Molecular mapping of developing dorsal horn-enriched genes by microarray and dorsal/ventral subtractive screening.
The dorsal horn of the spinal cord consists of distinct laminae that serve as a pivotal region for relaying a variety of somatosensory signals such as temperature, pain, and touch. The molecular mechanisms underlying the development of the dorsal horn are poorly understood. To define a molecular map of the dorsal horn circuit, we have profiled dorsal horn-enriched (DHE) gene expression in dorsal spinal cords on embryonic day 15.5 (E15.5) by genome-wide microarray and smart subtractive screening based on polymerase chain reaction (PCR). High-throughput in situ hybridization (ISH) was carried out to validate the expression of 379 genes in the developing dorsal spinal cord. A total of 113 DHE genes were identified, of which 59% show lamina-specific expression patterns. Most lamina-specific genes were expressed across at least two laminae, however. About 32% of all DHE genes are transcription factors, which represent the largest percentage of the group of all DHE functional classifications. Importantly, several individual lamina-specific transcription factors such c-Maf, Rora, and Satb1 are identified for the first time. Epistasis studies revealed several putative effectors of known DHE transcription factors such as Drg11, Tlx3(Rnx), and Lmx1b. These effector genes, including Grp, Trpc3, Pcp4, and Enc1, have been implicated in synaptic transmission, calcium homeostasis, and structural function and thus may have similar roles in the dorsal horn. The identification of a large number of DHE genes, especially those that are lamina specific, lays a foundation for future studies on the molecular machinery that controls the development of the dorsal horn and on functional differences of these distinct laminae in the dorsal spinal cord.
Li
Mei-Zhang
MZ
Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
Wang
Jin-Shan
JS
Jiang
Dao-Jun
DJ
Xiang
Chuan-Xi
CX
Wang
Feng-Yang
FY
Zhang
Kai-Hua
KH
Williams
Philip R
PR
Chen
Zhou-Feng
ZF
D000818:Animals; D000870:Anterior Horn Cells / Q000378:metabolism*; D018076:DNA, Complementary / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D006824:Hybridization, Genetic; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D051379:Mice; D008810:Mice, Inbred C57BL; D008954:Models, Biological; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*; D020671:Posterior Horn Cells / Q000378:metabolism*; D015347:RNA Probes; D013116:Spinal Cord / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
D018076:DNA, Complementary; D015347:RNA Probes; D014157:Transcription Factors