Comparative genomics of heat shock proteins system in extremophile nonbiting midges

Poster (download)

128

Olga Kozlova¹, Guzel Gazizova², Elena Shagimardanova³, Oleg Gusev^4
1Kazan Federal University, olga-sphinx@yandex.ru
²Kazan Federal University, grgazizova@gmail.com
³Kazan Federal University, rjuka@mail.ru
⁴Kazan Federal University, gaijin.ru@gmail.com

Here we compare the number and expression profiles of HSP-coding genes in larvae of Chironomidae family (Diptera), who are known for their ability to successfully combat abiotic stresses using wide range of behavioral, morphological and biochemical features. In order to perform comparative studies we sequenced and assembled genomes of 4 chironomids from different habitats and also sequenced whole-genome RNA of their larvae in control and stressed conditions. It was shown that compact genome sizes (up to 200 Mb) are typical for Chironomidae, while changes in size of a genome are mediated by elongation and shortening of introns length, as well as by changes in quantity and content of dispersed repeats. For all extremophile species under consideration species-specific gene expansion accompanied by formation of compact clusters in a genome was detected. The most amplitudinous reaction towards abiotic stress (desiccation) was shown by anhydrobiotic species Polypedilum vanderplanki (Africa). As for HSP-coding genes, it was noticed that genes of HSP20 and HSP70 show the most dramatic and universal up-regulation of expression in response to abiotic stress, while genes of chaperonins (HSP60) tend to be up-regulated in response to desiccation, but not to heat shock. But the most surprising notion was linked to acid-tolerant species Polipedilum cf. tamanigrum (Japan), because none of HSP-coding genes in this species showed statistically significant up-regulation, what may be explained by absence of special regulatory sequence – heat shock element (HSE) in their promotor regions.