The neuroblast timer gene nubbin exhibits functional redundancy with gap genes to regulate segment identity in Tribolium

Mapping Intimacies ◽

10.1101/2021.04.08.438913 ◽

2021 ◽

Author(s):

Olivia R A Tidswell ◽

Matthew A Benton ◽

Michael E Akam

Keyword(s):

Gene Expression ◽

Regulatory Network ◽

Gene Network ◽

In Situ Hybridisation ◽

Hox Gene ◽

Gap Gene ◽

Gap Genes ◽

Sequential Mode ◽

And Function

In Drosophila, segmentation genes of the gap class form a regulatory network that positions segment boundaries and assigns segment identities. This gene network shows striking parallels with another gene network known as the neuroblast timer series. The neuroblast timer genes hunchback, Krüppel, nubbin, and castor are expressed in temporal sequence in neural stem cells to regulate the fate of their progeny. These same four genes are expressed in corresponding spatial sequence along the Drosophila blastoderm. The first two, hunchback and Krüppel, are canonical gap genes, but nubbin and castor have limited or no roles in Drosophila segmentation. Whether nubbin and castor regulate segmentation in insects with the ancestral, sequential mode of segmentation remains largely unexplored. We have investigated the expression and functions of nubbin and castor during segment patterning in the sequentially-segmenting beetle Tribolium. Using multiplex fluorescent in situ hybridisation, we show that Tc-hunchback, Tc-Krüppel, Tc-nubbin and Tc-castor are expressed sequentially in the segment addition zone of Tribolium, in the same order as they are expressed in Drosophila neuroblasts. Furthermore, simultaneous disruption of multiple genes reveals that Tc-nubbin regulates segment identity, but does so redundantly with two previously described gap/gap-like genes, Tc-giant and Tc-knirps. Knockdown of two or more of these genes results in the formation of up to seven pairs of ectopic legs on abdominal segments. We show that this homeotic transformation is caused by loss of abdominal Hox gene expression, likely due to expanded Tc-Krüppel expression. Our findings support the theory that the neuroblast timer series was co-opted for use in insect segment patterning, and contribute to our growing understanding of the evolution and function of the gap gene network outside of Drosophila.

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The neuroblast timer gene nubbin exhibits functional redundancy with gap genes to regulate segment identity in Tribolium

Development ◽

10.1242/dev.199719 ◽

2021 ◽

Author(s):

Olivia RA Tidswell ◽

Matthew A. Benton ◽

Michael Akam

Keyword(s):

Gene Expression ◽

Stem Cells ◽

Neural Stem Cells ◽

Crucial Role ◽

Gene Network ◽

Homeotic Transformation ◽

Hox Gene ◽

Gap Gene ◽

Gap Genes ◽

And Function

The neuroblast timer genes hunchback, Krüppel, nubbin, and castor are expressed in temporal sequence in neural stem cells, and in corresponding spatial sequence along the Drosophila blastoderm. As canonical gap genes, hunchback and Krüppel play a crucial role in insect segmentation, but the roles of nubbin and castor in this process remain ambiguous. We have investigated the expression and functions of nubbin and castor during segmentation in the beetle Tribolium. We show that Tc-hunchback, Tc-Krüppel, Tc-nubbin and Tc-castor are expressed sequentially in the segment addition zone, and that Tc-nubbin regulates segment identity redundantly with two previously described gap/gap-like genes, Tc-giant and Tc-knirps. Simultaneous knockdown of Tc-nubbin, Tc-giant and Tc-knirps results in the formation of ectopic legs on abdominal segments. This homeotic transformation is caused by loss of abdominal Hox gene expression, likely due to expanded Tc-Krüppel expression. Our findings support the theory that the neuroblast timer series was co-opted for use in insect segment patterning, and contribute to our growing understanding of the evolution and function of the gap gene network outside of Drosophila.

