Progenitor cells of the olfactory receptor neuron lineage.
The olfactory epithelium of the mouse has many properties that make it an ideal system for studying the molecular regulation of neurogenesis. We have used a combination of in vitro and in vivo approaches to identify three distinct stages of neuronal progenitors in the olfactory receptor neuron lineage. The neuronal stem cell, which is ultimately responsible for continual neuron renewal in this system, gives rise to a transit amplifying progenitor identified by its expression of a transcription factor, MASH1. The MASH1-expressing progenitor gives rise to a second transit amplifying progenitor, the Immediate Neuronal Precursor, which is distinct from the stem cell and MASH1-expressing progenitor, and gives rise quantitatively to olfactory receptor neurons. Regulation of progenitor cell proliferation and differentiation occurs at each of these three cell stages, and growth factors of the fibroblast growth factor (FGF) and bone morphogenetic protein (BMP) families appear to play particularly important roles in these processes. Analyses of the actions of FGFs and BMPs reveal that negative signaling plays at least as important a role as positive signaling in the regulation of olfactory neurogenesis.
Department of Anatomy and Neurobiology and the Developmental Biology Center, University of California, Irvine, College of Medicine, Irvine, California 92697-1275, USA. alcalof@uci.edu
Anne L
AL
Calof
Alexandre
A
Bonnin
Candice
C
Crocker
Shimako
S
Kawauchi
Richard C
RC
Murray
Jianyong
J
Shou
Hsiao-Huei
HH
Wu
D000818:Animals; D002478:Cells, Cultured; D066298:In Vitro Techniques; D051379:Mice; D009831:Olfactory Mucosa / Q000166:cytology*; D018034:Olfactory Receptor Neurons / Q000166:cytology*; D013234:Stem Cells / Q000502:physiology*