MOLECULAR AND BEHAVIORAL-ANALYSIS OF 4 PERIOD MUTANTS IN DROSOPHILA-MELANOGASTER ENCOMPASSING EXTREME SHORT, NOVEL LONG, AND UNORTHODOX ARRHYTHMIC TYPES

Of the mutationally defined rhythm genes in Drosophila melanogaster, p eriod (per) has been studied the most. We have molecularly characteriz ed three older per mutants-per(T), per(Clk), and per(04)-along with a novel long-period one (per(SLIH)) Each mutant is the result of a Singl e nucleotide change. per(T), per(Clk), and per(SLIH) are accounted for by amino acid substitutions; per(04) is altered at a splice site acce ptor and causes aberrant splicing, per(SLIH) exhibits a long period of 27 hr in constant darkness and entrains to light/dark (L/D) cycles wi th a later-than-normal evening peak of locomotion, per(SLIH) males are more rhythmic than females. per(SLIH)'s clock runs faster at higher t emperatures and slower at lower ones, exhibiting a temperature-compens ation defect opposite to that of per(Long). The per-encoded protein (P ER) in the per(T) mutant cycles in L/D with an earlier-than-normal pea k; this peak in per(SLIH) is later than normal, and there was a slight difference in the PER timecourse of males vs, females. PER in per(04) was undetectable. Two of these mutations, per(SLIH) and per(Clk), lie within regions of PER that have not been studied previously and may d efine important functional domains of this clock protein.