We have used the H-2Z1 transgene as a marker of somatosensory identity in embryonic cortex transplantation experiments in order to examine to study the role of intrinsic versus extrinsic factors in the regionalization of the neocortex. Our work has contributed to the understanding of the early events responsible for the regionalization of the forebrain, pointing to the critical role of intrinsic cues in this process.
H-2Z1 transgene expression is modified by genetic backgrounds. In a C57/CBA background, expression of the H-2Z1 transgene precisely delineates the somatosensory area and is restricted to a subset of layer IV neurons. In a BALB/c background, H-2Z1 cortical expression is wider and more intense.
H-2Z1 is an enhancer trap transgenic mouse line and as such offers also an opportunity to identify an endogenous gene with a similar expression pattern and therefore to gain further insights into early events responsible for the regionalization of the forebrain in mice as well as in other mammals. We have cloned the integration site of the H-2Z1 transgene and identified several genes in the vicinity of the integration site. All the H-2Z1 flanking genes are expressed in layer IV neurons of the somatosensory area.
Publications related to the H-2Z1 mouse line
Cohen-Tannoudji, M., Babinet, C., and Wassef, M. (1994). Early determination of a mouse somatosensory cortex marker. Nature 368, 460–463.
Cohen-Tannoudji, M., Morello, D. and Babinet C.(1992). Unexpected position-dependent expression of H-2 and beta 2-microglobulin/lacZ transgenes. Mol Reprod Dev 33, 149–159.
Gitton, Y., Cohen-Tannoudji, M., and Wassef, M. (1999a). Role of thalamic axons in the expression of H-2Z1, a mouse somatosensory cortex specific marker. Cereb. Cortex 9, 611–620.
Gitton, Y., Cohen-Tannoudji, M., and Wassef, M. (1999b). Specification of somatosensory area identity in cortical explants. Journal of Neuroscience 19, 4889–4898.
Mallamaci, A., Muzio, L., Chan, C.H., Parnavelas, J., and Boncinelli, E. (2000). Area identity shifts in the early cerebral cortex of Emx2-/- mutant mice. Nat Neurosci 3, 679–686.
Narboux-Nême, N., Goiame, R., Mattei, M.-G., Cohen-Tannoudji, M., and Wassef, M. (2012). Integration of H-2Z1, a Somatosensory Cortex-Expressed Transgene, Interferes with the Expression of the Satb1 and Tbc1d5 Flanking Genes and Affects the Differentiation of a Subset of Cortical Interneurons. Journal of Neuroscience 32, 7287–7300.