TY - JOUR
T1 - Temporal regulation of single-minded target genes in the ventral midline of the Drosophila central nervous system
AU - Hong, Joung Woo
AU - Park, Kye Won
AU - Levine, Michael S.
N1 - Funding Information:
We thank Robert Zinzen at the European Molecular Biology Laboratory, Mathew Ronshaugen at the University of Manchester, and Jessica Cande at Institut de Biologie du Développement de Marseille Luminy for helpful discussions; Frédéric Biemar at the Temple University for sharing materials and unpublished results; and Benny Shilo at the Weismann Institute of Science for the rho vn double mutant fly. This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology ( 2010-0002792 and 2012R1A1A2038502 ).
PY - 2013/8/15
Y1 - 2013/8/15
N2 - Differentiation of a specific organ or tissue requires sequential activation of regulatory genes. However, little is known about how serial gene expression is temporally regulated. Here, we present evidence that differential expression of single-minded (sim) target genes can be attributed, in part, to the number of Sim and Tango (Tgo) heterodimer binding sites within their enhancer regions. The Sim, termed a master regulator, directs ventral midline differentiation of Drosophila central nervous system (CNS). According to data on the onset timing of ventral midline gene expression, sim target genes are classified into at least 2 groups (early and late). The sim and rhomboid (rho) genes are activated during early midline differentiation whereas orthodenticle (otd), CG10249, and slit (sli) genes undergo activation during later stages of midline differentiation. Germline transformation and in situ hybridization with transgenic embryos demonstrate that enhancers activating sim and rho expression contain 4 Sim-Tgo binding sites whereas only 1 Sim-Tgo binding site is found in an enhancer of sli. A mutagenized version of the rho enhancer lacking either 1, 2, or 3 Sim-Tgo binding sites mediated progressively more delayed expression of a lacZ reporter gene in the ventral midline. In contrast, a modified sli enhancer displayed progressively earlier onset of lacZ expression when 1, 2, or 3 more Sim-Tgo binding sites were added. Taken together, these results suggest that the number of Sim-Tgo-binding sites is decisive in determining the timing of gene expression in the developing ventral midline. We also discuss a combinatorial model accounting for the sequential expression of sim target genes.
AB - Differentiation of a specific organ or tissue requires sequential activation of regulatory genes. However, little is known about how serial gene expression is temporally regulated. Here, we present evidence that differential expression of single-minded (sim) target genes can be attributed, in part, to the number of Sim and Tango (Tgo) heterodimer binding sites within their enhancer regions. The Sim, termed a master regulator, directs ventral midline differentiation of Drosophila central nervous system (CNS). According to data on the onset timing of ventral midline gene expression, sim target genes are classified into at least 2 groups (early and late). The sim and rhomboid (rho) genes are activated during early midline differentiation whereas orthodenticle (otd), CG10249, and slit (sli) genes undergo activation during later stages of midline differentiation. Germline transformation and in situ hybridization with transgenic embryos demonstrate that enhancers activating sim and rho expression contain 4 Sim-Tgo binding sites whereas only 1 Sim-Tgo binding site is found in an enhancer of sli. A mutagenized version of the rho enhancer lacking either 1, 2, or 3 Sim-Tgo binding sites mediated progressively more delayed expression of a lacZ reporter gene in the ventral midline. In contrast, a modified sli enhancer displayed progressively earlier onset of lacZ expression when 1, 2, or 3 more Sim-Tgo binding sites were added. Taken together, these results suggest that the number of Sim-Tgo-binding sites is decisive in determining the timing of gene expression in the developing ventral midline. We also discuss a combinatorial model accounting for the sequential expression of sim target genes.
KW - Drosophila
KW - Embryo
KW - Single-minded
KW - Temporal regulation
KW - Ventral midline
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U2 - 10.1016/j.ydbio.2013.05.015
DO - 10.1016/j.ydbio.2013.05.015
M3 - Article
C2 - 23701883
AN - SCOPUS:84879889837
SN - 0012-1606
VL - 380
SP - 335
EP - 343
JO - Developmental biology
JF - Developmental biology
IS - 2
ER -