In the thick ascending loop, 

Luminal membrane contains a three-ion cotransporter  known as Na+-K+-2Cl- cotransporter

TLS Online TPP Program

#Id: 2897

#Unit 3. Fundamental Processes

The origin of the replication region remains attached to the membrane for about one-third of the cell cycle as another part of the mechanism to prevent reinitiation.

TLS Online TPP Program

#Id: 2899

#Unit 3. Fundamental Processes

Opening oriC involves action at two types of sequence in the origin: 9-bp and 13 -bp repeats.

TLS Online TPP Program

#Id: 2903

#Unit 3. Fundamental Processes

The four 9-bp consensus sequences on the right side of oriC provide the initial binding sites for DnaA-ATP in an extended multimeric state promoted by the accessory protein DiaA, which stimulates cooperative binding of DnaA.

TLS Online TPP Program

#Id: 2904

#Unit 3. Fundamental Processes

DnaA-ATP binds cooperatively to form a helical central core around which oriC DNA is wrapped.

TLS Online TPP Program

#Id: 2905

#Unit 3. Fundamental Processes

DnaA then acts at three A-T-rich 13 -bp tandem repeats located on the left side of oriC

TLS Online TPP Program

#Id: 2906

#Unit 3. Fundamental Processes

Two to four monomers of Dna AA TP bind at the origin, and after release of DiaA, they recruit two "pre-priming" complexes of the DnaB helicase bound to DnaC-ATP, so that there is one DnaB-DnaC-ATP complex for each of the two (bidirectional) replication forks.