In the nucleus, the cap is recognized and bound by the cap binding CBP20/80 heterodimer. This binding event stimulates splicing of the first intron and, via a direct interaction with the mRNA export machinery (TREX complex), facilitates mRNA export out of the nucleus. Once reaching the cytoplasm, a different set of proteins (eIF4F) binds the cap to initiate translation of the mRNA in the cytoplasm.

TLS Online TPP Program

#Id: 6697

#Unit 3. Fundamental Processes

Wild-type HIV produces a protein called Vif (viral infectivity factor) that directs proteosomal degradation of the A3G enzyme

TLS Online TPP Program

#Id: 6698

#Unit 3. Fundamental Processes

TLS Online TPP Program

#Id: 6699

#Unit 3. Fundamental Processes

TLS Online TPP Program

#Id: 6700

#Unit 3. Fundamental Processes

The introns in pre-tRNA vary in length from 14 to 60 bases and only single intron is found in each pre-tRNA transcript A pre-tRNA intron is excised in one step  Finally, hydrolysis of GTP and ATP is required to join the two tRNA halves generated by cleavage on either side of the intron.

TLS Online TPP Program

#Id: 6701

#Unit 3. Fundamental Processes

TLS Online TPP Program

#Id: 6702

#Unit 3. Fundamental Processes

Single intron that is located just one nucleotide beyond the 3’ side of the anticodon