دانلود ترجمه مقاله گذر از تکثیر به تمایز در ریشه با کنترل های تنظیم رونوشتی ROS – نشریه CellPress

• فهرست مطالب:

خلاصه
مقدمه
نتایج
پروتئین UPB1 ظاهرا از کلاهک ریشۀ جانبی به منطقۀ ازدیاد طول حرکت میکند
شناسایی ژن های تنظیم شده توسط UPB1
شناسایی اهداف مستقیم UPB1
فرآیندهای اکسایشی کاهشی برای تنظیم رشد ریشه اهمیت دارند
بحث
توزیع ROS برای گذر از تکثر به تفکیک در گیاهان و حیوانات اهمیت دارد
تنظیم UPB1 رشد ریشه از مسیر نشانه دهی اکسین/سیتوکینن جدا میباشد
UPB1 ممکن است بدون سلول مستقل عمل کند
رویه های آزمایشی
مواد گیاهی و درمان
آزمایشات ریزآرایه
آزمایش ChIP-chip
تیمارهای هورمون گیاهی و مربوط به ROS

• بخشی از ترجمه:

UPB1 به منظور کنترل گذر از تکثیر به تفکیک ،نشانه دهی ROS راکنترل می کند
تجزیه و تحلیل بیان ریزآرایه ایی ما به همراه آنالیز UPB1 ChIPchip نشان داد که UPB1 مجموعه ایی از پراکسیدازها را در هنگامی که سلول شروع به تفکیک می کند ،مستقیما سرکوب می کند.استفاده از بازدارنده های شیمیایی و بیان نابجای یکی از ژن های پراکسیداز هدف(Per57)، همچنین شناساگرهای شیمیایی برای ROS شواهد مستدل در مورد کنترل توزیع ROS توسط این پراکسیدازها در اختیار ماقرار میدهند که این به نوبۀ خود گذر از تکثیر به تفکیک را مهار می کند. تیمار با بازدارنده های پراکسیداز که باعث کاهش اندازۀ مریستم ریشه می شوند ونشانگر آغاز زودهنگام تفکیک است بر این مطلب صحه میگذارد(شکل 5K).
این مطالعات ژنتیکی و شیمیایی ، اهمیت فعالیت پراکسیداز در نوک ریشه را آشکار می کند وباتعبیر ما در مورد ارتباط مستقیم فنوتیپ upb1-1 باتنظیم UPB1 حداقل در سه پراکسیداز دستۀ III همخوانی و مطابقت دارد. در آرابیدوپسیس 73 ژن پراکسیداز دستۀ III وجود دارد(Tognolli و همکاران 2002) که 60 تای آنها در آرایۀ ATH1 نمایان میشوند و 21 مورد تحت تأثیر UPB1 هستند. هر 21 ژن عمدتا در ناحیۀ ازدیاد طول بیان میشوند(شکل S3).ما خطوط اتصال T-DNA تعداد زیادی از پراکسیدازها را که هدف UPB1 هستند بدست آوردیم. اما جهش یافته های سینگل(تک) فنوتیپ آشکار از خود نشان ندادند(داده ها ارائه نشده است) و این احتمال به دلیل افزونگی کارکردی است. 

• بخشی از مقاله انگلیسی:

Growth in multicellular organisms depends on maintaining the proper balance between cell division and differentiation. Disruption of this balance in animals can lead to disease states such as cancer. In plants, because organs are continuously formed from stem cells, disruption of this balance leads to premature cessation of growth or abnormal organogenesis. In the root of Arabidopsis, cells originate from a stem cell center at the tip. Progeny of these stem cells rapidly divide in a transit-amplifying zone know as the meristem, after which they undergo massive increases in cell volume in the elongation zone. The transition from cellular proliferation to elongation marks the initial stage of differentiation and occurs at a slightly different point for each cell type, producing a somewhat jagged boundary of this transition zone (TZ). Once fully elongated, cells enter the maturation zone in which they differentiate into various cell types. Previous work has shown that root growth is determined by the rate of cell division in the meristematic zone and the extent of cell expansion in the elongation zone (Beemster and Baskin, 1998). Acceleration of root growth in Arabidopsis is correlated with increasing root meristem size as a result of increased rates of cell division and the delay of the onset of cell expansion (Ubeda-Tomas et al., 2009). Several factors have been identified that are involved in the regulation of the transition from cellular proliferation to differentiation. The PLETHORA (PLT) proteins have been shown to determine the position of the stem cell niche and are required to maintain stem cell activity (Aida et al., 2004). There is also evidence that the balance between the hormones cytokinin and auxin in the TZ plays an important role in defining the size of the meristem (Dello Ioio et al., 2008). External applications of these hormones can change the position of the TZ. The underlying mechanism involves a cytokinin-dependent transcription factor, ARR1, which regulates the expression of another transcription factor, SHY2, which acts in auxin signaling (Dello Ioio et al., 2008). It is unclear whether this hormonal signaling interaction is the only means of controlling the transition from proliferation to differentiation. Evidence for another pathway acting to maintain meristem function came from studies of the ROOT MERISTEMLESS1 (RML1) gene. Mutations in this gene result in plants that are not able to establish an active root meristem. RML1 encodes a glutathione biosynthetic enzyme, which has been shown to be important for regulating cellular redox states. Furthermore, it was shown that the G1-to-S cell-cycle transition in synchronized tobacco cell suspension culture required an adequate level of glutathione (Vernoux et al., 2000). These results suggested that redox regulation plays an important role in maintaining root meristem activity. Moreover, this is supported by the finding that differences in superoxide and hydrogen peroxide accumulation in the root tip significantly affect root growth and differentiation (Dunand et al., 2007). In animals, there are numerous studies indicating that reactive oxygen species (ROS) distribution plays an important role in regulating cell state decisions (Owusu-Ansah and Banerjee, 2009; Sarsour et al., 2008). However, no molecular link between ROS distribution and cell status has been previously established at the transcriptional level in either plants or animals. Here, we show that a bHLH transcription factor, UPBEAT1 (UPB1), modulates the balance between cell proliferation and differentiation by directly regulating the expression of a set of peroxidases. Peroxidases are known to regulate the levels of certain ROS, particularly hydrogen peroxide and superoxide. Staining for the presence of these ROS in the root and altering their concentrations using chemical reagents showed a clear correlation between growth rate, location of the TZ, and the relative distribution of different ROS species in the meristematic and elongation zones. Interestingly, differences in the localization of UPB1 in transcriptional and translational reporter lines suggest that this transcriptional regulator might also function as an intercellular signaling molecule. We show evidence that UPB1 provides a direct transcriptional link between ROS distribution and the proliferation status of the cells in the root tip. RESULTS UPBEAT1 Controls the Transition from Cellular Proliferation to Differentiation To identify transcription factors (TFs) that regulate the first stages of the transition from cellular proliferation to differentiation, we Figure 1. Features of the upbeat1 (upb1) Mutant (A) Wild-type Col-0, upb1-1, and 35S::UPB1-3YFP seedlings 5 days after imbibition (dai). (B) Average root length (y axis) of 50 individuals of Col-0 (blue), upb1-1 (red), and 3 independent 35S::UPB1-3YFP (green, purple, and light blue) lines. Measurements were taken over several days (x axis). Error bars depict standard deviation (SD). (C) Genomic structure of At2g47270 and position of the T-DNA insertion of upb1-1 and upb1-2 mutants. The predicted protein is depicted below. Gray shaded box shows basic helix-loop-helix domain (bHLH). (D) Root tip morphology of 6 dai Col-0, upb1-1, and 35S::UPB1-3YFP (line #2) plants.

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