Characterization of the shsp genes in Drosophila buzzatii and association between the frequency of Valine mutations in hsp23 and climatic variables along a longitudinal gradient in Australia

Abstract

The small heat shock gene (shsp) cluster of Drosophila buzzatii was sequenced and the gene order and DNA sequence were compared with those of the shsps in Drosophila melanogaster. The D. buzzatii shsp cluster contains an inversion and a duplication of hsp26. A phylogenetic tree was constructed based on hsp26 genes from several Drosophila species of the Sophophora and Drosophila subgenera. The tree shows first a separation of the Sophophora and the Drosophila subgenera and then the Drosophila subgenus is divided into the Hawaiian Drosophila and the repleta/virilis groups. Only the latter contain a duplicated hsp26. Comparing the gene organisation of the shsp cluster shows that all the Drosophila subgenus species contain the inversion. Putative heat shock elements (HSE) were found in the promoters of all the shsp and putative regulator elements for tissue specific expression were found in the promoter of hsp23, hsp27 and one of the hsp26 genes. hsp23 was found to be polymorphic for four non-synonymous changes that all lead to exchange of a Valine. The duplicated hsp26 gene in D. buzzatii (phsp26) was polymorphic for two non-synonymous changes. The allele frequencies of these variants were determined in nine D. buzzatii populations covering most of its distribution in Australia using high-resolution melting curves. The allele frequencies of one of the hsp23 variants showed a significant linear regression with longitude and the pooled frequency of the four Valine changes of hsp23 in the nine populations showed a significant linear regression with longitude and with a composite measure of climatic variables.

Maternal loading of a small heat shock protein increases embryo thermal tolerance inDrosophila melanogaster

“…Based on these studies, it is well established that HSP expression is an adaptive physiological mechanism for coping with acute thermal stress. Accordingly, population-level comparisons have discovered clinal variation in Hsp23 alleles across environmental thermal gradients in Drosophila buzzatii in Australia (Frydenberg et al, 2010), as well as clines in allele frequencies of Hsp23 and Hsp26 among D. melanogaster populations in Australia (Frydenberg et al, 2003). In addition, laboratory thermal selection studies have found evolved changes in HSP expression to accompany adaptive shifts in upper thermal limits (Rudolph et al, 2010;Kelly et al, 2017).…”

The Gln32Lys Polymorphism in HSP22 of Zhikong Scallop Chlamys farreri Is Associated with Heat Tolerance

“…Although the finding of association between HSP22 polymorphisms and some certain traits is of high interest, the detailed mechanisms under the phenomenon are still far from well understood. Inspiringly, accumulating evidences have suggested that genetic polymorphisms in the coding regions could affect proteins activity [42] , [43] , which could perhaps explain why they were associated with some certain traits. For example, the mutation of Valine to Leucine can change the biological activity of the antimicrobial peptide protegrin-1 [42] , the specific mutations in Cosmc from patients with Tn syndrome lead to the loss of its chaperone function [44] , and the nonsynonymous mutation in the coding region of human Hsp70 gene can affect the chaperone function [19] .…”

Identification and Allelic Variants Associated With Cold Tolerance of PmPIAS in Pinctada fucata martensii

“…In the present study, 11 SNP sites were found in the exon region of PmPIAS , and they demonstrated significant differences between the R and W in genotype and allele. Accumulating evidence suggested that genetic polymorphisms in the coding regions could affect protein activity or effect of translation ( Gottler et al, 2008 ; Frydenberg et al, 2010 ). The SNPs detected in the present study may provide a potential site for the cold tolerance selection in the future.…”