Navigation Links
Stop and go
Date:2/23/2011

Gene transcription is central to cell function, as it converts the information stored in the DNA into RNA molecules of defined sequence, which then program protein synthesis. The enzyme RNA polymerase II (Pol II) is responsible for this genetic readout, but is prone to transcriptional arrest. The biochemist Professor Patrick Cramer, Director of LMU's Genzentrum, and his research associate Dr. Alan Cheung have now shown for the first time and captured on film -- what happens when Pol II arrests at a "roadblock". They were even able to observe how transcript is reactivated. Reactivation of arrested transcriptional complexes is a normal part of the readout process, and is therefore of fundamental significance in all cells. Indeed, as Patrick Cramer points out, "It is also utilized to regulate gene activity in stem and tumor cells." (Nature online, 23 February 2011)

According to Patrick Cramer, "DNA itself is a silent molecule". It takes the enzyme RNA polymerase II to bring it to life. Pol II is the molecular machine that transcribes the genetic information encoded in the DNA into molecules of messenger RNA (mRNA). These in turn act as blueprints for the synthesis of proteins, whose structures are specified by the nucleotide sequences of the mRNAs. Since proteins, which include enzymes like Pol II, carry out most functions in cells, the process of transcription is essential for life.

Transcription is highly complex and easily perturbed. Misincorporated nucleotides and other errors are quite frequent and can cause the enzyme to arrest. In such a case, Pol II often moves in retrograde, sliding a short distance in the opposite direction along the DNA, so that the defect can be repaired. As soon as such proofreading takes place, the enzyme restarts. Sometimes, however, the enzyme moves too far backwards, and the RNA it has just synthesized gets jammed in a binding pocket.

This brings the transcription process to a complete halt, and Pol II then requires the transcription factor TFIIS to get it moving again. TFIIS alters the shape of the active center of the enzyme, so that the tangled stretch of RNA can be excised, and transcription then resumes, with Pol II synthesizing that segment again. Cramer and Cheung have dissected the mechanism of blockade and reactivation in molecular detail -- and recorded it on film.

Among other insights, it emerged that TFIIS not only displaces the trapped segment of mRNA, it also facilitates its excision. "This process occurs in all cells all the time, and is essential for their survival", says Cramer. "In addition, in higher organisms, it is utilized to regulate gene activity, particularly in stem cells and tumor cells. Pol II performs a central function in cells, and is therefore the focus of my research. My approach is increasingly influenced by systems biology, and aims to elucidate the transcriptional network of the cell and describe it in molecular and mechanistic terms". (gd/suwe)


'/>"/>

Contact: Dr. Patrick Cramer
cramer@lmb.uni-muenchen.de
49-892-180-76965
Ludwig-Maximilians-Universitt Mnchen
Source:Eurekalert

Post Your Comments:
*Name:
*Comment:
*Email:
(Date:3/29/2016)... LegacyXChange, Inc. (OTC: LEGX ... Protect are pleased to announce our successful effort to ... of writing instruments, ensuring athletes signatures against counterfeiting and ... athletes on LegacyXChange will be assured of ongoing proof ... Bill Bollander , CEO states, "By inserting ...
(Date:3/21/2016)... Massachusetts , March 22, 2016 ... facial recognition with passcodes for superior security   ... ), a leading provider of secure digital communications services, ... their biometric technology and offer enterprise customers, particularly those ... secure facial recognition and voice authentication within a mobile ...
(Date:3/15/2016)... Yissum Research Development Company of the ... the Hebrew University, announced today the formation of ... various human biological indicators. Neteera Technologies has completed its ... investors. ... electromagnetic emissions from sweat ducts, enables reliable and speedy ...
Breaking Biology News(10 mins):
(Date:5/27/2016)... ... , ... Doctors in Italy, Japan, the UK and the US have reached ... gene and its link to malignant mesothelioma. Surviving Mesothelioma has just posted the details ... now. , The studies analyzed for the new report included more than 3,447 ...
(Date:5/26/2016)... , May 26, 2016  Agriculture nutrients are in ... Moines, Iowa is running their nitrate removal ... Lake Erie and coastal regions nationwide are ... preventing this widespread issue. NECi Superior Enzymes, ... Upper Peninsula, developed a new, easy to use device ...
(Date:5/26/2016)... Despite the volatility that continues to envelop the ... research on ActiveWallSt.com directs the investor community,s focus on the ... ), Cerus Corp. (NASDAQ: CERS ), Arrowhead Pharmaceuticals ... Inc. (NASDAQ: FPRX ). Register with us today ... On Wednesday, shares in Massachusetts ...
(Date:5/26/2016)... ... 26, 2016 , ... FireflySci has been manufacturing quartz and ... over the globe. Their cute firefly logo has been spreading to more and ... spectrophotometer calibration standards that never require recalibration. These revolutionary standards have changed ...
Breaking Biology Technology: