This yielded an interaction map that contains 5560 interactions among 3725 proteins, an average of three interactions per protein.

PER protein in this mutant is hypophosphorylated.

There are three RNA nucleotides per protein monomer.

They documented the molecular weight, isoelectric point, optical absorption spectra and presence of two iron atoms per protein molecule.

Cyc is a recessive mutant, characterized by a severe reduction in levels of PER protein.

They found that PER protein levels fluctuate in light dark cycles, and these fluctuations persist in constant darkness.

Young suspected that this protein postponed the intercellular accumulation of PER protein by destroying it.

It has been shown in Drosophila that phosphorylation of the PER proteins increase their ubiquitination, which leads to degradation.

Phosphorylation of the PER proteins also leaves them unable to enter the nucleus, where they suppress transcription of clock genes.

This sequence motif is found in between six and eight copies per protein which fold together to form a larger circular solenoid structure called a beta-propeller domain.

While type I domains are usually found in multiple copies within proteins, the type II are typically found in a single copy per protein.

Per- The per gene is a clock gene that encodes for the PER protein in Drosophila.

The innate response peptide could be a silver bullet, assuming there is only one of these per protein and only a few genome loci with the protein.

Thus, in dbt mutants, PER proteins were not phosphorylated by DBT protein.

However, this CK1ε-mediated constraint to the cytoplasm can be overcome when the PER protein complex is bound to CRY.

Per mRNA levels peaked at the beginning of the subjective night followed by a peak in PER protein levels about 6 hours later.

TIM binds to the PER protein to create a heterodimer whose transcription-translation feedback loop controls the periodocity and phase of the circadian rhythms.

The results indicated that the tau mutation was actually a gain-of-function mutation, instead of loss-of-function, that caused the more rapid degradation of the PER proteins.

However, SIRT1's role is still controversial and it may also have a role in deacetylating PER protein, targeting it for degradation.

Young's team later cloned the dbt gene and found that the DBT protein was a kinase which specifically phosphorylated PER proteins.

In 1998, it was discovered that per produces two transcripts (differing only by the alternative splicing of a single untranslated intron) which both encode the PER protein.

In 1992 Benzer, working with Michael Rosbash, furthered this work by showing that the PER protein, which period codes for, is predominantly located in the nucleus.

DBT, a kinase that phosphorylates PER protein, regulates the molecularly-driven, biological clock controlling circadian rhythm in Drosophila.

In light-dark cycles, TIM protein level decreases rapidly in late night/early morning, followed by the similar but more gradual changes in PER protein level.

In fact, these mutants expressed even higher cytosolic levels of PER than cells in which PER protein was associated with TIM protein.