Dlx1, Dlx2, Pax6, Brn3b, and Chx10 homeobox gene expression defines the retinal ganglion and inner nuclear layers of the developing and adult mouse retina.
Distal-less homeobox genes are expressed in the developing forebrain. We assessed Dlx gene expression in the developing and adult mouse retina. Dlx1 and Dlx2 are detected in retinal neuroprogenitors by embryonic day (E) 12.5 (Eisenstat et al. [1999] J. Comp. Neurol. 217-237). At E13.5, the expression of four homeodomain proteins, DLX2, BRN3b, PAX6, and CHX10, define distinct yet overlapping domains in the retinal neuroepithelium. By postnatal day (P) 0, DLX2 is expressed in the neuroblastic layer and the ganglion cell layer (GCL) consisting of ganglion and displaced amacrine cells. DLX1 expression resembles DLX2 to P0 but decreases postnatally. In the adult, DLX2 is localized to ganglion, amacrine, and horizontal cells as determined by coexpression with retinal cell-specific markers. There is coincident expression of DLX2 with gamma-aminobutyric acid (GABA), glutamic acid decarboxylase (GAD)65, and GAD67 in the inner nuclear layer (INL) and GCL. In the adult, DLX2 is coexpressed with BRN3b in ganglion cells; PAX6 in amacrine, horizontal, and ganglion cells; and Chx10 in some bipolar cells. We predict that a combinatorial code of these homeobox genes and others specify retinal cell fate. Our results support a possible role for Dlx1 and Dlx2 in inner retinal development and in the terminal differentiation and/or maintenance of INL interneurons and ganglion cells in the adult. The correlation of DLX2 with GABA expression in the mouse retina closely mirrors the relationship of DLX2 to GABAergic neuronal differentiation in the embryonic forebrain, including neocortex, olfactory bulb and hippocampus, signifying a conservation of function of Dlx genes in the developing central nervous system.
Manitoba Institute of Cell Biology, University of Manitoba, Winnipeg, Manitoba R3E 0V9, Canada.
Jimmy
J
de Melo
Xiangguo
X
Qiu
Guoyan
G
Du
Leah
L
Cristante
David D
DD
Eisenstat
D025042:Amacrine Cells / Q000166:cytology / Q000378:metabolism; D000818:Animals; D002454:Cell Differentiation / Q000235:genetics*; D019070:Cell Lineage / Q000235:genetics; D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism; D005136:Eye Proteins; D005333:Fetus; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D005968:Glutamate Decarboxylase / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D007150:Immunohistochemistry; D007395:Interneurons / Q000166:cytology / Q000378:metabolism; D007527:Isoenzymes / Q000378:metabolism; D051379:Mice; D008813:Mice, Inbred ICR; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; D012333:RNA, Messenger / Q000378:metabolism; D016601:RNA-Binding Proteins; D012097:Repressor Proteins; D012160:Retina / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D012165:Retinal Ganglion Cells / Q000166:cytology / Q000378:metabolism*; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism; D050818:Transcription Factor Brn-3; D050820:Transcription Factor Brn-3B; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins; C088334:Distal-less homeobox proteins; D005136:Eye Proteins; D018398:Homeodomain Proteins; D007527:Isoenzymes; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; C000605732:Pax6 protein, mouse; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D012097:Repressor Proteins; C093661:Tes protein, mouse; D050818:Transcription Factor Brn-3; D050820:Transcription Factor Brn-3B; D014157:Transcription Factors; C088975:Vsx2 protein, mouse; D005680:gamma-Aminobutyric Acid; D005968:Glutamate Decarboxylase; C402565:glutamate decarboxylase 1; C401141:glutamate decarboxylase 2; D004298:Dopamine