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Proteinase-activated receptors in ovine cervical function

Reproduction Fertility and Development ◽

10.1071/rd05032 ◽

2005 ◽

Vol 17 (7) ◽

pp. 693 ◽

Cited By ~ 3

Author(s):

Sharon E. Mitchell ◽

John J. Robinson ◽

Margaret E. King ◽

Lynda M. Williams

Keyword(s):

Gene Expression ◽

In Situ Hybridisation ◽

Prostaglandin F2α ◽

Cervical Dilation ◽

Proteinase Activated Receptors ◽

Pregnant Ewe ◽

High Level ◽

And Function

In sheep, inflammation not only functions in cervical dilation at parturition, but also plays an important part in the non-pregnant ewe cervix, as demonstrated by the high level of expression of interleukin (IL)-8 at oestrus. Ewes artificially induced to ovulate have significantly lower levels of IL-8 gene expression at oestrus compared with natural oestrus, indicating an inhibition of inflammation and function, offering an explanation for the low rates of conception in vaginally inseminated synchronised ewes. To identify potential pro-inflammatory agents to combat the anti-inflammatory effects of hormonal synchronisation of oestrus, we have investigated the role of proteinase-activated receptor (PAR)-1 and PAR-2. To localise and measure the level of expression of these receptors, ovine-specific probes were derived for PAR-1 and PAR-2 and used for quantitative in situ hybridisation in the ovine cervix. Both PAR-1 and PAR-2 were expressed in the luminal epithelium of the cervix throughout the oestrous cycle, with expression being highest at oestrus. The gene expression of PAR-2 at oestrus was approximately 30% higher than that of PAR-1. Artificial synchronisation of oestrus by either an intravaginal progesterone sponge or prostaglandin F2α injections did not inhibit PAR-1 or PAR-2 expression at oestrus; rather, in the case of PAR-2, progesterone synchronisation increased it. Both synchronising procedures increased the expression of PAR-1 and PAR-2 during the luteal phase of the cycle. Therefore, agonists of PAR-1 and PAR-2 may be potentially useful pro-inflammatory agents countering the inhibition of inflammation by hormonal synchronisation.

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Mouse Hox-3.4: homeobox sequence and embryonic expression patterns compared with other members of the Hox gene network

Development ◽

10.1242/dev.109.2.329 ◽

1990 ◽

Vol 109 (2) ◽

pp. 329-339 ◽

Cited By ~ 6

Author(s):

S.J. Gaunt ◽

P.L. Coletta ◽

D. Pravtcheva ◽

P.T. Sharpe

Keyword(s):

Gene Network ◽

Common Ancestor ◽

Expression Patterns ◽

Homeobox Gene ◽

Predicted Amino Acid Sequence ◽

Chromosome 15 ◽

Hox Gene ◽

The Central Nervous System ◽

Genomic Organisation

A putative mouse homeobox gene (Hox-3.4) was previously identified 4kb downstream of the Hox-3.3 (Hox-6.1)* gene (Sharpe et al. 1988). We have now sequenced the Hox-3.4 homeobox region. The predicted amino acid sequence shows highest degree of homology in the mouse with Hox-1.3 and -2.1. This, together with similarities in the genomic organisation around these three genes, suggests that they are comembers of a subfamily, derived from a common ancestor. Hox-3.4 appears to be a homologue of the Xenopus Xlhbox5 and human cp11 genes (Fritz and De Robertis, 1988; Simeone et al. 1988). Using a panel of mouse-hamster somatic cell hybrids we have mapped the Hox-3.4 gene to chromosome 15. From the results of in situ hybridization experiments, we describe the distribution of Hox-3.4 transcripts within the 12 1/2 day mouse embryo, and we compare this with the distributions of transcripts shown by seven other members of the Hox gene network. We note three consistencies that underlie the patterns of expression shown by Hox-3.4. First, the anterior limits of Hox-3.4 transcripts in the embryo are related to the position of the Hox-3.4 gene within the Hox-3 locus. Second, the anterior limits of Hox-3.4 expression within the central nervous system are similar to those shown by subfamily homologues Hox-2.1 and Hox-1.3, although the tissue-specific patterns of expression for these three genes show many differences. Third, the patterns of Hox-3.4 expression within the spinal cord and the testis are very similar to those shown by a neighbouring Hox-3 gene (Hox-3.3), but they are quite different from those shown by Hox-1 genes (Hox-1.2, -1.3 and -1.4).

