ID   PER_SYRPI               Reviewed;         109 AA.
AC   Q26612;
DT   15-JUL-1999, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1996, sequence version 1.
DT   25-MAY-2022, entry version 46.
DE   RecName: Full=Period circadian protein;
DE   Flags: Fragment;
GN   Name=per;
OS   Syritta pipiens (Hoverfly).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Hexapoda; Insecta; Pterygota;
OC   Neoptera; Endopterygota; Diptera; Brachycera; Muscomorpha; Syrphoidea;
OC   Syrphidae; Eristalinae; Xylotini; Syritta.
OX   NCBI_TaxID=34682;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=7815924; DOI=10.1093/oxfordjournals.molbev.a040167;
RA   Nielsen J., Peixoto A.A., Piccin A., Costa R., Kyriacou C.P., Chalmers D.;
RT   "Big flies, small repeats: the 'Thr-Gly' region of the period gene in
RT   Diptera.";
RL   Mol. Biol. Evol. 11:839-853(1994).
CC   -!- FUNCTION: Essential for biological clock functions. Determines the
CC       period length of circadian and ultradian rhythms; an increase in PER
CC       dosage leads to shortened circadian rhythms and a decrease leads to
CC       lengthened circadian rhythms. Essential for the circadian rhythmicity
CC       of locomotor activity, eclosion behavior, and for the rhythmic
CC       component of the male courtship song that originates in the thoracic
CC       nervous system. The biological cycle depends on the rhythmic formation
CC       and nuclear localization of the TIM-PER complex. Light induces the
CC       degradation of TIM, which promotes elimination of PER. Nuclear activity
CC       of the heterodimer coordinatively regulates PER and TIM transcription
CC       through a negative feedback loop. Behaves as a negative element in
CC       circadian transcriptional loop. Does not appear to bind DNA, suggesting
CC       indirect transcriptional inhibition (By similarity). {ECO:0000250}.
CC   -!- SUBUNIT: Forms a heterodimer with timeless (TIM); the complex then
CC       translocates into the nucleus. {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: Nucleus {ECO:0000250}. Cytoplasm, perinuclear
CC       region {ECO:0000250}. Note=Nuclear at specific periods of the day.
CC       First accumulates in the perinuclear region about one hour before
CC       translocation into the nucleus. Interaction with Tim is required for
CC       nuclear localization (By similarity). {ECO:0000250}.
CC   -!- PTM: Phosphorylated with a circadian rhythmicity, probably by the
CC       double-time protein (dbt). Phosphorylation could be implicated in the
CC       stability of per monomer and in the formation of heterodimer per-tim
CC       (By similarity). {ECO:0000250}.
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DR   EMBL; U11804; AAA76596.1; -; Genomic_DNA.
DR   AlphaFoldDB; Q26612; -.
DR   GO; GO:0005634; C:nucleus; IEA:UniProtKB-SubCell.
DR   GO; GO:0048471; C:perinuclear region of cytoplasm; IEA:UniProtKB-SubCell.
DR   GO; GO:0048511; P:rhythmic process; IEA:UniProtKB-KW.
PE   3: Inferred from homology;
KW   Biological rhythms; Cytoplasm; Nucleus; Phosphoprotein; Repeat.
FT   CHAIN           <1..>109
FT                   /note="Period circadian protein"
FT                   /id="PRO_0000162625"
FT   REGION          59..109
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        59..102
FT                   /note="Polar residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   NON_TER         1
FT   NON_TER         109
SQ   SEQUENCE   109 AA;  11525 MW;  8601335D822493DC CRC64;
     SKSSTETPPS YNQLNYNENL QRFFNSKPAT APVEFDPIKM DQSYNEPAEA ECTVSPVQCF
     EGSGGSGSSG NFTSGSNLNM RSVTNTSNTG TGTSSESVPL VTLTEALIS