Chromosomal position mediates spinal cord expression of a dbx1a enhancer.
Dbx homeodomain proteins are important for the production of multiple spinal cord cell types. To examine the regulation of Dbx genes in more detail, we have generated transgenic zebrafish in which fluorescent protein expression is driven by predicted dbx1a enhancers. We identified three areas of sequence conservation upstream of the dbx1a coding sequence and generated fluorescent reporter constructs driven by these predicted enhancer elements and the endogenous dbx1a promoter. In multiple stable insertions of a 3.5-kb enhancer fragment, we observed that there was additional reporter expression in the dorsal spinal cord not normally observed by dbx1a in situ hybridization. In addition, these lines exhibited only transient reporter expression, unlike the endogenous gene. Surprisingly, a single insertion line expressed the reporter in the endogenous pattern, indicating that other local regulatory elements modulate gene expression through the 3.5-kb enhancer.
Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, Utah 84132-3401, USA.
Suzanna L
SL
Gribble
O Brant
OB
Nikolaus
M Scott
MS
Carver
Kazuyuki
K
Hoshijima
Richard I
RI
Dorsky
D000818:Animals; D002875:Chromosomes; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D004742:Enhancer Elements, Genetic / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D017930:Genes, Reporter / Q000235:genetics / Q000502:physiology; D018398:Homeodomain Proteins / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics / Q000502:physiology; D013116:Spinal Cord / Q000196:embryology* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics*; D019076:Transgenes / Q000235:genetics / Q000502:physiology*; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics / Q000378:metabolism; D029961:Zebrafish Proteins / Q000235:genetics*
D018398:Homeodomain Proteins; D014157:Transcription Factors; D029961:Zebrafish Proteins; C490000:dbx1a protein, zebrafish