Towards understanding the molecular basis of cockroach tergal gland morphogenesis. A transcriptomic approach

Bellés, Xavier; Ylla, Guillem

doi:10.1016/j.ibmb.2015.06.008

Cited by 10 publications

(5 citation statements)

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“…7). Within the 12 kb cluster of B. germanica we have found a sequence homologous to “Tigger transposable element derived protein 4” (TIGD4) for which there are expression data, as it appears in tergal gland transcriptomes24. It is worth noting that many copies of TIGD4 are spread in the genome of B. germanica .…”

Section: Resultsmentioning

confidence: 89%

The microRNA toolkit of insects

Ylla

Fromm

Piulachs

et al. 2016

Sci Rep

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Is there a correlation between miRNA diversity and levels of organismic complexity? Exhibiting extraordinary levels of morphological and developmental complexity, insects are the most diverse animal class on earth. Their evolutionary success was in particular shaped by the innovation of holometabolan metamorphosis in endopterygotes. Previously, miRNA evolution had been linked to morphological complexity, but astonishing variation in the currently available miRNA complements of insects made this link unclear. To address this issue, we sequenced the miRNA complement of the hemimetabolan Blattella germanica and reannotated that of two other hemimetabolan species, Locusta migratoria and Acyrthosiphon pisum, and of four holometabolan species, Apis mellifera, Tribolium castaneum, Bombyx mori and Drosophila melanogaster. Our analyses show that the variation of insect miRNAs is an artefact mainly resulting from poor sampling and inaccurate miRNA annotation, and that insects share a conserved microRNA toolkit of 65 families exhibiting very low variation. For example, the evolutionary shift toward a complete metamorphosis was accompanied only by the acquisition of three and the loss of one miRNA families.

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Section: Resultsmentioning

confidence: 89%

The microRNA toolkit of insects

Ylla

Fromm

Piulachs

et al. 2016

Sci Rep

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“…Males also have a tergal gland that produces a mixture of oligosaccharides and lipids upon which females feed prior to copulation (Nojima et al, 1999). This gland, located on the dorsal abdomen under the wings, appears externally as invagination in the 7 th and 8 th tergites, resulting in a complex structure with depressions and holes that lead to the internal glands (Figure 3B) (Ylla and Belles, 2015). Finally, the ovaries, testes, and accessory glands that compose the male and female reproductive systems can be easily distinguished upon dissection (Figure 3C,D).…”

Section: Resultsmentioning

confidence: 99%

Hemimetabolous insects elucidate the origin of sexual development via alternative splicing

Wexler

Delaney

Bellés

et al. 2019

eLife

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Insects are the only known animals in which sexual differentiation is controlled by sex-specific splicing. The doublesex transcription factor produces distinct male and female isoforms, which are both essential for sex-specific development. dsx splicing depends on transformer, which is also alternatively spliced such that functional Tra is only present in females. This pathway has evolved from an ancestral mechanism where dsx was independent of tra and expressed and required only in males. To reconstruct this transition, we examined three basal, hemimetabolous insect orders: Hemiptera, Phthiraptera, and Blattodea. We show that tra and dsx have distinct functions in these insects, reflecting different stages in the changeover from a transcription-based to a splicing-based mode of sexual differentiation. We propose that the canonical insect tra-dsx pathway evolved via merger between expanding dsx function (from males to both sexes) and narrowing tra function (from a general splicing factor to dedicated regulator of dsx).

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“…Males also have a tergal gland that produces a mixture of oligosaccharides and lipids upon which females feed prior to copulation (74). This gland, located on the dorsal abdomen under the wings, appears externally as invagination in the 7 th and 8 th tergites, resulting in a complex structure with depressions and holes that lead to the internal glands (Figure 3B) (75). Finally, the ovaries, testes, and accessory glands that compose the male and female reproductive systems can be easily distinguished upon dissection (Figure 3C, D).…”

Section: Resultsmentioning

confidence: 99%

Hemimetabolous insects elucidate the origin of sexual development via alternative splicing

Wexler

Delaney

Bellés

et al. 2019

Preprint

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25Insects are the only animals in which sexual differentiation is controlled by sex-specific RNA 26 splicing. The doublesex (dsx) transcription factor produces distinct male and female protein 27 isoforms (DsxM and DsxF) under the control of the RNA splicing factor transformer (tra). tra 28 itself is also alternatively spliced so that a functional Tra protein is only present in females; thus, 29 DsxM is produced by default, while DsxF expression requires Tra. The sex-specific Dsx 30 isoforms are essential for both male and female sexual differentiation. This pathway is 31 profoundly different from the molecular mechanisms that control sex-specific development in 32 other animal groups. In animals as different as vertebrates, nematodes, and crustaceans, sexual 33 differentiation involves male-specific transcription of dsx-related transcription factors that are 34 not alternatively spliced and play no role in female sexual development. To understand how the 35 unique splicing-based mode of sexual differentiation found in insects evolved from a more 36 ancestral transcription-based mechanism, we examined dsx and tra expression in three basal, 37 hemimetabolous insect orders. We find that functional Tra protein is limited to females in the 38 kissing bug Rhodnius prolixus (Hemiptera), but is present in both sexes in the louse Pediculus 39 humanus (Phthiraptera) and the cockroach Blattella germanica (Blattodea). Although 40 alternatively spliced dsx isoforms are seen in all these insects, they are sex-specific in the 41 cockroach and the kissing bug but not in the louse. In B. germanica, RNAi experiments show 42 that dsx is necessary for male, but not female, sexual differentiation, while tra controls female 43 development via a dsx-independent pathway. Our results suggest that the distinctive insect 44 mechanism based on the tra-dsx splicing cascade evolved in a gradual, mosaic process: sex-45 specific splicing of dsx predates its role in female sexual differentiation, while the role of tra in 46 regulating dsx splicing and in sexual development more generally predates sex-specific 47 52 53 Sex determination and sexual differentiation evolve on drastically different time scales. Sex 54 determination (that is, the primary signal directing the embryo to develop as male or female) can 55 be either environmental or genetic. Genetic sex determination can in turn be either male-or 56 female-heterogametic (with or without heteromorphic sex chromosomes), mono-or polygenic, or 57 haplo-diploid, among other mechanisms (1-7). Primary sex determination is among the most 58 rapidly evolving developmental processes. In African clawed frogs, medaka, salmon, and other 59 animals, there are many examples of recently evolved sex-determining genes, so that the primary 60 sex determination genes can differ between closely related species (8-13). The signals initiating 61 male or female development can vary even within species, as seen in cichlids, zebrafish, house 62 flies, and Ranid frogs (5,(14)(15)(16)(17)(18). 63In contrast, sex...

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Towards understanding the molecular basis of cockroach tergal gland morphogenesis. A transcriptomic approach

Cited by 10 publications

References 54 publications

The microRNA toolkit of insects

The microRNA toolkit of insects

Hemimetabolous insects elucidate the origin of sexual development via alternative splicing

Hemimetabolous insects elucidate the origin of sexual development via alternative splicing

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