HOMEBOX GENES AND NEURONAL DIFFERENTIATION
Principal Investigator: Gabriel O Aisemberg
Abstract: The goal of this proposal is to establish a collaborative research program between laboratories at the Biology Departments of Lehman College (City University of New York), a predominantly minority institution, and of Columbia University, a major research institution in New York City. The main research aim of this project is to study the role of homeobox genes in neuronal differentiations. Homeobox genes of the vertebrate Hox complexes and the insect homeotic complexes (Hox/HOM genes) are expressed within specific anterior-posterior domains of the central nervous system. The expression patterns of Hox genes suggest a combinatorial code whereby different regions of the nervous system are specified by certain combinations of Hox genes. Certain developmental anomalies of the nervous system found in mammals (including humans) can be traced back to Hox genes. These genes code for homeodomain proteins, a family of transcription factors. It is thought that they control the expression of batteries of genes that specify the particular properties of cells. The Hox/HOM genes are conserved in all animals examined thus far. Our knowledge of Hox/HOM gene function at the single-neuron level is presently quite limited. To improve this situation, it is advantageous to have the ability to study the function of these genes in individual, identified neurons whose properties are well known or easy to study. Nine Hox/HOM genes have been cloned and partially characterized in the leech Hirudo medicinalis. These genes are expressed in different but overlapping sets of neurons. Preliminary results in the leech system support the hypothesis that Hox/HOM genes control the establishment of neuronal identities during development. The objective of this proposal is to test this hypothesis in the leech, a system very suitable for the study of the individual features of neurons. This project intends to study whether neurons that express the same Hox/HOM genes share particular characteristics, such as neurotransmitter type, expression of marker molecules, or axonal morphology, and whether the experimental induction of Hox/HOM gene expression can change aspects of the identity of neurons.
Funding Period: 1998-04-15 - 2004-03-31
more information: NIH RePORT
- Segmental and regional differences in neuronal expression of the leech Hox genes Lox1 and Lox2 during embryogenesisRajendra Gharbaran
Department of Biological Sciences, Lehman College of the City University of New York, 250 Bedford Park Blvd, Bronx, NY 10468, USA
Cell Mol Neurobiol 32:1243-53. 2012..Other Laz1-1 cells show more restricted and isolated Lox1 and Lox2 expression patterns. These results suggest a role of Lox1 and/or Lox2 in defining the anteroposterior boundaries of segmentally iterated neurons...
- Identification of leech embryonic neurons that express a Hox gene required for the differentiation of a paired, segment-specific motor neuronRajendra Gharbaran
Department of Biological Sciences, Lehman College of City University of New York, Bronx, 10468, United States
Int J Dev Neurosci 31:105-15. 2013....
- Regional and segmental differences in the embryonic expression of a putative leech Hox gene, Lox2, by central neurons immunoreactive to FMRFamide-like neuropeptidesRajendra Gharbaran
Department of Biological Sciences, Lehman College, The City University of New York, Bronx, NY, 10468, USA
Invert Neurosci 14:51-8. 2014..Our results suggest a role for Lox2 in very early embryonic development (before the formation of the CNS), and in the differentiation of segmentally repeated and region-specific FLI neurons. ..