The Wnt and Delta-Notch signalling pathways interact to direct pair-rule gene expression via caudal during segment addition in the spider Parasteatoda tepidariorum.
In short-germ arthropods, posterior segments are added sequentially from a segment addition zone (SAZ) during embryogenesis. Studies in spiders such as Parasteatoda tepidariorum have provided insights into the gene regulatory network (GRN) underlying segment addition, and revealed that Wnt8 is required for dynamic Delta (Dl) expression associated with the formation of new segments. However, it remains unclear how these pathways interact during SAZ formation and segment addition. Here, we show that Delta-Notch signalling is required for Wnt8 expression in posterior SAZ cells, but represses the expression of this Wnt gene in anterior SAZ cells. We also found that these two signalling pathways are required for the expression of the spider orthologues of even-skipped (eve) and runt-1 (run-1), at least in part via caudal (cad). Moreover, it appears that dynamic expression of eve in this spider does not require a feedback loop with run-1, as is found in the pair-rule circuit of the beetle Tribolium Taken together, our results suggest that the development of posterior segments in Parasteatoda is directed by dynamic interactions between Wnt8 and Delta-Notch signalling that are read out by cad, which is necessary but probably not sufficient to regulate the expression of eve and run-1 Our study therefore provides new insights towards better understanding the evolution and developmental regulation of segmentation in other arthropods, including insects.
Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, UK.
Anna
A
Schönauer
Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, UK.
Christian L B
CL
Paese
Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, UK.
Maarten
M
Hilbrant
Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, UK.
Daniel J
DJ
Leite
Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, UK.
Evelyn E
EE
Schwager
Laboratório Integrado de Ciências Morfofuncionais, Universidade Federal do Rio de Janeiro, UFRJ/NUPEM, Campus Macaé, 27910-970 Rio de Janeiro, Brazil.
Natália Martins
NM
Feitosa
Department of Genetics, Friedrich-Schiller-University Jena, Philosophenweg 12, Jena 07743, Germany.
Cornelius
C
Eibner
Department of Genetics, Friedrich-Schiller-University Jena, Philosophenweg 12, Jena 07743, Germany.
Wim G M
WG
Damen
Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, UK amcgregor@brookes.ac.uk.
Alistair P
0000-0002-2908-2420
AP
McGregor
D000818:Animals; D019521:Body Patterning / Q000235:genetics*; D047108:Embryonic Development / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D019476:Insect Proteins / Q000378:metabolism*; D008954:Models, Biological; D011485:Protein Binding / Q000235:genetics; D034622:RNA Interference; D051880:Receptors, Notch / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics; D013112:Spiders / Q000196:embryology* / Q000235:genetics*; D051153:Wnt Proteins / Q000378:metabolism*
D019476:Insect Proteins; D051880:Receptors, Notch; D051153:Wnt Proteins
Delta-Notch signalling; Segmentation; Spiders; Wnt signalling; caudal; even-skipped