Role of Tau, a microtubule associated protein, in Drosophila photoreceptor morphogenesis

Abstract

Cell polarity genes have important functions in photoreceptor morphogenesis. Based on recent discovery of stabilized microtubule cytoskeleton in developing photoreceptors and its role in photoreceptor cell polarity, microtubule associated proteins might have important roles in controlling cell polarity proteins' localizations in developing photoreceptors. Here, Tau, a microtubule associated protein, was analyzed to find its potential role in photoreceptor cell polarity. Tau colocalizes with acetylated/stabilized microtubules in developing pupal photoreceptors. Although it is known that tau mutant photoreceptor has no defects in early eye differentiation and development, it shows dramatic disruptions of cell polarity proteins, adherens junctions, and the stable microtubules in developing pupal photoreceptors. This role of Tau in cell polarity proteins' localization in photoreceptor cells during the photoreceptor morphogenesis was further supported by Tau's overexpression studies. Tau overexpression caused dramatic expansions of apical membrane domains where the polarity proteins localize in the developing pupal photoreceptors. It is also found that Tau's role in photoreceptor cell polarity depends on Par-1 kinase. Furthermore, a strong genetic interaction between tau and crumbs was found. It is found that Tau has a crucial role in cell polarity protein localization during pupal photoreceptor morphogenesis stage, but not in early eye development including eye cell differentiation.

Identification of Genes Required for Apical Protein Trafficking inDrosophilaPhotoreceptor Cells

“…Klc-deficient PRCs (but not Khc-deficient cells) also showed a reduction in Crb (Figure S4). Microtubules and microtubule-related proteins are known to be important for Crb trafficking in pupal PRCs (Mukhopadhyay et al , 2010; Chen et al , 2010; League and Nam 2011; Mui et al , 2011; Nam 2016). It is not clear whether this Crb defect is specific to Klc knockdown or if a stronger knockdown of Khc or Dhc64C would affect Crb in a similar manner.…”

“…Crb and Eys are thought to be targeted to the stalk through a pathway distinct from the secretory pathway used by rhabdomeral proteins (Beronja et al , 2005, Husain et al , 2006). The components involved in Crb and Eys exocytosis are currently unknown, except for evidence suggesting that microtubules and microtubule motor proteins are involved in Crb localization during pupal stages (Mukhopadhyay et al , 2010; Chen et al , 2010; League and Nam 2011; Mui et al , 2011; Nam 2016).…”

Integration of a faculty's ongoing research into an undergraduate laboratory teaching class in developmental biology

“…The pupal eye development was utilized for the instructor's main research material for the last 16 years. The instructor has analyzed cell polarity, cell junctions, and cytoskeletons using this important organogenesis model system [9,10,[12][13][14][15][22][23][24][25][26][27].…”

Use of Immunolabeling to Analyze Stable, Dynamic, and Nascent Microtubules in the Zebrafish Embryo

“…This method can be applied to address questions regarding morphogenesis and the establishment or maturation of cell polarity 20 . Indeed, the elaboration of polarized arrays of stable MTs accompanies many developmental events, including photoreceptor morphogenesis 21 , epithelialization of cells in the developing neural tube 18 and axon formation . Nascent MTs are nucleated at the centrosome and subsequently anchored to subdistal appendages of the mother centriole 23 .…”