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Full-Text Articles in Medical Biochemistry
Circadian Rhythmicity By Autocatalysis, Arun Mehra, Christian I. Hong, Mi Shi, Jennifer J. Loros, Jay C. Dunlap, Peter Ruoff
Circadian Rhythmicity By Autocatalysis, Arun Mehra, Christian I. Hong, Mi Shi, Jennifer J. Loros, Jay C. Dunlap, Peter Ruoff
Dartmouth Scholarship
The temperature compensated in vitro oscillation of cyanobacterial KaiC phosphorylation, the first example of a thermodynamically closed system showing circadian rhythmicity, only involves the three Kai proteins (KaiA, KaiB, and KaiC) and ATP. In this paper, we describe a model in which the KaiA- and KaiB-assisted autocatalytic phosphorylation and dephosphorylation of KaiC are the source for circadian rhythmicity. This model, based upon autocatalysis instead of transcription-translation negative feedback, shows temperature-compensated circadian limit-cycle oscillations with KaiC phosphorylation profiles and has period lengths and rate constant values that are consistent with experimental observations.
Patterns Of Polyadenylation Site Selection In Gene Constructs Containing Multiple Polyadenylation Signals., Roger Denome, Charles Cole
Patterns Of Polyadenylation Site Selection In Gene Constructs Containing Multiple Polyadenylation Signals., Roger Denome, Charles Cole
Dartmouth Scholarship
We have constructed a series of plasmids containing multiple polyadenylation signals downstream of the herpes simplex virus type 1 (HSV) thymidine kinase (tk)-coding region. The signals used were from the simian virus 40 (SV40) late gene, the HSV tk gene, and an AATAAA-containing segment of the SV40 early region. This last fragment signals polyadenylation poorly in our constructs and not at all during SV40 infection. All plasmids contained the SV40 origin of replication. Plasmids were transfected into Cos-1 cells; after 48 h, cytoplasmic RNA was isolated and the quantity and 3'-end structure of tk mRNAs was analyzed by using S1 …