Disease relevance of Sgs4

• Another strain, which has multiple 5' lesions, is severely reduced in Sgs-4 expression and in the DNase hypersensitivity of the upstream region [1].

High impact information on Sgs4

• For Sgs-4, the 5' SAR covers 866 bp immediately upstream of the transcript, and in the case of fushi tarazu, the 5' SAR is found on a small fragment 4.8 kb upstream of the start of transcription [2].
• Proximity-dependent enhancement of Sgs-4 gene expression in D. melanogaster [3].
• The Drosophila Sgs-4 gene directs the developmentally regulated production of a glue protein in the salivary glands of mature larvae [4].
• We demonstrate that these binding sites are relevant to the transcriptional activation of Sgs-4 and show that Fork head also binds to the Sgs-4 ecdysone response unit in vivo [5].
• Therefore, induction of Sgs-4 requires binding of both ecdysone receptor and SEBP 3 to a complex hormone response unit, which also contains binding sites for a third factor, SEBP 2 [6].

Biological context of Sgs4

• For Sgs-4, we have previously demonstrated that its strictly tissue and stage-specific expression is the result of combined action of the ecdysone receptor and secretion enhancer binding proteins (SEBPs) [7].
• Sgs-4 upstream sequences, unchanged or recombined with sequences from differently expressed alleles, were fused with Sgs-4 coding and downstream sequences or with the coding sequence of the viral oncogene v-mil [8].
• Naturally occurring mutations of the Sgs-4 promoter region diminish both the level of Sgs-4 expression and the puff size; in null-producers no puff is formed [8].
• The results obtained show that significant nucleotide sequence alterations are accumulated within the Sgs-4 coding and 3' untranslated region of the variant strain, thus suggesting a possible role of these sequences in the Sgs-4 dosage compensation [9].
• Molecular characterization of a Drosophila melanogaster variant strain defective in the Sgs-4 gene dosage compensation [9].

Anatomical context of Sgs4

• The Drosophila melanogaster gene Sgs4 encodes one of the glue polypeptides, sgs-4, synthesized in the larval salivary gland [10].
• Here we demonstrate by germ line transformation of cloned fragments containing Sgs-4 that the sequences between 840 bp 5' and 130 bp 3' to the gene are sufficient for Sgs-4 activity [11].

Associations of Sgs4 with chemical compounds

• The steroid hormone 20-hydroxyecdysone controls both induction and repression of the Drosophila 'intermolt gene' Sgs-4 [6].
• Transcript accumulation of the 3C glue protein gene Sgs-4 was induced in cultured salivary glands of Drosophila third instar larvae by supplementing the culture medium with 20-OH-ecdysone [12].

Other interactions of Sgs4

• FKH and SEBP3 have been shown previously to be involved in the regulation of Sgs-3 and Sgs-4 [13].
• Surprisingly, in the case of the Sgs-4 gene this response also requires a direct contribution of the 20E-receptor complex [14].
• We have transformed Drosophila with a hybrid gene consisting of the sgs-4 promoter sequence and the coding sequence for a variant (LCP-f2) of LCP-2 [15].
• The molecular organization of the dunce gene of Drosophila melanogaster has proved to be particularly complex, with two divergently transcribed genes, Sgs-4 and Pig-1, nested within its 79 kb intron (1) [16].
• Five binding sites have been identified within the intron by DNAase I footprinting and a core consensus sequence has been derived which shares some identity with the consensus binding site of the Z2 protein to the Sgs-4 regulatory region [17].

Analytical, diagnostic and therapeutic context of Sgs4

• The polytene chromosomes of Drosophila strains that differ in the synthesis of the major salivary gland glue protein sgs-4 were examined by indirect immunofluorescence using antisera to several nonhistone chromosomal proteins [18].
• Fine structure restriction endonuclease mapping shows that approximately 45% of this gene consists of tandemly repeated sequences of 21 base pairs that occupy most of its 5' half, indicating that most of the amino-terminal half of the sgs-4 protein consists of tandemly repeated amino acid sequences of seven residues [19].

References