The zygotic control of Drosophila pair-rule gene expression. I. A search for new pair-rule regulatory loci

Development ◽  
1989 ◽  
Vol 107 (3) ◽  
pp. 663-672 ◽  
Author(s):  
S.H. Vavra ◽  
S.B. Carroll
Keyword(s):  
Gene Expression ◽  
Regulatory System ◽  
Wild Type ◽  
Periodic Patterns ◽  
Pair Rule Gene ◽  
New Type ◽  
Regulatory Loci ◽  
Direct Inspection ◽  
Pair Rule ◽  
Zygotic Control

The examination of pair-rule gene expression in wild-type and segmentation mutant embryos has identified many, but not necessarily all, of the elements of the regulatory system that establish their periodic patterns. Here we have conducted a new type of search for previously unknown regulators of these genes by examining pair-rule gene expression in blastoderm embryos lacking parts of or entire chromosomes. This method has the advantage of direct inspection of abnormal pair-rule gene patterns without relying upon mutagenesis or interpretation of larval phenotypes for the identification of segmentation genes. From these experiments we conclude that: (i) most zygotically required regulators of the fushi tarazu (ftz), even-skipped (eve) and hairy (h) pair-rule genes have been identified, except for one or more loci we have uncovered on chromosome arm 2L; (ii) the repression of the ftz and eve genes in the anterior third of the embryo is under maternal, not zygotic control; and (iii) there are no general zygotically required activators of pair-rule gene expression. The results suggest that the molecular basis of pair-rule gene regulation can be pursued with greater confidence now that most key trans-acting factors are already in hand.

The zygotic control of Drosophila pair-rule gene expression. II. Spatial repression by gap and pair-rule gene products

Development ◽  
1989 ◽  
Vol 107 (3) ◽  
pp. 673-683 ◽  
Author(s):  
S.B. Carroll ◽  
S.H. Vavra
Keyword(s):  
Gene Expression ◽  
Expression Patterns ◽  
Control Mechanisms ◽  
Gap Gene ◽  
Gap Genes ◽  
Gene Mutant ◽  
Pair Rule Gene ◽  
Regulatory Effects ◽  
Pair Rule ◽  
Zygotic Control

We examined gene expression patterns in certain single and double pair-rule mutant embryos to determine which of the largely repressive pair-rule gene interactions are most likely to be direct and which interactions are probably indirect. From these studies we conclude that: (i) hairy+ and even-skipped (eve+) regulate the fushi tarazu (ftz) gene; (ii) eve+ and runt+ regulate the hairy gene; (iii) runt+ regulates the eve gene; but, (iv) runt does not regulate the ftz gene pattern, and hairy does not regulate the eve gene pattern. These pair-rule interactions are not sufficient, however, to explain the periodicity of the hairy and eve patterns, so we examined specific gap gene mutant combinations to uncover their regulatory effects on these two genes. Our surprising observation is that the hairy and eve genes are expressed in embryos where the three key gap genes hunchback (hb), Kruppel (Kr), and knirps (kni) have been removed, indicating that these gap genes are not essential to activate the pair-rule genes. In fact, we show that in the absence of either hb+ or kni+, or both gap genes, the Kr+ product represses hairy expression. These results suggest that gap genes repress hairy expression in the interstripe regions, rather than activate hairy expression in the stripes. The molecular basis of pair-rule gene regulation by gap genes must involve some dual control mechanisms such that combinations of gap genes affect pair-rule transcription in a different manner than a single gap gene.

scholarly journals Odd-paired controls frequency doubling in Drosophila segmentation by altering the pair-rule gene regulatory network

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Erik Clark ◽  
Michael Akam
Keyword(s):  
Gene Expression ◽  
Gene Regulatory Network ◽  
Regulatory Network ◽  
Frequency Doubling ◽  
Drosophila Embryo ◽  
Anteroposterior Patterning ◽  
Regulatory Interactions ◽  
Pair Rule Gene ◽  
Gene Regulatory ◽  
Pair Rule

The Drosophila embryo transiently exhibits a double-segment periodicity, defined by the expression of seven 'pair-rule' genes, each in a pattern of seven stripes. At gastrulation, interactions between the pair-rule genes lead to frequency doubling and the patterning of 14 parasegment boundaries. In contrast to earlier stages of Drosophila anteroposterior patterning, this transition is not well understood. By carefully analysing the spatiotemporal dynamics of pair-rule gene expression, we demonstrate that frequency-doubling is precipitated by multiple coordinated changes to the network of regulatory interactions between the pair-rule genes. We identify the broadly expressed but temporally patterned transcription factor, Odd-paired (Opa/Zic), as the cause of these changes, and show that the patterning of the even-numbered parasegment boundaries relies on Opa-dependent regulatory interactions. Our findings indicate that the pair-rule gene regulatory network has a temporally modulated topology, permitting the pair-rule genes to play stage-specific patterning roles.

