Chloroplasts and mitochondria contain a family of putative preprotein and amino acid transporters designated PRAT. Here, we analyzed the role of two previously characterized PRAT protein family members, encoded by At3...Chloroplasts and mitochondria contain a family of putative preprotein and amino acid transporters designated PRAT. Here, we analyzed the role of two previously characterized PRAT protein family members, encoded by At3g49560 （HP30） and At5g24650 （HP30-2）, in planta using a combination of genetic, cell biological and biochemical approaches. Expression studies and green fluorescent protein tagging identified HP30-2 both in chloroplasts and mitochondria, whereas HP30 was located exclusively in chloroplasts. Biochemical evidence was obtained for an association of mitochondrial HP30-2 with two distinct protein complexes, one containing the inner membrane translocase TIM22 and the other containing an alternative NAD（P）H dehydrogenase subunit （NDCI） implicated in a respiratory complex 1-1ike electron trans- port chain. Through its association with TIM22, HP30-2 is involved in the uptake of carrier proteins and other, hydrophobic membrane proteins lacking cleavable N H2-terminal presequences, whereas HP30-2＇s interaction with NDC1 may permit controlling mitochondrial biogenesis and activity.展开更多
We investigated the compositional and structural differences in sequences derived from different fractions of wheat genomic DNA obtained using methylation filtration and Cot fractionation. Comparative analysis of thes...We investigated the compositional and structural differences in sequences derived from different fractions of wheat genomic DNA obtained using methylation filtration and Cot fractionation. Comparative analysis of these sequences revealed large compositional and structural variations in terms of GC content, different structural elements including repeat sequences （e.g., transposable elements and simple sequence repeats）, protein coding genes, and non-coding RNA genes. A correlation between methylation status [determined on the basis of selective inclusion/ exclusion in methylation-filtered （MF） library] of different repeat elements and expression level was observed. The expression levels were determined by comparing MF sequences with expressed sequence tags （ESTs） available in the public domain. Only a limited overlap among ME high Cot （HC）, and ESTs was observed, suggesting that these sequences may largely either represent the low-copy non-transcribed sequences or include genes with low expression levels. Thus, these results indicated a need to study MF and HC sequences along with ESTs to fully appreciate complexity of wheat gene space.展开更多
基金supported by the Chaire d’Excellence Program of the French Ministry of National Education and Research(to CR)
文摘Chloroplasts and mitochondria contain a family of putative preprotein and amino acid transporters designated PRAT. Here, we analyzed the role of two previously characterized PRAT protein family members, encoded by At3g49560 （HP30） and At5g24650 （HP30-2）, in planta using a combination of genetic, cell biological and biochemical approaches. Expression studies and green fluorescent protein tagging identified HP30-2 both in chloroplasts and mitochondria, whereas HP30 was located exclusively in chloroplasts. Biochemical evidence was obtained for an association of mitochondrial HP30-2 with two distinct protein complexes, one containing the inner membrane translocase TIM22 and the other containing an alternative NAD（P）H dehydrogenase subunit （NDCI） implicated in a respiratory complex 1-1ike electron trans- port chain. Through its association with TIM22, HP30-2 is involved in the uptake of carrier proteins and other, hydrophobic membrane proteins lacking cleavable N H2-terminal presequences, whereas HP30-2＇s interaction with NDC1 may permit controlling mitochondrial biogenesis and activity.
基金supported by the Government of India's Departments of Biotechnology,and Science and Technology, Indian National Science Academy,and National Institute of Health grant(No.1 R01 GM080749-01A1)
文摘We investigated the compositional and structural differences in sequences derived from different fractions of wheat genomic DNA obtained using methylation filtration and Cot fractionation. Comparative analysis of these sequences revealed large compositional and structural variations in terms of GC content, different structural elements including repeat sequences （e.g., transposable elements and simple sequence repeats）, protein coding genes, and non-coding RNA genes. A correlation between methylation status [determined on the basis of selective inclusion/ exclusion in methylation-filtered （MF） library] of different repeat elements and expression level was observed. The expression levels were determined by comparing MF sequences with expressed sequence tags （ESTs） available in the public domain. Only a limited overlap among ME high Cot （HC）, and ESTs was observed, suggesting that these sequences may largely either represent the low-copy non-transcribed sequences or include genes with low expression levels. Thus, these results indicated a need to study MF and HC sequences along with ESTs to fully appreciate complexity of wheat gene space.
