title: Maintenance of motor neuron progenitors in Xenopus requires a novel localized cyclin.
abstract: The ventral spinal cord contains a pool of motor neuron progenitors (pMNs), which sequentially generate motor neurons and oligodendrocytes in the embryo. The mechanisms responsible for the maintenance of pMNs are not clearly understood. We have identified a novel cyclin, cyclin Dx (ccndx), which is specifically expressed in pMNs in Xenopus. Here, we show that inhibition of ccndx causes paralysis in embryos. Furthermore, we show that maintenance of pMNs requires ccndx function. In addition, inhibition of ccndx results in the specific loss of differentiated motor neurons. However, the expression of interneuron or sensory neuron markers is unaffected in these embryos, suggesting that the role of ccndx is specifically to maintain pMNs. Thus, we have identified, for the first time, a tissue-specific cell-cycle regulator that is essential for the maintenance of a pool of neural progenitors in the vertebrate spinal cord.
authors.affiliation: The Wellcome Trust/Cancer Research UK Gurdon Institute and Department of Zoology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK.
authors.forename: Jun-An
authors.initials: JA
authors.lastname: Chen
authors.forename: Sin-Tak
authors.initials: ST
authors.lastname: Chu
authors.forename: Enrique
authors.initials: E
authors.lastname: Amaya
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D056741:Cyclin D; D016213:Cyclins / Q000235:genetics / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D015151:Immunoblotting; D047468:Immunoprecipitation; D017403:In Situ Hybridization; D008969:Molecular Sequence Data; D009046:Motor Neurons / Q000166:cytology*; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009841:Oligonucleotides; D010243:Paralysis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013116:Spinal Cord / Q000166:cytology*; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism*; D014981:Xenopus / Q000235:genetics* / Q000378:metabolism; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D056741:Cyclin D; D016213:Cyclins; D009419:Nerve Tissue Proteins; D009841:Oligonucleotides; D029867:Xenopus Proteins; C519686:ccndx protein, Xenopus