Embryonic cells, germ-line cells, and stem cells produce telomerase, but most human somatic cells produce only a small amount of telomerase as they enter S phase.

TLS Online TPP Program

#Id: 6707

#Unit 3. Fundamental Processes

Cajal bodies are centers of RNP-complex assembly for spliceosomal snRNPs and other RNPs

TLS Online TPP Program

#Id: 6708

#Unit 3. Fundamental Processes

Conversion of specific uridine residues to pseudouridine and the addition of methyl groups to the 2′-hydroxyl groups

of specific riboses, that are important for the proper assembly and function of snRNPs in pre-mRNA splicing. 

These modifications occur in Cajal bodies, where they are directed by a class of snoRNA-like guide RNA molecules called scaRNAs (small Cajal body–associated RNAs)

TLS Online TPP Program

#Id: 6709

#Unit 3. Fundamental Processes

Cajal bodies are sites of reassembly of the U4/U6/U5 tri-snRNP complex from the free U4, U5, and U6 snRNPs released during the removal of introns from mRNAs

TLS Online TPP Program

#Id: 6710

#Unit 3. Fundamental Processes

p53 tumor suppressor protein appears to be post-translationally modified by phosphorylation and acetylation in PML nuclear bodies

TLS Online TPP Program

#Id: 6711

#Unit 3. Fundamental Processes

PML nuclear bodies are also sites of post-translational modification of proteins through the addition of a small, ubiquitin-like protein called SUMO1

TLS Online TPP Program

#Id: 6712

#Unit 3. Fundamental Processes