In vitro Mitochondrial Nucleoid DNA Replication and Transcription are Affected by the Associated Mitochondrial Membrane

粒線體nucleoid DNA複製和轉錄受其相連的粒線體膜系影響

李寶林(Bao-Lin Li) ； 羅意珊(Yih-Shan Lo) ； 戴華(Hwa Dai)

《Botanical Studies》 52卷2期 (2011/04) Pp. 137-144

摘要

這項研究顯示粒線體基因複製和轉錄除受粒線體核蛋白的影響外，與粒線體nucleoid關聯的特定膜元件可能也對粒線體基因的表達發揮重要作用。粒線體nucleoids可自給自足的行粒線體基因複製和轉錄。這研究將整個粒線體以特定方式溶解後，以常規間斷蔗糖梯度離心將其依密度的不同分為七組不同的mitochondrial nucleoid-membrane complexes。這不同密度的mitochondrial nucleoid-membrane complexes含有明顯不同量的粒線體膜系。在行體外mtDNA複製和轉錄結果中，我們確定不同粒線體的複製和轉錄的能力深受粒線體的膜系含量影響。我們因而確認粒線體基因的表達受粒線體DNA，粒線體核蛋白和粒線體膜系間的相關結構，組合關係密切。

關鍵字

線粒體膜系 ； Mitochondrial nucleoid-membrane complex ； 線粒體nucleoids ； 線粒體基因複製 ； 線粒體基因轉錄 ； 綠豆

並列摘要

Fractionation of lysed mitochondria of mung bean seedlings by discontinuous sucrose gradient centrifugation resulted in three major and two minor fractions of mitochondrial nucleoid-membrane complexes based on their sedimentation density. Noticeably different quantities of mitochondrial membrane were found to associate with the different mitochondrial nucleoid fractions, suggesting that mitochondrial DNA, mtDNA binding proteins and membrane may be constituted in a heterogeneous organization among those fractions and result in different sizes, shapes and densities. Moreover, mitochondrial nucleoid-membrane complexes from these five fractions displayed differential abilities of in vitro DNA replication/synthesis and transcription. This implies, for the first time, that some biological activities such as DNA replication/ synthesis or gene transcription of the mitochondrial nucleoids can be affected by the specific membranes associated with them.

並列關鍵字

Mitochondrial membrane ； Mitochondrial nucleoid-membrane complex ； Mitochondrial nucleoids ； mtDNA replication ； mtDNA transcription ； Mung bean