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

Evolution and genomic organization of the insect sHSP gene cluster and coordinate regulation in phenotypic plasticity

Background

Conserved syntenic gene complexes are rare in Arthropods and likely only retained due to functional constraint. Numerous sHSPs have been identified in the genomes of insects, some of which are located clustered in close proximity. Previous phylogenetic analyses of these clustered sHSP have been limited to a small number of holometabolous insect species and have not determined the pattern of evolution of the clustered sHSP genes (sHSP-C) in insect or Arthropod lineages.

Results

Using eight genomes from representative insect orders and three non-insect arthropod genomes we have identified that a syntenic cluster of sHSPs (sHSP-C) is a hallmark of most Arthropod genomes. Using 11 genomes from Hymenopteran species our phylogenetic analyses have refined the evolution of the sHSP-C in Hymenoptera and found that the sHSP-C is order-specific with evidence of birth-and-death evolution in the hymenopteran lineage. Finally we have shown that the honeybee sHSP-C is co-ordinately expressed and is marked by genomic features, including H3K27me3 histone marks consistent with coordinate regulation, during honeybee ovary activation.

Conclusions

The syntenic sHSP-C is present in most insect genomes, and its conserved coordinate expression and regulation implies that it is an integral genomic component of environmental response in arthropods.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12862-021-01885-8.

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

The protein inhibitor of activated STAT (PIAS) functions in diverse aspects, including immune response, cell apoptosis, cell differentiation, and proliferation. In the present study, the PIAS in the pearl oyster Pinctada fucata martensii was characterized. The sequence features of PmPIAS were similar to that of other PIAS sequences with PIAS typical domains, including SAP, Pro-Ile-Asn-Ile-Thr (PINIT), RLD domain, AD, and S/T-rich region. Homologous analysis showed that PmPIAS protein sequence showed the conserved primary structure compared with other species. Ribbon representation of PIAS protein sequences also showed a conserved structure among species, and the PINIT domain and RLD domain showed the conserved structure compared with the sequence of Homo sapiens. The expression pattern of PmPIAS in different tissues showed significant high expression in the gonad. PmPIAS also exhibited a significantly higher expression in the 1 and 2 days after cold tolerance stress (17°C) and showed its potential in the cold tolerance. The SNP analysis of the exon region of PmPIAS obtained 18 SNPs, and among them, 11 SNPs showed significance among different genotypes and alleles between cold tolerance selection line and base stock, which showed their potential in the breeding for cold tolerance traits.

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

Maternal investment is likely to have direct effects on offspring survival. In oviparous animals whose embryos are exposed to the external environment, maternal provisioning of molecular factors like mRNAs and proteins may help embryos cope with sudden changes in the environment. Here, we sought to modify the maternal mRNA contribution to offspring embryos and test for maternal effects on acute thermal tolerance in early embryos of Drosophila melanogaster We drove in vivo overexpression of a small heat shock protein gene (Hsp23) in female ovaries and measured the effects of acute thermal stress on offspring embryonic survival and larval development. We report that overexpression of the Hsp23 gene in female ovaries produced offspring embryos with increased thermal tolerance. We also found that brief heat stress in the early embryonic stage (0-1 h old) caused decreased larval performance later in life (5-10 days old), as indexed by pupation height. Maternal overexpression of Hsp23 protected embryos against this heat-induced defect in larval performance. Our data demonstrate that transient products of single genes have large and lasting effects on whole-organism environmental tolerance. Further, our results suggest that maternal effects have a profound impact on offspring survival in the context of thermal variability.

Geographic selection in the small heat shock gene complex differentiating populations of Drosophila pseudoobscura

Environmental temperature plays a crucial role in determining a species distribution and abundance by affecting individual physiological processes, metabolic activities, and developmental rates. Many studies have identified clinal variation in phenotypes associated with response to environmental stresses, but variation in traits associated with climatic adaptation directly attributed to sequence variation within candidate gene regions has been difficult to identify. Insect heat shock genes are possible agents of thermal tolerance because of their involvement in protein folding, traffic, protection, and renaturation at the cellular level in response to temperature stress. Previously, members of the Drosophila small heat shock protein (sHSP) complex (Hsp23, Hsp26, Hsp27, Hsp67Ba) have been implicated as candidate climatic adaptation genes; therefore, this research examines sequence variation at these genes in 2 distant populations of Drosophila pseudoobscura. Flies from Tempe, AZ (n = 30) and Cheney, WA (n = 17) were used in the study. We identify high differentiation in the heat-shock complex (F(ST) : 0.219**, 0.262*, 0.279***, 0.166 not significant) as compared with neighboring genes and Tajima's D values indicative of balancing selection (Mann-Whitney U = 38, n(1) = 10 n(2) = 4, P < 0.05 two-tailed), both of which are suggestive of such climatic adaptation.

The Gln32Lys polymorphism in HSP22 of Zhikong scallop Chlamys farreri is associated with heat tolerance

Background

Heat shock protein 22 is a member of small heat shock proteins with molecular chaperone activity. Though their multiple functions have been well characterized, there is no report about the association between the polymorphisms of HSP22 and heat tolerance.

Methodology

Three single nucleotide polymorphisms were identified in HSP22 from scallop Chlamys farreri (CfHSP22), and the +94 C-A locus was found to be nonsynonymous. Three genotypes at locus +94, A/A, A/C and C/C, were revealed by using Bi-PASA PCR analysis, and their frequencies were 19.5%, 27.6% and 52.9% in the heat resistant stock, while 9.3%, 17.4% and 73.3% in the heat susceptible stock, respectively. The frequency differences of the three genotypes were significant (P<0.05) between the two stocks. After incubating at 30°C for 84 h, the cumulative mortality of scallops with +94 C/C genotype and +94 A/C genotypes was 95% and 90%, respectively, which was significantly higher (P<0.01) than that of scallops with +94 A/A genotype (70%). The molecular chaperone activity of two His-tagged fusion proteins, rCfHSP22Q with +94 C/C genotype and rCfHSP22K with +94 A/A genotype were analyzed by testing the ability of protecting citrate synthase (CS) against thermal inactivation in vitro. After incubated with rCfHSP22Q or rCfHSP22K at 38°C for 1 h, the activity of CS lost 50% and 45%, and then recovered to 89% and 95% of the original activity following 1 h restoration at 22°C, respectively, indicating that the mutation from Gln to Lys at this site might have an impact on molecular chaperone activities of CfHSP22.

Conclusions

These results implied that the polymorphism at locus +94 of CfHSP22 was associated with heat tolerance of scallop, and the +94 A/A genotype could be a potential marker available in future selection of Zhikong scallop with heat tolerance.