Friday, October 12, 2012: 8:00 PM
Hall 4E/F (WSCC)
The Krüppel-like factors (Klf) are an ancient family of transcription factors that have been extensively studied for their roles in cell proliferation and differentiation. While their role in stem cell development is still being determined, there is evidence that without the transcription of some members of the Klf gene family, normal maintenance of pluripotency may not occur. Research with vertebrate model systems has shown that Klf-2, Klf-4 and Klf-5 coordinate the expression of other genes known to regulate pluripotency such as Oct4, Sox2 and Nanog. The role of Klf genes in the emerging model system, the ctenophore Mnemiopsis leidyi, is unknown. Our preliminary data suggests that Mnemiopsis leidyi has two Klf genes, Klf-a and Klf-b, and both genes are maternally provided. RNAseq data for Klf-a shows a high level of transcripts in the fertilized zygote relative to late stages of embryonic development. We hypothesize that Mnemiopsis Klf genes may be playing a role in the maintenance of stem cell pluripotency. I have cloned Klf-a and Klf-b from Mnemiopsis leidyi. Alignments to other distantly related metazoan Klf genes highlight the three zinc finger domains that are characteristic of all Krüppel-like factors. Molecular phylogenetic inference also supports the assignment to the Klf C2H2 zinc finger transcription factor gene family. As the phylum Ctenophora diverged very early in metazoan evolution, insight into the molecular genetics and expression dynamics of genes such as MlKlf-a and MlKlf-bimplicated in the maintenance of pluripotency will provide an enhanced understanding of the evolution of stem cell pathways.