Dose-dependent regulation of pair-rule stripes by gap proteins and the initiation of segment polarity

Development ◽  
1990 ◽  
Vol 110 (3) ◽  
pp. 759-767 ◽  
Author(s):  
R. Warrior ◽  
M. Levine
Keyword(s):  
Expression Patterns ◽  
Gene Products ◽  
Embryonic Cells ◽  
Periodic Patterns ◽  
Threshold Response ◽  
Gap Gene ◽  
Relative Placement ◽  
Segment Polarity ◽  
Pair Rule Gene ◽  
Pair Rule

A key step in Drosophila segmentation is the establishment of periodic patterns of pair-rule gene expression in response to gap gene products. From an examination of the distribution of gap and pair-rule proteins in various mutants, we conclude that the on/off periodicity of pair-rule stripes depends on both the exact concentrations and combinations of gap proteins expressed in different embryonic cells. It has been suggested that the distribution of gap gene products depends on cross-regulatory interactions among these genes. Here we provide evidence that autoregulation also plays an important role in this process since there is a reduction in the levels of Kruppel (Kr) RNA and protein in a Kr null mutant. Once initiated by the gap genes each pair-rule stripe is bell shaped and has ill-defined margins. By the end of the fourteenth nuclear division cycle, the stripes of the pair-rule gene even-skipped (eve) sharpen and polarize, a process that is essential for the precisely localized expression of segment polarity genes. This sharpening process appears to depend on a threshold response of the eve promoter to the combinatorial action of eve and a second pair-rule gene hairy. The eve and hairy expression patterns overlap but are out of register and the cells of maximal overlap form the anterior margin of the polarized eve stripe. We propose that the relative placement of the eve and hairy stripes may be an important factor in the initiation of segment polarity.

scholarly journals Conservation and variation in pair-rule gene expression and function in the intermediate-germ beetleDermestes maculatus

Development ◽  
2017 ◽  
Vol 144 (24) ◽  
pp. 4625-4636 ◽  
Author(s):  
Jie Xiang ◽  
Katie Reding ◽  
Alison Heffer ◽  
Leslie Pick
Keyword(s):  
Gene Expression ◽  
Pair Rule Gene ◽  
And Function ◽  
Pair Rule

scholarly journals The Wnt and Delta-Notch signalling pathways interact to direct pair-rule gene expression viacaudalduring segment addition in the spiderParasteatoda tepidariorum

Development ◽  
2016 ◽  
Vol 143 (13) ◽  
pp. 2455-2463 ◽  
Author(s):  
Anna Schönauer ◽  
Christian L. B. Paese ◽  
Maarten Hilbrant ◽  
Daniel J. Leite ◽  
Evelyn E. Schwager ◽  
...  
Keyword(s):  
Gene Expression ◽  
Notch Signalling ◽  
Signalling Pathways ◽  
Pair Rule Gene ◽  
Pair Rule

scholarly journals Conjugal Transfer but Not Quorum-Dependenttra Gene Induction of pTiC58 Requires a Solid Surface

1999 ◽  
Vol 65 (6) ◽  
pp. 2798-2801 ◽  
Author(s):  
Kevin R. Piper ◽  
Stephen K. Farrand
Keyword(s):  
Gene Expression ◽  
Agrobacterium Tumefaciens ◽  
Liquid Medium ◽  
Solid Surface ◽  
High Frequency ◽  
Solid Medium ◽  
Regulatory System ◽  
Ti Plasmid ◽  
Solid Surfaces ◽  
Wild Type

ABSTRACT Donors of Agrobacterium tumefaciens harboring a transfer-constitutive derivative of the nopaline-type Ti plasmid pTiC58 transferred this element at frequencies 3 to 4 orders of magnitude higher in matings conducted on solid surfaces than in those conducted in liquid medium. However, as measured with a lacZ reporter fusion, the tra genes of the wild-type Ti plasmid were inducible by opines to indistinguishable levels on solid and in liquid medium. Donors induced in liquid transferred the Ti plasmid at high frequency when mated with recipients on solid medium. We conclude that while formation of stable mating pairs and subsequent transfer of the Ti plasmid is dependent on a solid stratum, the regulatory system can activate tra gene expression to equivalent levels in liquid and on solid surfaces.

scholarly journals Odd-paired controls frequency doubling in Drosophila segmentation by altering the pair-rule gene regulatory network

