Transcriptional repression in the Drosophila embryo.

Transcriptional repression is essential for the conversion of crude maternal gradients into sharp territories of tissue differentiation in the Drosophila embryo. Evidence will be presented suggesting that some of the embryonic repressors function through a short-range 'quenching' mechanism, whereby a repressor works over short distances (ca. 50 b.p.) to block neighbouring activators within a target enhancer. This type of repression can explain how different enhancers work autonomously within complex modular promoters. However, at least one of the repressors operating in the early embryo works through a long-range, or silencing, mechanism. The binding of a silencer to a given enhancer leads to the inactivation of all enhancers within a complex promoter. The analysis of chromatin boundary elements suggest that silencers and enhancers might work through distinct mechanisms. We speculate that silencers constrain the evolution of complex promoters.

[1]  Roger Brent,et al.  Groucho is required for Drosophila neurogenesis, segmentation, and sex determination and interacts directly with hairy-related bHLH proteins , 1994, Cell.

[2]  Jun Ma,et al.  An HMG-like protein that can switch a transcriptional activator to a repressor , 1994, Nature.

[3]  M. Levine,et al.  Short-range repression permits multiple enhancers to function autonomously within a complex promoter. , 1994, Genes & development.

[4]  C. Rushlow,et al.  The Drosophila dorsal morphogen represses the tolloid gene by interacting with a silencer element , 1994, Molecular and cellular biology.

[5]  M. Levine,et al.  Spacing ensures autonomous expression of different stripe enhancers in the even-skipped promoter. , 1993, Development.

[6]  C. Rushlow,et al.  Conversion of a silencer into an enhancer: evidence for a co‐repressor in dorsal‐mediated repression in Drosophila. , 1993, The EMBO journal.

[7]  M. Levine,et al.  Conversion of a dorsal‐dependent silencer into an enhancer: evidence for dorsal corepressors. , 1993, The EMBO journal.

[8]  J. D. Huang,et al.  The interplay between multiple enhancer and silencer elements defines the pattern of decapentaplegic expression. , 1993, Genes & development.

[9]  Michael Levine,et al.  Binding affinities and cooperative interactions with bHLH activators delimit threshold responses to the dorsal gradient morphogen , 1993, Cell.

[10]  M. Levine,et al.  Regulation of even‐skipped stripe 2 in the Drosophila embryo. , 1992, The EMBO journal.

[11]  V. Corces,et al.  DNA position-specific repression of transcription by a Drosophila zinc finger protein. , 1992, Genes & development.

[12]  M. Levine,et al.  The dorsal gradient morphogen regulates stripes of rhomboid expression in the presumptive neuroectoderm of the Drosophila embryo. , 1992, Genes & development.

[13]  M. Levine,et al.  dorsal-twist interactions establish snail expression in the presumptive mesoderm of the Drosophila embryo. , 1992, Genes & development.

[14]  M. Levine,et al.  Individual dorsal morphogen binding sites mediate activation and repression in the Drosophila embryo. , 1992, The EMBO journal.

[15]  D. Lindsley,et al.  The Genome of Drosophila Melanogaster , 1992 .

[16]  Alexander D. Johnson,et al.  Ssn6-Tup1 is a general repressor of transcription in yeast , 1992, Cell.

[17]  C. Nüsslein-Volhard,et al.  The origin of pattern and polarity in the Drosophila embryo , 1992, Cell.

[18]  M. Levine,et al.  Regulation of a segmentation stripe by overlapping activators and repressors in the Drosophila embryo. , 1991, Science.

[19]  D Kosman,et al.  The dorsal morphogen gradient regulates the mesoderm determinant twist in early Drosophila embryos. , 1991, Genes & development.

[20]  J. D. Huang,et al.  Functional analysis of the Drosophila twist promoter reveals a dorsal-binding ventral activator region. , 1991, Genes & development.

[21]  B. Thisse,et al.  Sequence-specific transactivation of the Drosophila twist gene by the dorsal gene product , 1991, Cell.

[22]  M. Levine,et al.  Transcriptional regulation of a pair-rule stripe in Drosophila. , 1991, Genes & development.

[23]  Paul Schedl,et al.  A position-effect assay for boundaries of higher order chromosomal domains , 1991, Cell.

[24]  M. Levine,et al.  The dorsal morphogen is a sequence-specific DNA-binding protein that interacts with a long-range repression element in drosophila , 1991, Cell.

[25]  Y. Jan,et al.  rhomboid, a gene required for dorsoventral axis establishment and peripheral nervous system development in Drosophila melanogaster. , 1990, Genes & development.

[26]  M. Levine,et al.  Transcriptional repression of eukaryotic promoters , 1989, Cell.

[27]  M. Levine,et al.  Spatial regulation of zerknüllt: a dorsal-ventral patterning gene in Drosophila. , 1989, Genes & development.

[28]  Michael Levine,et al.  Sequence-specific DNA-binding activities of the gap proteins encoded by hunchback and Krüppel in Drosophila , 1989, Nature.

[29]  Tom Maniatis,et al.  Early and late periodic patterns of even skipped expression are controlled by distinct regulatory elements that respond to different spatial cues , 1989, Cell.

[30]  M. Levine,et al.  Autoregulatory and gap gene response elements of the even‐skipped promoter of Drosophila. , 1989, The EMBO journal.

[31]  M. Frasch,et al.  Characterization and localization of the even‐skipped protein of Drosophila. , 1987, The EMBO journal.

[32]  P. Ingham,et al.  Isolation, structure, and expression of even-skipped: A second pair-rule gene of Drosophila containing a homeo box , 1986, Cell.

[33]  M. Levine,et al.  Cross-regulatory interactions among pair-rule genes in Drosophila. , 1986, Science.