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Producción Científica, The Fas-activated serine/threonine kinase (FASTK) family of proteins has recently emerged as a central regulator of mitochondrial gene expression through the function of an unusual RNA-binding domain named RAP (for RNA-binding domain abundant in Apicomplexans), shared by all six members of the family. Here we describe the role of one of the less characterized members, FASTKD3, in mitochondrial RNA metabolism. First, we show that, in contrast to FASTK, FASTKD2, and FASTKD5, FASTKD3 does not localize in mitochondrial RNA granules, which are sites of processing and maturation of mtRNAs and ribosome biogenesis. Second, we generated FASTKD3 homozygous knock-out cell lines by homologous recombination and observed that the absence of FASTKD3 resulted in increased steady-state levels and half-lives of a subset of mature mitochondrial mRNAs: ND2, ND3, CYTB, COX2, and ATP8/6. No aberrant processing of RNA precursors was observed. Rescue experiments demonstrated that RAP domain is required for FASTKD3 function in mRNA stability. Besides, we describe that FASTKD3 is required for efficient COX1 mRNA translation without altering mRNA levels, which results in a decrease in the steady-state levels of COX1 protein. This finding is associated with reduced mitochondrial complex IV assembly and activity. Our observations suggest that the function of this family of proteins goes beyond RNA processing and ribosome assembly and includes RNA stability and translation regulation within mitochondria., Junta de Castilla y León (grants BIO/ VA20/15 and BIO/VA21/15), Swiss National Science Foundation (grant 310030B_160257/1)

Producción Científica, The Fas-activated serine/threonine kinase (FASTK) family of proteins has recently emerged as a central regulator of mitochondrial gene expression through the function of an unusual RNA-binding domain named RAP (for RNA-binding domain abundant in Apicomplexans), shared by all six members of the family. Here we describe the role of one of the less characterized members, FASTKD3, in mitochondrial RNA metabolism. First, we show that, in contrast to FASTK, FASTKD2, and FASTKD5, FASTKD3 does not localize in mitochondrial RNA granules, which are sites of processing and maturation of mtRNAs and ribosome biogenesis. Second, we generated FASTKD3 homozygous knock-out cell lines by homologous recombination and observed that the absence of FASTKD3 resulted in increased steady-state levels and half-lives of a subset of mature mitochondrial mRNAs: ND2, ND3, CYTB, COX2, and ATP8/6. No aberrant processing of RNA precursors was observed. Rescue experiments demonstrated that RAP domain is required for FASTKD3 function in mRNA stability. Besides, we describe that FASTKD3 is required for efficient COX1 mRNA translation without altering mRNA levels, which results in a decrease in the steady-state levels of COX1 protein. This finding is associated with reduced mitochondrial complex IV assembly and activity. Our observations suggest that the function of this family of proteins goes beyond RNA processing and ribosome assembly and includes RNA stability and translation regulation within mitochondria., Junta de Castilla y León (grants BIO/ VA20/15 and BIO/VA21/15), Swiss National Science Foundation (grant 310030B_160257/1)

Producción Científica, The Fas-activated serine/threonine kinase (FASTK) family of proteins has recently emerged as a central regulator of mitochondrial gene expression through the function of an unusual RNA-binding domain named RAP (for RNA-binding domain abundant in Apicomplexans), shared by all six members of the family. Here we describe the role of one of the less characterized members, FASTKD3, in mitochondrial RNA metabolism. First, we show that, in contrast to FASTK, FASTKD2, and FASTKD5, FASTKD3 does not localize in mitochondrial RNA granules, which are sites of processing and maturation of mtRNAs and ribosome biogenesis. Second, we generated FASTKD3 homozygous knock-out cell lines by homologous recombination and observed that the absence of FASTKD3 resulted in increased steady-state levels and half-lives of a subset of mature mitochondrial mRNAs: ND2, ND3, CYTB, COX2, and ATP8/6. No aberrant processing of RNA precursors was observed. Rescue experiments demonstrated that RAP domain is required for FASTKD3 function in mRNA stability. Besides, we describe that FASTKD3 is required for efficient COX1 mRNA translation without altering mRNA levels, which results in a decrease in the steady-state levels of COX1 protein. This finding is associated with reduced mitochondrial complex IV assembly and activity. Our observations suggest that the function of this family of proteins goes beyond RNA processing and ribosome assembly and includes RNA stability and translation regulation within mitochondria., Junta de Castilla y León (grants BIO/ VA20/15 and BIO/VA21/15), Swiss National Science Foundation (grant 310030B_160257/1)