2016 ◽  
Author(s):  
Erik Clark ◽  
Michael Akam
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Gene Regulatory Network ◽  
Regulatory Network ◽  
Frequency Doubling ◽  
Anteroposterior Patterning ◽  
Regulatory Interactions ◽  
Pair Rule Gene ◽  
Gene Regulatory ◽  
Pair Rule

ABSTRACTThe Drosophila embryo transiently exhibits a double segment periodicity, defined by the expression of seven “pair-rule” genes, each in a pattern of seven stripes. At gastrulation, interactions between the pair-rule genes lead to frequency doubling and the patterning of fourteen parasegment boundaries. In contrast to earlier stages of Drosophila anteroposterior patterning, this transition is not well understood. By carefully analysing the spatiotemporal dynamics of pair-rule gene expression, we demonstrate that frequency-doubling is precipitated by multiple coordinated changes to the network of regulatory interactions between the pair-rule genes. We identify the broadly expressed but temporally patterned transcription factor, Odd-paired (Opa/Zic), as the cause of these changes, and show that the patterning of the even-numbered parasegment boundaries relies on Opa-dependent regulatory interactions. Our findings indicate that the pair-rule gene regulatory network has a temporally-modulated topology, permitting the pair-rule genes to play stage-specific patterning roles.

scholarly journals Abh and AbrB Control of Bacillus subtilis Antimicrobial Gene Expression

2007 ◽  
Vol 189 (21) ◽  
pp. 7720-7732 ◽  
Author(s):  
Mark A. Strauch ◽  
Benjamin G. Bobay ◽  
John Cavanagh ◽  
Fude Yao ◽  
Angelo Wilson ◽  
...  
Keyword(s):  
Gene Expression ◽  
Bacillus Subtilis ◽  
Regulatory Protein ◽  
Regulatory System ◽  
Regulatory Role ◽  
Wild Type ◽  
Promoter Regions ◽  
Active Growth ◽  
Positive Role ◽  
Dnase I Footprinting

ABSTRACT The Bacillus subtilis abh gene encodes a protein whose N-terminal domain has 74% identity to the DNA-binding domain of the global regulatory protein AbrB. Strains with a mutation in abh showed alterations in the production of antimicrobial compounds directed against some other Bacillus species and gram-positive microbes. Relative to its wild-type parental strain, the abh mutant was found deficient, enhanced, or unaffected for the production of antimicrobial activity. Using lacZ fusions, we examined the effects of abh upon the expression of 10 promoters known to be regulated by AbrB, including five that transcribe well-characterized antimicrobial functions (SdpC, SkfA, TasA, sublancin, and subtilosin). For an otherwise wild-type background, the results show that Abh plays a negative regulatory role in the expression of four of the promoters, a positive role for the expression of three, and no apparent regulatory role in the expression of the other three promoters. Binding of AbrB and Abh to the promoter regions was examined using DNase I footprinting, and the results revealed significant differences. The transcription of abh is not autoregulated, but it is subject to a degree of AbrB-afforded negative regulation. The results indicate that Abh is part of the complex interconnected regulatory system that controls gene expression during the transition from active growth to stationary phase.

Evolution of neuroblast identity: seven-up and prospero expression reveal homologous and divergent neuroblast fates in Drosophila and Schistocerca

Development ◽  
1995 ◽  
Vol 121 (12) ◽  
pp. 3989-3996 ◽  
Author(s):  
J. Broadus ◽  
C.Q. Doe
Keyword(s):  
Gene Expression ◽  
Central Nervous System ◽  
Gene Function ◽  
Fushi Tarazu ◽  
Pair Rule Gene ◽  
Key Features ◽  
Insect Central Nervous System ◽  
Or Gene ◽  
Species Specific ◽  
Pair Rule

In the Drosophila CNS, early neuroblast formation and fate are controlled by the pair-rule class of segmentation genes. The distantly related Schistocerca (grasshopper) embryo has a similar arrangement of neuroblasts, despite lack of known pair-rule gene function. Does divergent pair-rule gene function lead to different neuroblast identities, or can different patterning mechanisms produce homologous neuroblasts? We use four molecular markers to compare Drosophila and Schistocerca neuroblast identity: seven-up, prospero, engrailed, and fushi-tarazu/Dax. In both insects some early-forming neuroblasts share key features of neuroblast identity (position, time of formation, and temporally accurate gene expression); thus, different patterning mechanisms can generate similar neuroblast fates. In contrast, several later-forming neuroblasts show species-specific differences in position and/or gene expression; these neuroblast identities seem to have diverged, suggesting that evolution of the insect central nervous system can occur through changes in embryonic neuroblast identity.

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