A comparative study of the clock gene period in Blattella bisignata and B. germanica
Date Issued
2005
Date
2005
Author(s)
Wu, Chia-Eng
DOI
en-US
Abstract
Circadian rhythms are nearly 24-hour rhythms of biological processes that persist under constant environmental conditions. These rhythms have been described in a variety of organisms ranging from prokaryotes to mammals. In Drosophila, the driving force underlying the circadian system is the pacemaker cells with time signal generated by the interactions of the negative feedback loop of period and timeless genes. In several other insect species, including the German cockroach, per expression undergoes circadian fluctuations. Oddly, the overt rhythm of locomotion of female German cockroach is masked by its own reproductive cycle. We suspect that clocks in peripheral tissues, especially in reproductive organs, may affect the brain-clock (master clock) which has been demonstrated to control the locomotor circadian rhythm. However, the Blattella bisignata, a closely-related species of the B. germanica, expresses locomotor circadian rhythm without masking effect in both sexes. This study focuses on the expression of per in brain and reproductive tissues in both species to unveil the possible interaction of clock gene expression under masking effect of locomotor circadian rhythm. Period gene in the double-striped cockroach has been cloned and its partial sequence shows a high degree of homology with the one from the German cockroach. Furthermore, the expression patterns of period mRNA were similar in heads and reproductive tissues, which were peaked at night. The exceptions in expression patterns of testes of German cockroach and ovaries of both species suggest that different regulatory clock mechanisms maybe involved.
Subjects
時鐘基因
clock gene period
Type
thesis
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