These cells wall off the organism inside a granuloma called a tubercle. The localized concentrations of lysosomal enzymes in these granulomas can cause extensive tissue necrosis.

TLS Online TPP Program

#Id: 2400

#Unit 3. Fundamental Processes

Sigma Region 3/4 linker mimics RNA

TLS Online TPP Program

#Id: 2401

#Unit 3. Fundamental Processes

Region ¾ linker of s lies in the middle of the RNA exit channel in the open complex

TLS Online TPP Program

#Id: 2402

#Unit 3. Fundamental Processes

TF11S displays little similarity in sequence or structure to the Gre factors, but it binds to the same part of the enzyme, the RNA polymerase secondary channel (pore). 

TLS Online TPP Program

#Id: 2403

#Unit 3. Fundamental Processes

The cleavage activity is intrinsic to RNA polymerase itself, it is stimulated greatly by accessory factors that are ubiquitous in the three biological kingdoms. There are two such factors in E. coli, GreA and GreB, and eukaryotic RNA polymerase II uses TFIIS for the same purpose. 

TLS Online TPP Program

#Id: 2404

#Unit 3. Fundamental Processes

The Gre factors/TF11S enable the polymerase to cleave a few ribonucleotides from the 3' terminus of the RNA product, thereby allowing the catalytic site of RNA polymerase to be realigned with the 3' -OH.

TLS Online TPP Program

#Id: 2405

#Unit 3. Fundamental Processes

An arrested RNA polymerase can restart transcription by cleaving the RNA transcript to generate a new 3' end.