Factors involved in early polarization of the anterior‐posterior axis in the milkweed bug Oncopeltus fasciatus

Abstract

The axes of insect embryos are defined early in the blastoderm stage. Genes involved in this polarization are well known in Drosophila, but less so in other insects, such as the milkweed bug Oncopeltus fasciatus. Using quantitative PCR, we looked at differential expression of several candidate genes for early anterior-posterior patterning and found that none of them are expressed asymmetrically in the early blastoderm. We then used an RNA-Seq approach to identify novel candidate genes that might be involved in early polarization in Oncopeltus. We focused on transcription factors (TFs) as these are likely to be central players in developmental processes. Using both homology and domain based identification approaches, we were unable to find any TF encoding transcripts that are expressed asymmetrically along the anterior-posterior axis at early stages. Using a GO-term analysis of all asymmetrically expressed mRNAs, we found an enrichment of genes relating to mitochondrial function in the posterior at the earliest studied time-point. We also found a gradual enrichment of transcription related activities, giving us a putative time frame for the maternal to zygotic transition. Our dataset provides us with a list of new candidate genes in early development, which can be followed up experimentally.

Growth zone segmentation in the milkweed bug Oncopeltus fasciatus sheds light on the evolution of insect segmentation

“…We present them roughly in the order of their appearance, from posterior to anterior. To facilitate inter-species comparison, we only report on genes that are orthologs of genes involved in the segmentation cascade of Drosophila , realizing that this does not give the full picture, as there may be other genes involved in segmentation in Oncopeltus that do not have such a role in Drosophila [ 18 , 19 ]. Note that we use the terms pair-rule genes and segment-polarity genes as convenient shorthand for orthologs of genes that have a pair-rule / segment-polarity role in Drosophila , and this does not a-priori imply a similar role in Oncopeltus .…”

Shifting roles ofDrosophilapair-rule gene orthologs: segmental expression and function in the milkweed bugOncopeltus fasciatus

“…Two scaffolds could be merged to complete a sequence with a prd domain, homeodomain, and octapeptide motif NHSIDGILG, which matches the canonical Gsb octapeptide motif (Keller et al, 2010). This candidate from merged scaffolds 2098 and 279 was designated as Of-gsb, in agreement with (Ginzburg et al, 2017). Merging two other scaffolds (1714 and 867) containing prd candidate sequences yielded a sequence with a prd box, homeobox, and lacking an octapeptide motif, designated as Of-prd.…”

The boom and bust of the aphid’s essential amino acid metabolism across nymphal development

“…To further determine how bacteriocyte gene expression changes throughout aphid development, two separate lifestage comparisons were conducted ( Table 1 , Supplementary Datasets S2 and S3). First, we carried out a “sequential” gene expression analysis similar to Ginzburg et al (2017) to identify changes in gene expression between two consecutive lifestages. For this comparison, gene expression of the prior lifestage is compared to the subsequent lifestage to understand how gene expression is different between sequential life stages, which is especially important in insect metamorphosis, incomplete or complete, because dramatic physiological and developmental changes may occur between insect molts.…”