Producción Científica, The Fas-activated serine/threonine kinase (FASTK) family of proteins has recently emerged as a central regulator of mitochondrial gene expression through the function of an unusual RNA-binding domain named RAP (for RNA-binding domain abundant in Apicomplexans), shared by all six members of the family. Here we describe the role of one of the less characterized members, FASTKD3, in mitochondrial RNA metabolism. First, we show that, in contrast to FASTK, FASTKD2, and FASTKD5, FASTKD3 does not localize in mitochondrial RNA granules, which are sites of processing and maturation of mtRNAs and ribosome biogenesis. Second, we generated FASTKD3 homozygous knock-out cell lines by homologous recombination and observed that the absence of FASTKD3 resulted in increased steady-state levels and half-lives of a subset of mature mitochondrial mRNAs: ND2, ND3, CYTB, COX2, and ATP8/6. No aberrant processing of RNA precursors was observed. Rescue experiments demonstrated that RAP domain is required for FASTKD3 function in mRNA stability. Besides, we describe that FASTKD3 is required for efficient COX1 mRNA translation without altering mRNA levels, which results in a decrease in the steady-state levels of COX1 protein. This finding is associated with reduced mitochondrial complex IV assembly and activity. Our observations suggest that the function of this family of proteins goes beyond RNA processing and ribosome assembly and includes RNA stability and translation regulation within mitochondria., Junta de Castilla y León (grants BIO/ VA20/15 and BIO/VA21/15), Swiss National Science Foundation (grant 310030B_160257/1)

The FASTK family of proteins has recently emerged as a central regulator of mitochondrial gene expression through the function of an unusual RNA-binding domains named RAP, shared by all six members of the family. Here we describe the role of one of the less characterized members, FASTKD3, in mitochondrial RNA metabolism. First, we show that, in contrast to FASTK, FASTKD2 and FASTKD5, FASTKD3 does not localize in mitochondrial RNA granules, which are sites of processing and maturation of mtRNAs and ribosome biogenesis. Second, we generated FASTKD3 homozygous knockout cell lines by homologous recombination and observed that the absence of FASTKD3 resulted in increased steady-state levels and half-lives of a subset of mature mitochondrial mRNAs: ND2, ND3, CYTB, COX2 and ATP8/6. No aberrant processing of RNA precursors was observed. Rescue experiments demonstrated that RAP domain is required for FASTKD3 function in mRNA stability. Besides, we describe that FASTKD3 is required for efficient COX1 mRNA translation without altering mRNA levels, which results in a decrease in the steady-state levels of COX1 protein. This finding is associated with reduced mitochondrial complex IV assembly and activity. Our observations suggest that the function of this family of proteins goes beyond RNA processing and ribosome assembly and includes RNA stability and translation regulation within mitochondria.

While climate change takes place world-wide, the Artic regions are very sensitive to these changes while influencing the biodiversity of the whole world. Therefore, climate archives are considered to better understand the climate of the past. In permafrost regions, covering about 24% of the northern hemisphere land surface, established climate archives such as ice caps, deep lake sediments or tree rings are rarely found. On the other hand, the ground ice contained in permafrost soils is expected to provide paleoclimatic information. Ice wedges, vertically-foliated or –banded wedge-shaped ice bodies, are considered the most appropriate type of ground ice for climate reconstructions. They form mainly by the penetration and refreezing of snow melt water in open frost cracks in early spring, resulting in annual layers which are expected to contain the temperature signal of the year of their formation. To understand the paleoclimatic signal preserved in the climate archive “ice wedge”, it is necessary to identify its source. For this purpose, a study on the spatial and temporal variability of the thickness and the isotopic composition of a snow cover during spring was carried out at Samoylov Island within the Lena Delta. Snow samples were collected at different geomorphologic units of different ice-wedge polygons and at a snow field and their isotopic composition has been correlated with weather data from Samoylov Island in order to identify annual cycles and predominant alteration processes. It was difficult to characterize an annual cycle while it was possible to identify a late warm phase in late autumn and a late cold phase in early spring. It was observed that that the snow cover and its isotopic composition undergo changes over time due to sublimation, evaporation and wind drift processes. Percolating rain water highly reduced the thickness of the snow cover but had no significant influence on its isotopic composition, while the collection of initial-snow-melt-runo

While climate change takes place world-wide, the Artic regions are very sensitive to these changes while influencing the biodiversity of the whole world. Therefore, climate archives are considered to better understand the climate of the past. In permafrost regions, covering about 24% of the northern hemisphere land surface, established climate archives such as ice caps, deep lake sediments or tree rings are rarely found. On the other hand, the ground ice contained in permafrost soils is expected to provide paleoclimatic information. Ice wedges, vertically-foliated or –banded wedge-shaped ice bodies, are considered the most appropriate type of ground ice for climate reconstructions. They form mainly by the penetration and refreezing of snow melt water in open frost cracks in early spring, resulting in annual layers which are expected to contain the temperature signal of the year of their formation. To understand the paleoclimatic signal preserved in the climate archive “ice wedge”, it is necessary to identify its source. For this purpose, a study on the spatial and temporal variability of the thickness and the isotopic composition of a snow cover during spring was carried out at Samoylov Island within the Lena Delta. Snow samples were collected at different geomorphologic units of different ice-wedge polygons and at a snow field and their isotopic composition has been correlated with weather data from Samoylov Island in order to identify annual cycles and predominant alteration processes. It was difficult to characterize an annual cycle while it was possible to identify a late warm phase in late autumn and a late cold phase in early spring. It was observed that that the snow cover and its isotopic composition undergo changes over time due to sublimation, evaporation and wind drift processes. Percolating rain water highly reduced the thickness of the snow cover but had no significant influence on its isotopic composition, while the collection of initial-snow-melt-runo