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171 results on '"Jackson, F. Rob"'

7. A new biological rhythm mutant of Drosophila melanogaster that identifies a gene with an essential embryonic function

Author

Newby, L.M. and Jackson, F. Rob

Subjects
Drosophila -- Genetic aspects, Circadian rhythms -- Observations, Molecular genetics -- Research, Phenotype -- Analysis, Biological sciences
Abstract

Drosophila mutation, which renders changes in eclosion timing without affecting the circadian rhythm, facilitates the detection of elements involved in the circadian pacemaker output mechanisms. Lark gene is one such element identified, and is characterized by a single P-element insertion with a potential to alter eclosion timing. Lark gene, which is related to a recessive embryonic lethal phenotype, has a vital embryonic function. Results obtained during analysis of mutant phenotypes underscores the proposition of LARK function which corresponds to the pleiotropic character of lark mutants.

Published
1993

12. Genetic Analysis of Functional Domains Within the Drosophila LARK RNA-Binding Protein

Author

McNeil, Gerard P., Schroeder, Andrew J., Roberts, Mary A., and Jackson, F. Rob

Subjects
Drosophila -- Genetic aspects, RNA -- Genetic aspects, Embryology -- Genetic aspects, Genetic research -- Analysis, Biological sciences
Abstract

LARK is an essential Drosophila RNA-binding protein of the RNA recognition motif (RRM) class that functions during embryonic development and for the circadian regulation of adult eclosion. LARK protein contains three consensus RNA-binding domains: two RRM domains and a retroviral-type zinc finger (RTZF). To show that these three structural domains are required for function, we performed a site-directed mutagenesis of the protein. The analysis of various mutations, in vivo, indicates that the RRM domains and the RTZF are required for wild-type LARK functions. RRM1 and RRM2 are essential for viability, although interestingly either domain can suffice for this function. Remarkably, mutation of either RRM2 or the RTZF results in the same spectrum of phenotypes: mutants exhibit reduced viability, abnormal wing and mechanosensory bristle morphology, female sterility, and flightlessness. The severity of these phenotypes is similar in single mutants and double RRM2; RTZF mutants, indicating a lack of additivity for the mutations and suggesting that RRM2 and the RTZF act together, in vivo, to determine LARK function. Finally, we show that mutations in RRM1, RRM2, or the RTZF do not affect the circadian regulation of eclosion, and we discuss possible interpretations of these results. This genetic analysis demonstrates that each of the LARK structural domains functions in vivo and indicates a pleiotropic requirement for both the LARK RRM2 and RTZF domains.

Published
2001

19. Dispensable, Redundant, Complementary, and Cooperative Roles of Dopamine, Octopamine, and Serotonin in Drosophila melanogaster

Author

Chen, Audrey, primary, Ng, Fanny, additional, Lebestky, Tim, additional, Grygoruk, Anna, additional, Djapri, Christine, additional, Lawal, Hakeem O, additional, Zaveri, Harshul A, additional, Mehanzel, Filmon, additional, Najibi, Rod, additional, Seidman, Gabriel, additional, Murphy, Niall P, additional, Kelly, Rachel L, additional, Ackerson, Larry C, additional, Maidment, Nigel T, additional, Jackson, F Rob, additional, and Krantz, David E, additional

Published
2013
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49. Ribosomal S6 Kinase Cooperates with Casein Kinase 2 to Modulate the Drosophila Circadian Molecular Oscillator.

Author

Akten, Bikem, Tangredi, Michelle M., Jauch, Eike, Roberts, Mary A., Ng, Fanny, Raabe, Thomas, and Jackson, F. Rob

Subjects
PROTEIN kinase CK2, CIRCADIAN rhythms, NUCLEAR reactions, GENETIC regulation, RIBOSOMES, DROSOPHILA
Abstract

There is a universal requirement for post-translational regulatory mechanisms in circadian clock systems. Previous work in Drosophila has identified several kinases, phosphatases, and an E3 ligase that are critical for determining the nuclear translocation and/or stability of clock proteins. The present study evaluated the function of p90 ribosomal S6 kinase (RSK) in the Drosophila circadian system. In mammals, RSK1 is a light- and clock-regulated kinase known to be activated by the mitogen-activated protein kinase pathway, but there is no direct evidence that it functions as a component of the circadian system. Here, we show that Drosophila S6KIIRNAdisplays rhythms in abundance, indicative of circadian control. Importantly, an S6KII null mutant exhibits a short-period circadian phenotype that can be rescued by expression of the wild-type gene in clock neurons, indicating a role for S6KII in the molecular oscillator. Peak PER clock protein expression is elevated in the mutant, indicative of enhanced stability, whereas per mRNA level is decreased, consistent with enhanced feedback repression. Gene reporter assays show that decreased S6KII is associated with increased PER repression. Surprisingly, we demonstrate a physical interaction between S6KII and the casein kinase 2 regulatory subunit (CK2β), suggesting a functional relationship between the two kinases. In support of such a relationship, there are genetic interactions between S6KII and CK2 mutations, in vivo, which indicate that CK2 activity is required for S6KII action. We propose that the two kinases cooperate within clock neurons to fine-tune circadian period, improving the precision of the clock mechanism. [ABSTRACT FROM AUTHOR]

Published
2009
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