Meeting Abstract

P3-26   -   Circadian gene expression across reproductive phases in the green anole lizard (Anolis carolinensis) brain Grossen, TL; Bunnam, AD*; Cohen, RE; Minnesota State University, Mankato; Minnesota State University, Mankato; Minnesota State University, Mankato Taylor.Grossen@mnsu.edu

Seasonal reproduction is associated with dramatic changes in reproduction, such as increased gonadal steroid hormone production, changes in brain structure and increased reproductive behavior in the breeding compared to the non-breeding season. This annual pattern is largely regulated by changing environmental conditions, similar to the circadian rhythm system that regulates daily patterns. Several genes are responsible for creating the circadian rhythm and might also regulate annual rhythms, including PER1, CIART1, CLOCK, BMAL and CRY. For example, studies in seasonally breeding rodents have suggested that several circadian clock genes, including PER1, are differentially expressed across seasons. However, it is not known if the circadian system might regulate seasonal changes across vertebrates. To begin to address this, we examined the expression of several circadian genes in the hypothalamus of the seasonally breeding green anole lizard (Anolis carolinensis). Preliminary RNA-seq studies in male anole lizards (n = 3) revealed that PER1 and CIART1 might be upregulated in the breeding season. To confirm this observation, we performed quantitative real-time PCR on RNA isolated from the hypothalamus of breeding and non-breeding male and female anole lizards. We found no effects of season (F1,19 = 0.81, p = 0.379, n =10) or sex (F1,19 = 0.08, p = 0.778, n = 10) on PER1 mRNA expression, suggesting that PER1 levels are not altered seasonally in the anole. We are currently examining CIART1 mRNA expression and are planning to continue analyzing the hypothalamic expression of other circadian rhythm products, including CLOCK, BMAL, and CRY. Understanding how the circadian clock is regulated seasonally in anoles may reveal a potential relationship between seasonal reproduction and the circadian rhythm system in reptiles.