zen is required for only a brief period of Drosophila development, (2- 4 hours after fertilization) but its effects are found later, especially during germ band extention [Images]. In the absense of zen, germ-band extension is abnormal.
Normally, the amioserosa plays a key role in the elongation process and becomes profusely folded where the posterior tip of the germ band contacts the procephalon, and is driven into the proctodeal cavity by the expanding germ band. The absence of the amnioserosa in zen mutants might cause the germ band to be twisted and thrown into folds during an abortive elongation process (Rushlow C., 1990).
zerknullt is unique among homeo box genes in Drosophila since it is required for the differentiation of the dorsal-ventral pattern, and does not appear to be involved in the process of segmentation.
Upstream Genes |
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| tld | twi | dl | kr | kni | dpp | sna | ||
zerknult |
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| pan | ||||||||
Downstream Genes |
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A GATA family transcription factor is expressed along the embryonic dorsoventral axis in Drosophila melanogaster. Development 119: 1055-65 (1993)
Race: a drosophila homologue of the angiotensin converting enzyme. Mech Dev 51: 157-168 (1995)
Repression of the Drosophila proliferating-cell nuclear antigen gene promoter by zerknullt protein. Mol Cell Biol 11: 4909-17 (1991)
Repression of regulatory factor for Drosophila DNA replication-related gene promoters by zerknullt homeodomain protein. J Biol Chem 269: 2937-42 (1994)
The Drosophila dorsal morphogen represses the tolloid gene by interacting with a silencer element. Mol Cell Biol 14: 713-722 (1994)
Conversion of a silencer into an enhancer: evidence for a co-repressor in dorsal-mediated repression in Drosophila. EMBO J 12: 3193-9 (1993)
An HMG-like protein that can switch a transcriptional activator to a repressor. Nature 371: 175-179 (1994)
The same dorsal binding site mediates both activation and repression in a context-dependent manner. EMBO J 11: 1837-42 (1992)
The control of cell fate along the dorsal-ventral axis of the Drosophila embryo. Development 113: 35-54 (1991)
Long-range repression in the Drosophila embryo. Proc Natl Acad Sci U S A 93: 9309-14 (1996)
Long-range repression in the Drosophila embryo. Proc Natl Acad Sci U S A 93: 9309-14 (1996)
Long-range repression in the Drosophila embryo. Proc Natl Acad Sci U S A 93: 9309-14 (1996)
Long-range repression in the Drosophila embryo. Proc Natl Acad Sci U S A 93: 9309-14 (1996)
Binding sites for transcription factor NTF-1/Elf-1 contribute to the ventral repression of decapentaplegic. Genes Dev 9: 3177-3189 (1995)
The interplay between multiple enhancer and silencer elements defines the pattern of decapentaplegic expression. Genes Dev 7: 694-704 (1993)
Role of the zerknullt gene in dorsal-ventral pattern formation in Drosophila. Adv Genet 27: 277-307 (1990)
Individual dorsal morphogen binding sites mediate activation and repression in the Drosophila embryo. EMBO J 11: 3147-54 (1992)
Role of the zerknullt gene in dorsal-ventral pattern formation in Drosophila. Adv Genet 27: 277-307 (1990)
Cai, H. and Levine, M. (1995). Modulation of enhancer-promoter insulators in the Drosophila embryo. Nature 376: 533-536
Cai, H. N., Arnosti, D. N. and Levine, M. (1996). Long-range repression in the Drosophila embryo. Proc. Natl. Acad. Sci. 93: 9309-14
Chen, H. Z. and Zubay, G. (1989). Two nearby sites bind zen protein independently. Mol. Cell. Biochem. 90: 27-35
Doyle, H. J. Kraut, R. and Levine, M. (1989). Spatial regulation of zerknüllt: a dorsal-ventral patterning gene in Drosophila. Genes Dev. 3: 1518-33
Falciani, F., et al. (1996). Class 3 Hox genes in insects and the origin of zen. Proc. Natl. Acad. Sci. 93: 8479-8484
Hirose, F., Yamaguchi, M. and Matsukage, A. (1994). Repression of regulatory factor for Drosophila DNA replication-related gene promoters by zerknüllt homeodomain protein. J. Biol. Chem. 269: 2937-42
Hirose, F., et al. (1996). Isolation and characterization of cDNA for DREF, a promoter-activating factor for Drosophila DNA replication-related genes. J. Biol. Chem. 271: 3930-3937
Huang, J. D., et al. (1993). The interplay between multiple enhancer and silencer elements defines the pattern of decapentaplegic expression. Genes Dev. 7: 694-704
Huang, J. D., et al. (1995). Binding sites for transcription factor NTF-1/Elf-1 contribute to the ventral repression of decapentaplegic. Genes Dev. 9: 3177-3189
Jiang, J., et al (1992). Individual dorsal morphogen binding sites mediate activation and repression in the Drosophila embryo. EMBO J. 11: 3147-54
Kirov, N., et al. (1993). Conversion of a silencer into an enhancer: evidence for a co-repressor in dorsal-mediated repression in Drosophila. EMBO J. 12: 3193-9
Lehming, N. (1994). An HMG-like protein that can switch a transcriptional activator to a repressor. Nature 371: 175-179
Pan, D. and Courey, A. J. (1992). The same dorsal binding site mediates both activation and repression in a context-dependent manner. EMBO J. 11: 1837-42
Ray,R. P., et al. (1991). The control of cell fate along the dorsal-ventral axis of the Drosophila embryo. Development 113: 35-54
Rusch, J. and Levine, M. (1994). Regulation of the dorsal morphogen by the Toll and torso signaling pathways: a receptor tyrosine kinase selectively masks transcriptional repression. Genes Dev. 8: 1247-1257
Rusch, J. and Levine, M. (1997). Regulation of a dpp target gene in the Drosophila embryo. Development 124: 303-311
Rushlow, C., Doyle, H., Hoey, T. and Levine, M. (1987). Molecular characterization of the zerknüllt region of the Antennapedia gene complex in Drosophila. Genes Dev. 1: 1268-79
Rushlow, C. and Levine, M. (1990). The role of zerknüllt gene in dorsal-ventral pattern formation in Drosophila. Adv. Genetics 27: 277-307
Tatei, K., Cai, H., Ip, T. and Levine, M. (1995). Race: a Drosophila homologue of the angiotensin converting enzyme. Mech. Dev. 51: 157-168
Terol, J., Perez-Alonso, M. and de Frutos, R. (1995). Molecular characterization of the zerknüllt region of the Antennapedia complex of D. subobscura. Chromosoma 103: 613-624
Winick, J., et al. (1993). A GATA family transcription factor is expressed along the embryonic dorso-ventral axis in Drosophila melanogaster . Development 119: 1055-65
Yamaguchi, M., et al. (1991). Repression of the Drosophila proliferating-cell
nuclear antigen gene promoter by zerknüllt protein. Mol Cell Biol.
11: 4909-17
HOM-C
HOX-Pro