QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online May 17, 2004
doi: 10.1242/10.1242/dev.01139

This Article Summary Full Text Full Text (PDF) Supplemental Figures Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Chizhikov, V. V. Articles by Millen, K. J. Search for Related Content PubMed PubMed Citation Articles by Chizhikov, V. V. Articles by Millen, K. J.

Control of roof plate formation by Lmx1a in the developing spinal cord

Department of Human Genetics, University of Chicago, 920 East 58th Street, CLSC 319, Chicago, IL 60637, USA

View larger version (60K): [in a new window]   Fig. 1. Expression of Lmx1a in developing spinal cord. Lmx1a expression (red) alone (A,B,E) or together with Slug (C,F,H), and MafB (D,G,I) (both green) in chick developing spinal cord at the stages indicated. (A) Arrows point to neural folds expressing Lmx1a; n, notochord. (F) Asterisk indicates dorsal midline cells that co-express Lmx1a and Slug. Arrowheads point to Slug-positive/Lmx1a-negative cells delaminating and migrating away from the neural tube.

View larger version (76K): [in a new window]   Fig. 4. Lmx1a withdraws neural progenitors from the cell cycle. GFP-fluorescence (green) in chick neural tubes 48 hours after electroporation (h.a.e.) with Lmx1a-IRES-EGFP (A) or EGFP alone (B). Arrows point to electroporated cells located in the pial layer of the neural tube (A). (C) Schematic representation of the neural tube divided into three layers to quantify distribution of electroporated cells along the medio-lateral axis. (D) Quantification of percent of electroporated cells found in each of these layers. (E-H). BrdU incorporation (red) in chick developing spinal cords 18 h.a.e. (E,F) and 36 h.a.e. (G,H) with Lmx1a-IRES-EGFP. Arrows point to BrdU-positive cells expressing exogenous Lmx1a. Insets show higher magnifications of boxed regions. (I-L). BrdU immunohistochemistry (red) alone (I,K) or together with Lmx1a visualization (green) (J,L) in E10 wild-type (I,J) and dreher (K,L) mouse embryos. BrdU/Lmx1a-double-positive cells (yellow) are indicated by arrowheads (L). Insets show higher magnifications of the dorsal midline regions. Bars equal 40 µm. (M,N) Quantification of proliferation (M) of Lmx1a-positive cells and measurement of Lmx1a-positive area (in arbitrary units) (N) in transverse sections of neural tubes taken from E10.0 wild type and drJ/drJ embryos.

View larger version (86K): [in a new window]   Fig. 6. Lmx1a cell-autonomously inhibits formation of dI1 interneurons. (A-H) Chick spinal cord expressing Lmx1a-IRES-EGFP 48 hours after electroporation. Visualization of expression of LH2A/B (A), Lim 1/2 (C), Islet 1 (E) and Cath1 (G) (all red) alone or together with GFP (green) (B,D,F,H). Insets show higher magnifications of boxed regions. Arrowheads point to yellow cells co-expressing exogenous Lmx1a and Lim1/2 (D) or Islet1 (F). (I-L) Visualization of expression of Math1 (red) alone (I,K) and together with endogenous Lmx1a (green) (J,L) in E10.0 wild-type (I,J) and drJ /drJ embryos (K,L). In drJ /drJ, embryos, numerous Lmx1a/Math1-double-positive cells (yellow) are indicated by arrowheads.

View larger version (78K): [in a new window]   Fig. 2. Exogenous Lmx1a induces ectopic roof plate in the chick developing spinal cord. Expression of MafB (A-E), Msx1/2 (G-K) (both red), Gdf7 (L,M), Bmp4 (N,O), and Wnt1 (P,Q) (all blue) in unelectroporated embryos (A,G,L,N,P) and embryos electroporated with either Lmx1a-IRES-EGFP (B,H,M,O,Q) or EGFP alone (D,E,J,K). All pictures are from stage-24 embryos, 48 hours after electroporation Arrowheads point to ventral boundary of ectopic domains of expression of roof plate markers induced by exogenous Lmx1a. (F) Quantitative analysis of dorsal MafB-positive cells in embryos electroporated with Lmx1a and EGFP alone. (R-U) Expression of MafB (red) and Pax7 (blue) (R,T) or MafB and Pax7 together with GFP (green) (S,U) in intermediate neural plate explants (I.E.), electroporated with Lmx1a-IRES-EGFP (T,U) or EGFP alone (R,S). (V) Quantitative analysis of MafB/Pax7 double-positive cells in intermediate explants electroporated with Lmx1a and EGFP alone.

