Temperature controls nuclear import of Tam3 transposase in Antirrhinum

Abstract

SUMMARYIt has been proposed that environmental stimuli can activate transposable elements (TEs), whereas few substantial mechanisms have been shown so far. The class-II element Tam3 from Antirrhinum majus exhibits a unique property of low-temperature-dependent transposition (LTDT). LTDT has proved invaluable in developing the gene isolation technologies that have underpinned much of modern plant developmental biology. Here, we reveal that LTDT involves differential subcellular localization of the Tam3 transposase (TPase) in cells grown at low (15°C) and high (25°C) temperatures. The mechanism is associated with the nuclear import of Tam3 TPase in Antirrhinum cells. At high temperature, the nuclear import of Tam3 TPase is severely restricted in Antirrhinum cells, whereas at low temperature, the nuclear localization of Tam3 TPase is observed in about 20% of the cells. However, in tobacco BY-2 and Allium cepa (onion) cells, Tam3 TPase is transported into most nuclei. In addition to three nuclear localization signals (NLSs), the Tam3 TPase is equipped with a nuclear localization inhibitory domain (NLID), which functions to abolish nuclear import of the TPase at high temperature in Antirrhinum. NLID in Tam3 TPase is considered to interact with Antirrhinumspecific factor(s). The host-specific regulation of the nuclear localization of transposase represents a new repertoire controlling class-II TEs.

Comprehensive Modelling of the Neurospora Circadian Clock and Its Temperature Compensation

“…Temperature dependent translocation of proteins has been reported in other organisms, for example in rat fibroblasts the temperature-sensitive mutant of p53 (p53 val-5 ) is predominantly in the cytoplasm at 37.5 °C but moves to the nucleus at 32.5 °C [76]. Another example of a protein whose localisation is temperature-dependent is the Antirrhinum Tam3 transposase, which is restricted to the cytoplasm at 25 °C, but translocates into the nucleus at 15 °C [77]. Interestingly, translocation between cytoplasm and nucleus of the Drosophila clock protein PER is restricted in the ritsu mutant at higher temperatures, resulting in lengthening the period of the clock [78].…”

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“…Thus, stress can induce TE activity, which can create intragenomic potential at opportune times to facilitate adaptation in response to environmental challenge (Zeh et al 2009; Casacuberta and González 2013). In angiosperms, TE mobilization has been reported for a variety of abiotic or biotic stress conditions including high or low temperatures, UV light, wounding, and pathogen attack (Mhiri et al 1997; Walbot 1999; Grandbastien et al 2005; Fujino et al 2011; Matsunaga et al 2012). Tolerance to one stress factor in particular, fire, has been a major factor in the success of many angiosperms (Keeley et al 2011), including grasses and resprouting plants that are long lived and rarely reproduce from seed.…”

Transposable elements and human cancer: A causal relationship?

“…In general, active TE transposition in living organisms can be induced by a number of environmental factors, like heat shock, viral infection, various chemicals, γ irradiation, etc. [86][87][88][89][90]. Although not clearly established, environmentally-induced TE activation could, albeit indirectly, contribute to human carcinogenesis.…”