Closely related transcripts encoded by the neurogenic gene complex enhancer of split of Drosophila melanogaster.

Abstract

Genetic evidence suggests that E(spl), one of the neurogenic loci of Drosophila, is a gene complex comprising an as yet incompletely established number of transcription units. In order to correlate the various transcription units with E(spl) functions, wild‐type flies were transformed with genomic DNA encoding the transcription unit m8 from the mutant E(spl)D, which was known to be altered in embryos carrying this mutant allele. Transformants show the same dominant enhancement of the spl phenotype as E(spl)D itself. Since m8 has a virtually identical pattern of expression as m4, m5 and m7, we have determined the sequence of these four transcripts. The deduced protein products of m5, m7 and m8 exhibit extensive sequence homology with each other. All three encode a sequence similar to one of the conserved domains of representatives of the vertebrate myc gene family which is also present in the deduced protein sequences of the Drosophila achaete‐scute gene complex. Sequence analysis of the m8 transcription unit in the E(spl)D mutation revealed several DNA lesions. One of the lesions is a deletion in the region upstream of the transcription start site. Another lesion is a deletion in the coding region that leads to a shorter protein which, in addition, differs in its carboxy‐terminal end from the wild‐type protein by the presence of nine amino acids.

Drosophila melanogaster Casein Kinase II Interacts with and Phosphorylates the Basic Helix-Loop-Helix Proteins m5, m7, and m8 Derived from the Enhancer of split Complex

“…This cDNA, which does not contain any in-frame stop codons 5Ј to the initiation codon, is identical to base pairs 172-1068 of a 4.4-kilobase genomic clone (Fig. 1B) that encodes the m7 and m8 transcription units, each on a single uninterrupted exon (55). The absence of a poly(A) tail in clone DmA51, combined with the presence of a single poly(A) addition signal in the corresponding gene at position 1250 (Fig.…”

Id proteins in cell cycle control and cellular senescence

“…Dimerization is essential for DNA binding and transcriptional activity in vivo (Lassar et al, 1991;Massari and Murre, 2000) and in general, class B bHLH proteins form heterodimers with the class A bHLH proteins with few exception, although the latter can also operate as homodimers (Shen and Kadesch, 1995). The basic region of each protein is required for binding to DNA, commonly to a region that includes a speci®c sequence motif known as the E-box (CANNTG) (Ephrussi et al, 1985;Kiledjian et al, 1988;Lassar et al, 1989) or the related N-box (CACNAG) (Klambt et al, 1989;Tietze et al, 1992).…”

The WRPW Motif of the Hairy-Related Basic Helix-Loop-Helix Repressor Proteins Acts as a 4-Amino-Acid Transcription Repression and Protein-Protein Interaction Domain

“…The activator proteins, such as MyoD or the proteins of the Achaete-Scute complex, promote differentiation by binding to class A binding sites and activating transcription (21,50,52,53,56,77,81). The repressor bHLH proteins are Hairy-related proteins such as Hairy, the proteins of the Enhancer of Split [E(spl)] complex, and the homologous mammalian Hes proteins (2,19,23,32,41,43,56,61,62,70,71). These proteins antagonize the activator proteins and prevent differentiation by binding to specific class B or C sites and repressing transcription (2,32,54,56,70,73,75).…”

“…Heterodimers between Daughterless and Achaete-Scute proteins bind and activate the transcription of target genes such as achaete (50,76,77). The repressors are Hairy-related proteins, such as Hairy or the proteins of the E(spl) complex (19,41,43,61). The repressors act to prevent neuronal development at two levels.…”