In an unperturbed embryo, both ABa and ABp contact the EMS blastomere, but only ABp contacts the P2 cell.

TLS Online TPP Program

#Id: 2310

#Unit 3. Fundamental Processes

The transition from the closed to the open complex involves structural changes in the enzyme and the opening of the DNA double helix to reveal the template and nontemplate strands. This “melting” occurs between positions –11 and +2, with respect to the transcription start site.

TLS Online TPP Program

#Id: 2311

#Unit 3. Fundamental Processes

P-TEFb activates elongation, splicing and polyadenylation and phosphorylates

  Serine 2 CTD

  TAT-SF1

  SPT5

TLS Online TPP Program

#Id: 2312

#Unit 3. Fundamental Processes

Ser2 phosphatase Fcp1 regenerates RNA Pol II pool

TLS Online TPP Program

#Id: 2313

#Unit 3. Fundamental Processes

Splicing is an SN2 reaction that proceeds through a pentavalent phosphorous intermediate.

TLS Online TPP Program

#Id: 2314

#Unit 3. Fundamental Processes

There are three type of Splicing Machinery

 

TLS Online TPP Program

#Id: 2315

#Unit 3. Fundamental Processes

The group I and group II introns have the remarkable ability to excise themselves from an RNA. This is called auto-splicing, or self-splicing. 

Group I introns are more common than group II introns.