PER3

The PER3

The Per3 gene was independently cloned by two research groups (Kobe University School of Medicine and Harvard Medical School) who both published their discovery in June 1998.^[7][8] The mammalian Per3 was discovered by searching for homologous cDNA sequences to Per2. The amino acid sequence of the mouse PERIOD3 protein (mPER3) is between 37-56% similar to the other two PER proteins.^[8][7]

Function

This gene is a member of the Period family of genes. It is expressed in a

The mPER3 protein contains a PAS domain, similar to mPER1 and mPER2. Likely, mPER3 binds to other proteins using this domain.^[8] However, while PER1/2 have been shown to be important in the transcription-translation feedback loop involved in the intracellular circadian clock, the influence of PER3 in this loop has not yet been fully elucidated, given that mPER3 does not appear to be functionally redundant to mPER1 and mPER2.^[12] mPer3 may not be a member of the core clock loop at all.^[12]

Animal studies

While the Per3 gene is a

Per3 knockout mice experience a slightly shortened period of locomotor activity (by 0.5 hr^[13]) and are less sensitive to light, in that they entrain more slowly to changes in the light-dark cycle. PER3 may be involved in the suppression of behavioral activity in response to light, although mPer3 expression is not necessary for circadian rhythms.^[14][15]

Clinical significance

The PER3 “length” polymorphism in the 54-bp repeat sequence in exon 18 (GenBank accession no. AB047686) is a structural polymorphism due to an insertion or deletion of 18 amino acids in a region encoding a putative phosphorylation domain. The polymorphism has been associated with diurnal preference and

The following is a list of some orthologs of the PER3 gene in other species:^[17]

Paralogs

• PER1
• PER2

Gene location

The human PER3 gene is located on chromosome 1 at the following location:^[18]

• Start: 7,784,320 bp
• Finish: 7,845,181 bp
• Length: 60,862 bases
• Exons: 25

PER3 has 19 transcripts (splice variants).

Protein structure

The PER3 protein has been identified to have the following features:^[19]

• Size: 1201 amino acids
• Molecular mass: 131888 Da
• Quaternary structure: Homodimer

Post translational modifications

The following are some known post transcriptional modifications to the Per3 gene:^[19]

• Phosphorylation by CSNK1E is weak and appears to require association with PER1 and translocation to the nucleus.
• Ubiquitinated.
• Modification sites at PhosphoSitePlus
• Modification sites at neXtProt

References