Question

RNA pol III is controlled by three factors (complexes). Two are called "Assembly Factors", and the other is a true "Initiation Factor". The Initiation Factor directly specifies the startpoint for transcription. Which complexes are designated as "Assembly Factors"?

A. TFIIIA and TFIIIB
B. TFIIIA and TFIIIC
C. TFIIIB and TFIIIC
D. UBF1 and SL1

Answer 1

B.TFIIIA and TFIIIC

Step-by-step explanation:

Kassavetis et al (1990) showed that the TFIIIA and TFIIIC are assembly factors. In their work, the authors discovered in S. cerevisiae that TFIIIB binds to the DNA upstream of the transcription start site, in a manner-dependent of TFIIIC activity . This work was published in the prestigious Cell journal: "G.A., Braun,B.R., Nguyen,L.H. and Geiduschek,E.P. (1990) S. cerevisiae TFIIIB is the transcription initiation factor proper of RNA polymerase III, while TFIIIA and TFIIIC are assembly factors. Cell, 60, 235–245"

Answer 2

Option B

Step-by-step explanation:

IIITFIIIA and TFIIIC are assembly factors, while TFIIIB is the transcription initiation factor proper of RNA polymerase .TFIIIC acts as an assembly factor that positions TFIIIB to bind to DNA at a site centered approximately 26 base pairs.