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tarsal-less is expressed as a gap gene but has no gap gene phenotype in the moth midge Clogmia albipunctata

Royal Society Open Science ◽

10.1098/rsos.180458 ◽

2018 ◽

Vol 5 (8) ◽

pp. 180458 ◽

Cited By ~ 2

Author(s):

Eva Jiménez-Guri ◽

Karl R. Wotton ◽

Johannes Jaeger

Keyword(s):

Gene Expression ◽

Drosophila Melanogaster ◽

Rna Interference ◽

Gap Gene ◽

Gap Genes ◽

Subtle Effect ◽

Bona Fide ◽

Vinegar Fly ◽

Clogmia Albipunctata ◽

Overlapping Domains

Gap genes are involved in segment determination during early development of the vinegar fly Drosophila melanogaster and other dipteran insects (flies, midges and mosquitoes). They are expressed in overlapping domains along the antero-posterior (A–P) axis of the blastoderm embryo. While gap domains cover the entire length of the A–P axis in Drosophila, there is a region in the blastoderm of the moth midge Clogmia albipunctata , which lacks canonical gap gene expression. Is a non-canonical gap gene functioning in this area? Here, we characterize tarsal-less ( tal ) in C. albipunctata . The homologue of tal in the flour beetle Tribolium castaneum (called milles-pattes, mlpt ) is a bona fide gap gene. We find that Ca-tal is expressed in the region previously reported as lacking gap gene expression. Using RNA interference, we study the interaction of Ca-tal with gap genes. We show that Ca-tal is regulated by gap genes, but only has a very subtle effect on tailless (Ca-tll), while not affecting other gap genes at all. Moreover, cuticle phenotypes of Ca-tal depleted embryos do not show any gap phenotype. We conclude that Ca-tal is expressed and regulated like a gap gene, but does not function as a gap gene in C. albipunctata .

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Expression of p53 during mouse embryogenesis

Development ◽

10.1242/dev.113.3.857 ◽

1991 ◽

Vol 113 (3) ◽

pp. 857-865 ◽

Cited By ~ 4

Author(s):

P. Schmid ◽

A. Lorenz ◽

H. Hameister ◽

M. Montenarh

Keyword(s):

Gene Expression ◽

Cellular Differentiation ◽

Cellular Proliferation ◽

In Situ Hybridisation ◽

Terminal Differentiation ◽

Mouse Embryogenesis ◽

Differentiated Cells ◽

The Brain ◽

P53 Mrna

By in situ hybridisation we have examined the expression of p53 during mouse embryogenesis from day 8.5 to day 18.5 post coitum (p.c.). High levels of p53 mRNA were detected in all cells of the day 8.5 p.c. and 10.5 p.c. mouse embryo. However, at later stages of development, expression became more pronounced during differentiation of specific tissues e.g. of the brain, liver, lung, thymus, intestine, salivary gland and kidney. In cells undergoing terminal differentiation, the level of p53 mRNA declined strongly. In the brain, hybridisation signals were also observed in postmitotic but not yet terminally differentiated cells. Therefore, gene expression of p53 does not appear to be linked with cellular proliferation in this organ. A proposed role for p53 in cellular differentiation is discussed.

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Structure and function of a nitrifying biofilm as determined by microelectrodes and fluorescent oligonucleotide probes

Water Science & Technology ◽

10.2166/wst.1997.0062 ◽

1997 ◽

Vol 36 (1) ◽

pp. 263-270 ◽

Cited By ~ 13

Author(s):

A. Schramm ◽

L. H. Larsen ◽

N. P. Revsbech ◽

R. I. Amann

Keyword(s):

In Situ Hybridisation ◽

Bulk Water ◽

Nitrifying Bacteria ◽

Dense Layer ◽

Oligonucleotide Probes ◽

O2 Concentration ◽

Measured Activity ◽

And Function ◽

The Vertical Distribution

Microelectrodes for O2 and NO2−/NO3− and fluorescently labelled 16S rRNA-targeted oligonucleotide probes were combined to examine the activity and stratification of nitrifying bacteria in a trickling filter biofilm. Microprofiles showed that O2 consumption and NO3−/NO2− production were restricted to the upper 50-100 μm of the biofilm. The vertical distribution of the nitrifying bacteria Nitrosomonas sp. and Nitrobacter sp. was investigated by fluorescent in situ hybridisation (FISH) with specific oligonucleotides. Nitrifiers formed a dense layer of cells and cell clusters in the upper part of the biofilm. This correlates well with the measured activity profiles. Ammonia- and nitrite-oxidisers occurred in close vicinity to each other supporting a fast sequential metabolism from ammonia to nitrate. Both species were not restricted to the oxic part of the biofilm, but also appeared -in lower numbers- in the anoxic layers on the bottom of the biofilm. A short term decrease in the O2 concentration of the bulk water resulted in a quick decrease in O2 penetration and metabolic rates inside the biofilm. However, neither the stratification nor the cellular ribosome content of nitrifiers changed within a few hours.

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