Abstract
In female mammals, one of the two X chromosomes in each and every embryonic cell is randomly inactivated during embryogenesis, leaving only one active X chromosome per cell and thereby maintaining dosage parity with males (1). This natural phenomenon, known as X inactivation or lyonization, provides an ideal nonsurgical method of producing mosaicism among otherwise identical cells of the embryo. We have created a line of mice (H253) by pronuclear injection of a DNA fragment containing the lacZ reporter gene under the control of an ubiquitously active promoter (HMG CoA reductase; see ref. 2). Breeding and chromosome hybridization experiments (FISH) with line H253 confirmed that the lacZ gene is inserted into the X-chromosome (3,4). Male members of this line express the X-linked lacZ gene in all cells of the embryo, including the developing nervous system (5). Ubiquitous expression of the lacZ gene produces a nuclear-localized β-gal protein, which, after histochemical reaction with X-gal substrate, is visualized as a blue reaction product visible in the cell nuclei in whole-mount embryos, organs, or tissue sections. In hemizygous females, only one of the two Xs carry the lacZ transgene and this lacZ-bearing chromosome will be randomly turned off in approx 50% of cells (3). The marking process is indelible and heritable (Fig. 1A). The lacZ is integrated in the genome and every time a cell divides, the lacZ gene and either its active or inactive status is passed onto its progeny, forming a marked clone. The initial process of random inactivation occurs early in embryogenesis and is virtually completed by 9.5 d of gestation (E9.5) before organogenesis commences for most tissues.
This is a preview of subscription content, log in via an institution.
Buying options
Tax calculation will be finalised at checkout
Purchases are for personal use only
Learn about institutional subscriptionsReferences
Lyon, M. (1961) Gene action in the X-chromosome of the mouse (Mus musculus L.). Nat. London 190, 372–373.
Tam, P. P. L. and Tan, S.-S. (1992) The somitogenetic potential of cells in the primitive streak and the tail bud of the organogenesis-stage mouse embryo. Development 115, 703–715.
Tan, S.-S., Williams, E. A., and Tam, P. P. L. (1993) X-chromosome inactivation occurs at different times in different tissues of the post-implantation mouse embryo. Nat. Genet. 3, 170–174.
Tan, S.-S., Faulkner-Jones, B. E., Breen, S. J., Walsh, M., Bertram, J. F., and Reese, B. E. (1995) Cell dispersion patterns in different cortical regions studied with an X-inactivated transgenic marker. Development 121, 1029–1039.
Tan, S.-S. and Breen, S. J. (1993) Radial mosaicism and tangential dispersion both contribute to mouse neocortex development. Nature 362, 638–640.
Beddington, R., Morgernstern, J., Land, H., and Hogan, A. (1989) An in situ transgenic enzyme marker for the midgestation mouse embryo and the visualisation of inner cell mass clones during early organogenesis. Development 106, 37–46.
Reese, B. E., Harvey, A. R., and Tan, S.-S. (1995) Radial and tangential dispersion patterns in the mouse retina are cell-class specific. Proc. Natl. Acad. Sci. USA 92, 2494–2498.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2000 Humana Press Inc., Totowa, NJ
About this protocol
Cite this protocol
Tan, SS., Godinho, L., Tam, P.P.L. (2000). Cell Lineage Analysis. In: Walker, J.M., Tuan, R.S., Lo, C.W. (eds) Developmental Biology Protocols. Methods in Molecular Biology™, vol 135. Humana Press. https://doi.org/10.1385/1-59259-685-1:289
Download citation
DOI: https://doi.org/10.1385/1-59259-685-1:289
Publisher Name: Humana Press
Print ISBN: 978-0-89603-852-3
Online ISBN: 978-1-59259-685-0
eBook Packages: Springer Protocols