Prior to transfer to a nascent chain in the lumen of the  ER, the oligosaccharide precursor is assembled on amembrane- attached anchor called dolichol phosphate, a longchain polyisoprenoid lipid

TLS Online TPP Program

#Id: 8847

#Section 3: Genetics, Cellular and Molecular Biology

When CDK activity is low= helicases are loaded in G1

When CDK activity is high= helicases are activated in

S, G2 & M

TLS Online TPP Program

#Id: 8848

#Section 3: Genetics, Cellular and Molecular Biology

TLS Online TPP Program

#Id: 8849

#Section 3: Genetics, Cellular and Molecular Biology

Phosphorylation of MCM helicase activators by G1/S phase CDKs and S phase CDKs, prevents reloading of MCM helicases (ensuring that replication from each origin occurs only once during each cell cycle)

TLS Online TPP Program

#Id: 8850

#Section 3: Genetics, Cellular and Molecular Biology

Geminin 

a small protein,, that contributes to the inhibition of re-initiation at origins until cells complete a full cell cycle.

TLS Online TPP Program

#Id: 8851

#Section 3: Genetics, Cellular and Molecular Biology

Geminin is expressed in late G1; it binds to and inhibits Cdt1 preventing reloading of the MCM helicase.

TLS Online TPP Program

#Id: 8852

#Section 3: Genetics, Cellular and Molecular Biology

Geminin contains a destruction box at its N-terminus that is recognized by APC/Ccdh1, causing it to be ubiquitinylated in late anaphase and degraded by proteasomes.