nlm.nih.gov/14593185"}]}]}]}