The myogenic regulatory gene Mef2 is a direct target for transcriptional activation by Twist during Drosophila myogenesis.

MEF2 is a MADS-box transcription factor required for muscle development in Drosophila. Here, we show that the bHLH transcription factor Twist directly regulates Mef2 expression in adult somatic muscle precursor cells via a 175-bp enhancer located 2245 bp upstream of the transcriptional start site. Within this element, a single evolutionarily conserved E box is essential for enhancer activity. Twist protein can bind to this E box to activate Mef2 transcription, and ectopic expression of twist results in ectopic activation of the wild-type 175-bp enhancer. By use of a temperature-sensitive mutant of twist, we show that activation of Mef2 transcription via this enhancer by Twist is required for normal adult muscle development, and reduction in Twist function results in phenotypes similar to those observed previously in Mef2 mutant adults. The 175-bp enhancer is also active in the embryonic mesoderm, indicating that this enhancer functions at multiple times during development, and its function is dependent on the same conserved E box. In embryos, a reduction in Twist function also strongly reduced Mef2 expression. These findings define a novel transcriptional pathway required for skeletal muscle development and identify Twist as an essential and direct regulator of Mef2 expression in the somatic mesoderm.

[1]  O. H. Lowry,et al.  Protein measurement with the Folin phenol reagent. , 1951, The Journal of biological chemistry.

[2]  I. Deàk.  Mutations of Drosophila melanogaster that affect muscles. , 1977, Journal of embryology and experimental morphology.

[3]  G. Rubin,et al.  Genetic transformation of Drosophila with transposable element vectors. , 1982, Science.

[4]  N. Patel,et al.  Characterization and cloning of fasciclin III: A glycoprotein expressed on a subset of neurons and axon pathways in Drosophila , 1987, Cell.

[5]  B. Thisse,et al.  The twist gene: isolation of a Drosophila zygotic gene necessary for the establishment of dorsoventral pattern. , 1987, Nucleic acids research.

[6]  W. Engels,et al.  A stable genomic source of P element transposase in Drosophila melanogaster. , 1988, Genetics.

[7]  Y. Jan,et al.  Interactions between heterologous helix-loop-helix proteins generate complexes that bind specifically to a common DNA sequence , 1989, Cell.

[8]  Y. Jan,et al.  Patterns of expression of cut, a protein required for external sensory organ development in wild-type and cut mutant Drosophila embryos. , 1990, Genes & development.

[9]  G. Lyons,et al.  Developmental regulation of myosin gene expression in mouse cardiac muscle , 1990, The Journal of cell biology.

[10]  M. Bate,et al.  Expression of a MyoD family member prefigures muscle pattern in Drosophila embryos. , 1990, Genes & development.

[11]  Gerald M. Rubin,et al.  The embryonic expression patterns of zfh-1 and zfh-2, two Drosophila genes encoding novel zinc-finger homeodomain proteins , 1991, Mechanisms of Development.

[12]  M. Bate,et al.  Development of the indirect flight muscles of Drosophila. , 1991, Development.

[13]  M. Leptin.  twist and snail as positive and negative regulators during Drosophila mesoderm development. , 1991, Genes & development.

[14]  M. Bate,et al.  The development of adult abdominal muscles in Drosophila: myoblasts express twist and are associated with nerves. , 1991, Development.

[15]  M. Frasch,et al.  The Drosophila homologue of vertebrate myogenic-determination genes encodes a transiently expressed nuclear protein marking primary myogenic cells. , 1991, Proceedings of the National Academy of Sciences of the United States of America.

[16]  C. Doe,et al.  The prospero gene encodes a divergent homeodomain protein that controls neuronal identity in Drosophila. , 1991, Development (Cambridge, England). Supplement.

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

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

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

[20]  R. Horton,et al.  In Vitro Recombination and Mutagenesis of DNA : SOEing Together Tailor-Made Genes. , 1993, Methods in molecular biology.

[21]  K. Saigo,et al.  Distinct expression of two Drosophila homologs of fibroblast growth factor receptors in imaginai discs , 1993, FEBS letters.

[22]  N. Perrimon,et al.  Targeted gene expression as a means of altering cell fates and generating dominant phenotypes. , 1993, Development.

[23]  S. Higashijima,et al.  Two FGF-receptor homologues of Drosophila: one is expressed in mesodermal primordium in early embryos. , 1993, Development.

[24]  R. Cripps,et al.  Molecular genetic analysis of muscle development, structure, and function in Drosophila. , 1993, International review of cytology.

[25]  M. Bate,et al.  The development of Drosophila melanogaster , 1993 .

[26]  E. Bier,et al.  Double-label in situ hybridization using biotin and digoxigenin-tagged RNA probes. , 1994, BioTechniques.

[27]  Hanh T. Nguyen,et al.  D-mef2: a Drosophila mesoderm-specific MADS box-containing gene with a biphasic expression profile during embryogenesis. , 1994, Proceedings of the National Academy of Sciences of the United States of America.

[28]  R. Schulz,et al.  D-MEF2: a MADS box transcription factor expressed in differentiating mesoderm and muscle cell lineages during Drosophila embryogenesis. , 1994, Proceedings of the National Academy of Sciences of the United States of America.

[29]  E. Füchtbauer,et al.  M-twist is an inhibitor of muscle differentiation. , 1994, Developmental biology.

[30]  G. Lyons,et al.  Mef2 gene expression marks the cardiac and skeletal muscle lineages during mouse embryogenesis. , 1994, Development.

[31]  R A Schulz,et al.  Requirement of MADS domain transcription factor D-MEF2 for muscle formation in Drosophila , 1995, Science.

[32]  M. Taylor,et al.  Drosophila MEF2 is regulated by twist and is expressed in both the primordia and differentiated cells of the embryonic somatic, visceral and heart musculature , 1995, Mechanisms of Development.

[33]  N H Brown,et al.  Anterior-posterior subdivision and the diversification of the mesoderm in Drosophila. , 1995, Development.

[34]  R. Schulz,et al.  A series of mutations in the D-MEF2 transcription factor reveal multiple functions in larval and adult myogenesis in Drosophila. , 1995, Developmental biology.

[35]  Hanh T. Nguyen,et al.  Drosophila MEF2, a transcription factor that is essential for myogenesis. , 1995, Genes & development.

[36]  A. Lassar,et al.  Inhibition of Myogenic bHLH and MEF2 Transcription Factors by the bHLH Protein Twist , 1996, Science.

[37]  E. Olson,et al.  Defining the regulatory networks for muscle development. , 1996, Current opinion in genetics & development.

[38]  R. Schulz,et al.  Expression of the D-MEF2 transcription in the Drosophila brain suggests a role in neuronal cell differentiation. , 1996, Oncogene.

[39]  M. Bate,et al.  twist: A Myogenic Switch in Drosophila , 1996, Science.

[40]  R A Schulz,et al.  D‐mef2 is a target for Tinman activation during Drosophila heart development , 1997, The EMBO journal.

[41]  R. Schulz,et al.  Twist-mediated Activation of the NK-4 Homeobox Gene in the Visceral Mesoderm of Drosophila Requires Two Distinct Clusters of E-box Regulatory Elements* , 1997, The Journal of Biological Chemistry.

[42]  C. Bucana,et al.  Control of mouse cardiac morphogenesis and myogenesis by transcription factor MEF2C. , 1997, Science.

[43]  A. Courey,et al.  A direct contact between the dorsal rel homology domain and Twist may mediate transcriptional synergy , 1997, Molecular and cellular biology.