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Publications

PLK4 trans-Autoactivation Controls Centriole Biogenesis in Space

Publication . Lopes, Carla A.M.; Jana, Swadhin Chandra; Cunha-Ferreira, Inês; Zitouni, Sihem; Bento, Inês; Duarte, Paulo; Gilberto, Samuel; Freixo, Francisco; Guerrero, Adán; Francia, Maria; Lince-Faria, Mariana; Carneiro, Jorge; Bettencourt-Dias, Mónica

Centrioles are essential for cilia and centrosome assembly. In centriole-containing cells, centrioles always form juxtaposed to pre-existing ones, motivating a century-old debate on centriole biogenesis control. Here, we show that trans-autoactivation of Polo-like kinase 4 (PLK4), the trigger of centriole biogenesis, is a critical event in the spatial control of that process. We demonstrate that centrioles promote PLK4 activation through its recruitment and local accumulation. Though centriole removal reduces the proportion of active PLK4, this is rescued by concentrating PLK4 to the peroxisome lumen. Moreover, while mild overexpression of PLK4 only triggers centriole amplification at the existing centriole, higher PLK4 levels trigger both centriolar and cytoplasmatic (de novo) biogenesis. Hence, centrioles promote their assembly locally and disfavor de novo synthesis. Similar mechanisms enforcing the local concentration and/or activity of other centriole components are likely to contribute to the spatial control of centriole biogenesis under physiological conditions.

2015-10-26Journal article

Open access

Methods to Study Centrosomes and Cilia in Drosophila

Publication . Jana, Swadhin Chandra; Mendonça, Susana; Werner, Sascha; Bettencourt-Dias, Monica

Centrioles and cilia are highly conserved eukaryotic organelles. Drosophila melanogaster is a powerful genetic and cell biology model organism, extensively used to discover underlying mechanisms of centrosome and cilia biogenesis and function. Defects in centrosomes and cilia reduce fertility and affect different sensory functions, such as proprioception, olfaction, and hearing. The fly possesses a large diversity of ciliary structures and assembly modes, such as motile, immotile, and intraflagellar transport (IFT)-independent or IFT-dependent assembly. Moreover, all the diverse ciliated cells harbor centrioles at the base of the cilia, called basal bodies, making the fly an attractive model to better understand the biology of this organelle. This chapter describes protocols to visualize centrosomes and cilia by fluorescence and electron microscopy.

2016-08-12Preprint

Open access

A mechanism for the elimination of the female gamete centrosome in Drosophila melanogaster

Publication . Pimenta-Marques, A.; Bento, I.; Lopes, C. A. M.; Duarte, P.; Jana, S. C.; Bettencourt-Dias, M.

An important feature of fertilization is the asymmetric inheritance of centrioles. In most species it is the sperm that contributes the initial centriole, which builds the first centrosome that is essential for early development. However, given that centrioles are thought to be exceptionally stable structures, the mechanism behind centriole disappearance in the female germ line remains elusive and paradoxical. We elucidated a program for centriole maintenance in fruit flies, led by Polo kinase and the pericentriolar matrix (PCM): The PCM is down-regulated in the female germ line during oogenesis, which results in centriole loss. Perturbing this program prevents centriole loss, leading to abnormal meiotic and mitotic divisions, and thus to female sterility. This mechanism challenges the view that centrioles are intrinsically stable structures and reveals general functions for Polo kinase and the PCM in centriole maintenance. We propose that regulation of this maintenance program is essential for successful sexual reproduction and defines centriole life span in different tissues in homeostasis and disease, thereby shaping the cytoskeleton.

2016-07-01Journal article

Open access

Drosophila melanogaster as a model for basal body research

Publication . Jana, Swadhin Chandra; Bettencourt-Dias, Mónica; Durand, Bénédicte; Megraw, Timothy L.

The fruit fly, Drosophila melanogaster, is one of the most extensively studied organisms in biological research and has centrioles/basal bodies and cilia that can be modelled to investigate their functions in animals generally. Centrioles are nine-fold symmetrical microtubule-based cylindrical structures required to form centrosomes and also to nucleate the formation of cilia and flagella. When they function to template cilia, centrioles transition into basal bodies. The fruit fly has various types of basal bodies and cilia, which are needed for sensory neuron and sperm function. Genetics, cell biology and behaviour studies in the fruit fly have unveiled new basal body components and revealed different modes of assembly and functions of basal bodies that are conserved in many other organisms, including human, green algae and plasmodium. Here we describe the various basal bodies of Drosophila, what is known about their composition, structure and function.

2016-07-05Journal article

Open access