Disease relevance of sna

• Simultaneous expression of inscuteable and string in the snail family deletion mutant efficiently restores Prospero expression in ganglion mother cells, demonstrating that the two genes are key targets of Snail in neuroblasts [1].

High impact information on sna

• Effective inhibition of mitosis in the cells of the ventral furrow depends on the transcription factor Snail that triggers the ventral cell shape changes [2].
• To initiate the differentiation of the mesoderm in Drosophila, multiple zygotic genes such as twist (twi) and snail (sna), which encode a basic-helix-loop-helix and a zinc finger transcription factor, respectively, are required [3].
• Krüppel (Kr) and snail (sna), two zinc finger repressors, are essential for segmentation and for the establishment of the mesoderm/neuroectoderm boundary, respectively [4].
• The Drosophila scratch (scrt) gene is expressed in most or all neuronal precursor cells and encodes a predicted zinc finger transcription factor closely related to the product of the mesoderm determination gene snail (sna) [5].
• Repression does not depend on proximity of sna-binding sites to the transcription initiation site. sna is not a dedicated repressor but, instead, appears to block disparate activators [6].

Biological context of sna

• Three of the genes, sna, twi, and trh, are known to encode transcription factors and are therefore likely to be part of the network of genes that dictate the malpighian tubule pattern of gene expression [7].
• We discuss the implications of the striking organizational similarities of the dpn, scrt, and sna pan-neural enhancers [8].
• Together with other regulatory molecules including Wnt and BMP, the Snail pathways specify cell fate and reorganize cellular machineries to coordinate morphological changes and cell movements during gastrulation [9].
• Due to the differential response of target genes, one of the mutant alleles, V2, that has reduced Snail function showed an intermediate phenotype [10].
• We show that the Snail family of proteins control central nervous system development by regulating genes involved in asymmetry and cell division of neuroblasts [1].

Anatomical context of sna

• Expression is blocked in ventral regions (the presumptive mesoderm) by snail (sna), which is also a direct target of the dl morphogen [11].
• In the posterior part of the blastoderm, hkb represses the expression of sna in the endodermal primordium (which we suggest to be adjacent to the mesodermal primordium) [12].
• The Notch(IC) stripe induces ectopic expression of sim in the neurogenic ectoderm where there are low levels of the Dorsal gradient. sim is not activated in the ventral mesoderm, due to inhibition by the localized zinc-finger Snail repressor, which is selectively expressed in the ventral mesoderm [13].
• Expression of sna is transient and is observed in tissues derived from all three germ layers [14].
• Starting at germband elongation, a second phase of sna expression appears to be initiated, characterized by a highly dynamic accumulation of transcripts in the developing central and peripheral nervous systems [14].

Physical interactions of sna

• It has been shown that peptides identical to the CtBP binding site in CtIP and at the N terminus of Snail form a series of beta-turns similar to those seen in AdE1A [15].

Regulatory relationships of sna

• Additional studies suggest that the Snail repressor can also stimulate Notch signaling [13].
• The Snail protein family regulates neuroblast expression of inscuteable and string, genes involved in asymmetry and cell division in Drosophila [1].
• We present evidence that dl and twi directly activate sna expression [16].

Other interactions of sna

• Two zygotic genes, snail (sna) and twist (twi), are required for mesoderm development, which begins with the formation of the ventral furrow [12].
• Different patterns of snail (sna) and decapentaplegic (dpp) expression help define the limits of inductive interactions between the mesoderm and dorsal ectoderm after gastrulation [17].
• These studies indicate that Kr and sna function as short-range repressors, which can mediate either quenching or direct repression of the transcription complex, depending on the location of repressor sites [4].
• The Snail repressor positions Notch signaling in the Drosophila embryo [13].
• These results suggest that the Snail family of proteins control both asymmetry and cell division of neuroblasts by activating, probably indirectly, the expression of inscuteable and string [1].

References