Sgs-4, salivary gland secretion protein 4, Sgs
Low-frequency RNA-Seq exon junction(s) not annotated.
Supported by strand-specific RNA-Seq data.
Gene model reviewed during 5.46
Gene model reviewed during 6.02
There is only one protein coding transcript and one polypeptide associated with this gene
Glycosylation deduced from aberrant migration in acrylamide gels and PAS-staining.
Click to get a list of regulatory features (enhancers, TFBS, etc.) and gene disruptions (point mutations, indels, etc.) within or overlapping Dmel\Sgs4 using the Feature Mapper tool.
GBrowse - Visual display of RNA-Seq signalsView Dmel\Sgs4 in GBrowse 2
Please Note This section lists cDNAs and ESTs that fall within the genomic extent of the gene model, which may include cDNAs and ESTs of genes within introns, or of overlapping genes. Please see GBrowse for alignment of the cDNAs and ESTs to the gene model.
For each fully sequenced cDNA the DGRC maintains various forms of the cDNA (e.g tagged or untagged) in several different host vectors for subsequent cloning and expression in Drosophila and Drosophila cell lines.
The EcR product binds to two sites, element I and element II, in the regulatory region of Sgs4. Element II appears to be of no importance for the expression of Sgs4 while element I is an ecdysone response element necessary, but not sufficient, for Sgs4 induction. Close to elements I and II lie two binding sites for the Sebp3 product. One of these sites is necessary but not sufficient for Sgs4 expression. This hormone response unit also contains binding sites for the fkh product, which coincide with binding sites for Broad Complex products.
Cis-acting sequences required for dosage compensation are located within 840bp upstream of the gene. Germline transformation studies and a comparison of sequences from several dosage compensation genes reveal sequences within the coding region and/or downstream of the gene also play a role in dosage compensation.
An investigation of the relationship between transcription, puffing and hormone regulation of intermoult puff was analysed using ecd1 mutant embryos: Sgs4 expression is severely reduced by shifting ecd1 embryos to the restrictive temperature, 30oC. Normal sized 3C11-12 puff can be formed in conditions in which Sgs4 transcription is severely reduced.
Sgs4 encodes a salivary-gland glue protein. One of a group of seven genes encoding proteins that are components of the secretion produced by the larval salivary glands during the third instar for the purpose of attaching the larva to the substrate preparative to pupariation.
Sgs3, Sgs4 and Sgs5 transcript levels were very low in hemizygous brrbp-1 larvae and pupae.
Adh reporter gene constructs demonstrate Sgs4 is expressed throughout development in the proventriculus and salivary glands. This expression pattern differs form other glue genes and is unique to Sgs4.
The region of Sgs4 needed for developmentally regulated puffing is defined as a 2.5kb 5' upstream fragment. Puff formation requires only the 840bp promoter region, formation of cytologically visible puff depends on the strength of the promoter. Puff formation therefore depends on a cis-acting element which functions through interaction with trans-acting factors.
Germline transformation studies demonstrate that most sequences required for normal Sgs4 expression lie in a 1.9kb region.
Cessation of Sgs4 transcription and puff regression are ecdysterone-dependent.
Initiation of transcription of Sgs4, but not of intermolt-puff formation seems to depend on the presence of suitable levels of ecdysterone in early third instar larvae.
A complex of five tissue-specific DNAase-hypersensitive sites is present 5' to Sgs4 in chromatin from third instar salivary glands.
Synthesis of the glue proteins begins about 106 h after egg deposition and ceases abruptly within a few minutes after the glue is released 14 h later.