Luna, a Drosophila KLF6/KLF7, is maternally required for synchronized nuclear and centrosome cycles in the preblastoderm embryo

Identification and Validation of Reference Genes for Gene Expression Analysis in Monochamus saltuarius Under Bursaphelenchus xylophilus Treatment

A special mutual relationship exists between the pine wood nematode (PWN) Bursaphelenchus xylophilus and its vector beetles of genus Monochamus, which enables PWN to spread, at the same time provides longhorned beetles with more weak hosts. PWN are attracted to the pupal chambers and then carried inside the trachea of beetle adults, which is a necessary part to complete the B. xylophilus infection cycle. The growth and immune responses of the vector beetle will affect this carrying process, however, they were rarely studied in Monochamus saltuarius. Real-time quantitative polymerase chain reaction (RT-qPCR), one of the most common methods for quantitative gene expression analysis, was performed to explore the key genes and pathways involved in the growth, development and immune responses of M. saltuarius at different developmental stages associated with infection of PWN and PWN treatment conditions. To enhance the accuracy of RT-qPCR data, the expression of target genes needs to be normalized with reference genes, which are stably expressed under varied experimental conditions. In our study, the stability of 14 candidate reference genes in M. saltuarius samples at different developmental stages associated with infection of PWN or PWN treatment conditions was evaluated using delta Ct, geNorm, NormFinder, BestKeeper and RefFinder algorithms. Moreover, KLF gene was used to validate the stability of the selected reference genes. Under experimental conditions of this study, RPL7 and TER were suitable reference genes at different developmental stages associated with infection of PWN. RPL7 and RPS5 were considered the most stable reference genes in the pupae treated with PWN. RPS5 and SNX6 could be used as reference genes in the adults treated with PWN. RPL7, EF1-γ, and RPS5 could be used as stable reference genes in all the samples. This work is the first to evaluate reference genes in M. saltuarius, laying a foundation for further gene expression experimental procedures and understanding the phoretic relationship between M. saltuarius and B. xylophilus.

Krüppel-like factor gene function in the ctenophore Mnemiopsis leidyi assessed by CRISPR/Cas9-mediated genome editing

The Krüppel-like factor (Klf) gene family encodes transcription factors that play an important role in the regulation of stem cell proliferation, cell differentiation and development in bilaterians. Although Klf genes have been shown to specify functionally various cell types in non-bilaterian animals, their role in early-diverging animal lineages has not been assessed. Thus, the ancestral activity of these transcription factors in animal development is not well understood. The ctenophore Mnemiopsis leidyi has emerged as an important non-bilaterian model system for understanding early animal evolution. Here, we characterize the expression and functional role of Klf genes during M. leidyi embryogenesis. Zygotic Klf gene function was assessed with both CRISPR/Cas9-mediated genome editing and splice-blocking morpholino oligonucleotide knockdown approaches. Abrogation of zygotic Klf expression during M. leidyi embryogenesis resulted in abnormal development of several organs, including the pharynx, tentacle bulbs and apical organ. Our data suggest an ancient role for Klf genes in regulating endodermal patterning, possibly through regulation of cell proliferation.

Kruppel-like factor 6 promotes macrophage inflammatory and hypoxia response

Macrophages are the professional phagocytes that protect the host from infection or injury. Tissue microenvironment at the site of injury and inflammation is characterized by low oxygen concentration and poor supply of nutrients. The responding macrophages have to advance against oxygen and nutrient gradients to reach the site of inflammation to perform host protection, and tissue repair functions. Thus, evolution has fashioned macrophages to orchestrate a coordinated inflammatory and hypoxic gene program to mount an effective immune response. Here, we discovered that Kruppel‐like factor 6 (KLF6) governs macrophage functions by promoting inflammatory and hypoxic response gene programming. Our in vivo studies revealed that myeloid‐KLF6‐deficient mice were highly resistant to endotoxin‐induced systemic inflammatory response syndrome symptomatology and mortality. Using complementary gain‐ and loss‐of‐function studies, we observed that KLF6 overexpression elevate and KLF6 deficiency attenuate inducible HIF1α expression in macrophages. Our integrated transcriptomics and gene set enrichment analysis studies uncovered that KLF6 deficiency attenuates broad inflammatory and glycolytic gene expression in macrophages. More importantly, overexpression of oxygen stable HIF1α reversed attenuated proinflammatory and glycolytic gene expression in KLF6‐deficient macrophages. Collectively, our studies uncovered that KLF6 govern inflammatory and hypoxic response by regulating HIF1α expression in macrophage.

KLF/SP Transcription Factor Family Evolution: Expansion, Diversification, and Innovation in Eukaryotes

The Krüppel-like factor and specificity protein (KLF/SP) genes play key roles in critical biological processes including stem cell maintenance, cell proliferation, embryonic development, tissue differentiation, and metabolism and their dysregulation has been implicated in a number of human diseases and cancers. Although many KLF/SP genes have been characterized in a handful of bilaterian lineages, little is known about the KLF/SP gene family in nonbilaterians and virtually nothing is known outside the metazoans. Here, we analyze and discuss the origins and evolutionary history of the KLF/SP transcription factor family and associated transactivation/repression domains. We have identified and characterized the complete KLF/SP gene complement from the genomes of 48 species spanning the Eukarya. We have also examined the phylogenetic distribution of transactivation/repression domains associated with this gene family. We report that the origin of the KLF/SP gene family predates the divergence of the Metazoa. Furthermore, the expansion of the KLF/SP gene family is paralleled by diversification of transactivation domains via both acquisitions of pre-existing ancient domains as well as by the appearance of novel domains exclusive to this gene family and is strongly associated with the expansion of cell type complexity.