High impact information on her1

• Additional analysis revealed that stripes of her1 expression oscillate within the PSM and that aei/DeltaD signaling is required for this oscillation. aei/DeltaD expression does not oscillate, indicating that the activity of the Notch pathway upstream of her1 may function within the oscillator itself [1].
• Moreover, we found that her1 stripes are expressed in the anlage of consecutive somites, indicating that its expression pattern is not pair-rule [1].
• On the other hand, injection of gadd45beta1 or gadd45beta2 suppressed expression of mesp-a and her1 in anterior PSM and MyoD in paraxial mesoderm [2].
• Using specific morpholino oligonucleotide mediated inhibition and intron probe in situ hybridisation, we find that her7 is required for initiating the expression in the posterior PSM, while her1 is required to propagate the cyclic expression in the intermediate and anterior PSM [3].
• Reporter gene constructs with the her1 upstream sequence driving green fluorescent protein (GFP) expression show that separable regulatory regions can be identified that mediate expression in the posterior versus intermediate and anterior PSM [3].

Biological context of her1

• Combining a decrease of her7 function with reduction of her1 function results in an enhanced phenotype that affects all the anterior segments, indicating that Her functions in the anterior segments are also partially redundant [4].
• Two linked hairy/Enhancer of split-related zebrafish genes, her1 and her7, function together to refine alternating somite boundaries [5].
• This analysis indicates that these oscillations in gene expression are created by a genetic circuit comprised of the notch pathway and the notch target gene her1 [6].

Anatomical context of her1

• A combined loss of the cyclic Her genes her1 and her7 disrupts segmentation of both anterior and posterior paraxial mesoderm, indicating that her genes function redundantly in anterior segmentation [7].
• her1, a zebrafish pair-rule like gene, acts downstream of notch signalling to control somite development [8].

Other interactions of her1

• The oscillator is comprised of genetic circuit involving the Notch signaling pathway and its target genes her1 and her7 [9].
• Activation of notch results in ectopic activation of her1 and her4 [8].
• In the zebrafish, oscillations in the expression of a hairy-related transcription factor, her1 and the notch ligand deltaC precede somite formation [6].
• The her1 stripe, which first appears in the tailbud region, moves in a caudal to rostral direction, and it finally overlaps the most rostral mesp stripe [10].
• her1 and her13.2 are jointly required for somitic border specification along the entire axis of the fish embryo [11].

References