View larger version (92K): [in a new window]   Fig. 3. Non-cell-autonomous effect of ectopic Lmx1a-generated roof plate on the specification of dorsal interneurons in chick neural tube. Expression of LH2A/B (A-C), Lim1/2 (E-G) and Islet1 (H-L) in neural tubes of unelectroporated embryos (A,E,H) and embryos electroporated with Lmx1a-IRES-EGFP (B,C,F,G,I-L) (all red). All pictures are taken at stage 24, 48 hours after electroporation Arrowheads and arrows point to non-affected and affected neuronal populations, respectively. Insets show higher magnifications of boxed regions. Lim1/2 and Isl1 expressing cells in the ventral half of the neural tube are marked by `V'. (M,N) Visualization of expression of LH2A/B (red) together with GFP (green) in intermediate explants (I.E.) electroporated with Lmx1a-IRES-EGFP (N) or EGFP alone (M). (D,O) Quantitative analysis of LH2-positive cells in embryos (D) or I.E. (O) electroporated with Lmx1a and EGFP alone.

View larger version (66K): [in a new window]   Fig. 5. Lmx1a is not involved in neural crest development. Chick neural tubes electroporated with Lmx1a-IRES-EGFP (A,B,D,E) or EGFP alone (F,G) 18 hours after electroporation (A,B) or 48 hours after electroporation (D-G). (A,B) Visualization of the early neural crest cell marker Slug (red). (D-G) Visualization of migratory neural crest cell by HNK-1 staining (red). Insets show higher magnification of boxed regions. Arrowhead points to yellow cells co-expressing exogenous Lmx1a and Slug. (C) Quantitative analysis of Slug, Sox9 and Ap2-positive cells in chick embryos electroporated with Lmx1a and EGFP alone. Visualization of early neural crest cells by Sox9 (H,I) and Ap2 (J,K) and neurogenic derivatives of dorsal root ganglia revealed by Isl1 staining (M,N) in neural tubes of wild-type (wt) (H,J,M) and dreher (I,K,N) mouse embryos at indicated stages. Quantitative analysis of Sox9 and Ap2 (L), and MitF-positive cells (O) in wild-type and dreher mouse embryos.

View larger version (60K): [in a new window]   Fig. 7. Effect of downregulation of Bmp and Wnt signals on early roof plate development. Chick neural tubes expressing exogenous Noggin (A-E) and dnWnt1 (F-J) 18 hours after electroporation. Visualization of expression of roof plate markers Lmx1a (A,F) and MafB (C,H) (both red), Bmp4 (E,J) (blue) alone or together with GFP (green) (B,D,G,I). Arrowheads point to expression domains affected by overexpression of Noggin.

View larger version (111K): [in a new window]   Fig. 8. Effect of Bmp4 overexpression on Lmx1a expression and roof plate development. (A-D) Chick neural tubes expressing exogenous Bmp4 24 hours after electroporation. Visualization of expression of Lmx1a (A) and MafB (C) (both red) alone or together with GFP (green) (B,D). Arrowheads show the ventral boundary of expanded expression domains of both Lmx1a and MafB in neural tubes electroporated with Bmp4. (E-L) Wild-type (wt exp) (E-H) and dreher (dreher exp) (I-L) explants cultured without Bmp4 (E,F,I,J) or with Bmp4 (G,H,K,L). Visualization of expression of Lmx1a (E,G,I,K) and MafB (F,H,J,L).