A comprehensive analysis of the importance of translation initiation factors for Haloferax volcanii applying deletion and conditional depletion mutants

Translation is an important step in gene expression. The initiation of translation is phylogenetically diverse, since currently five different initiation mechanisms are known. For bacteria the three initiation factors IF1 – IF3 are described in contrast to archaea and eukaryotes, which contain a considerably higher number of initiation factor genes. As eukaryotes and archaea use a non-overlapping set of initiation mechanisms, orthologous proteins of both domains do not necessarily fulfill the same function. The genome of Haloferax volcanii contains 14 annotated genes that encode (subunits of) initiation factors. To gain a comprehensive overview of the importance of these genes, it was attempted to construct single gene deletion mutants of all genes. In 9 cases single deletion mutants were successfully constructed, showing that the respective genes are not essential. In contrast, the genes encoding initiation factors aIF1, aIF2γ, aIF5A, aIF5B, and aIF6 were found to be essential. Factors aIF1A and aIF2β are encoded by two orthologous genes in H. volcanii. Attempts to generate double mutants failed in both cases, indicating that also these factors are essential. A translatome analysis of one of the single aIF2β deletion mutants revealed that the translational efficiency of the second ortholog was enhanced tenfold and thus the two proteins can replace one another. The phenotypes of the single deletion mutants also revealed that the two aIF1As and aIF2βs have redundant but not identical functions. Remarkably, the gene encoding aIF2α, a subunit of aIF2 involved in initiator tRNA binding, could be deleted. However, the mutant had a severe growth defect under all tested conditions. Conditional depletion mutants were generated for the five essential genes. The phenotypes of deletion mutants and conditional depletion mutants were compared to that of the wild-type under various conditions, and growth characteristics are discussed

Compounds, learning mechanisms, and the continuity hypothesis in language acquisition

Nobody denies that the input plays an important role in language acquisition, but the issue as to whether the input is sufficient to drive language learning is still a matter of debate. In this paper we examine children’s acquisition of synthetic compounds in English and Dutch. Despite having necessarily different input, Dutch- and English-speaking children produce the same set of non-adult forms when acquiring synthetic compounds: drive-truck and driver-truck, but not truck-drive. In this paper we review three proposals for the English-speaking children’s data and examine how they fair in light of the Dutch-speaking children’s data. The proposals fall into two types: (i) input-driven proposals that argue that frequent, but unrelated, aspects of the input are causing the non-adult forms we see and (ii) grammar-driven proposals that argue that the children’s non-adult forms are actually driven by the adult derivation. Given the inability for the two experience-driven accounts to explain why Dutch- and English-speaking children produce the same non-adult forms, we will ultimately claim that only a proposal that relies on the grammar explains the data at hand. More specifically we argue that children proceed from their earliest non-adult productions to the adult truck-driver form in a manner consistent with a strong version of the continuity hypothesis. Rather than being approximations of the adult forms that are affected by other constructions in the input, the forms that children produce are steps in the adult derivation of synthetic compounds. As children learn more about the structure and can confidently advance the structure without missing any of the adult features, the forms progress towards the adult truck-driver form

TRP Channel Regulation of Estrogen Signaling

Abstract Calcium regulates numerous cell functions including growth and development. Calcium can enter cells through transient receptor potential channels (TRPCs). Previous studies in MCF-7 cells have suggested that the expression of one particular TRPC, TRPC6, correlates with cell transformation and disease progression. Calcium has several cellular targets including the Calcium/Calmodulin-dependent protein kinases (CaM Ks) and ERK. Previous work has shown that estrogen (E2) may utilize CaM Ks and ERK to promote breast cancer cell proliferation, however the possible involvement of TRPCs in this pathway is currently unknown. Our objective was to understand which E2 receptor is used in our system and if TRPCs participate in the control of CaM Kinase activation of ERK in MCF-7 cells. Specifically, we wanted to explore if E2 may utilize TRPCs particularly, TRPC6, upstream of the ERK pathway in MCF-7 cells. E2 stimulation of MCF-7 cells and the estrogen receptor alpha (α) inhibitor, MPP, completely blocked ERK activity. In contrast, MPP did not block EGF stimulation of ERK. MCF-7 cells express endogenous TRPC6 protein and TRPC inhibitors, APB and SK&F, both blocked ERK activation downstream of E2. In addition, neither APB or SK&F inhibited EGF activation of ERK. Results from these studies suggest that E2 is capable of activating ERK through the specifically through the alpha form of the estrogen receptor and TRPCs

Transcription Factor Regulation of ERK and Estrogen in MCF-7 Cells

Abstract ERK is activated by increased intracellular calcium downstream of the hormone estrogen (E2). E2 activates ERK via the CaM Kinases, specifically CaM KK and CaM KI in MCF-7 cells. ERK may control cell growth and proliferation through Elk-1, Rsk, SRF, CREB, and numerous other molecules and nuclear targets. Vitamin D, a hormone, has proven to be an effective antagonist of ERK and MCF-7 breast cancer cell growth. Our goal was to evaluate if the E2 pathway working through CaM KK and ERK regulated the transcription factors Elk-1, CREB, and SRF. We also examined the ability of vitamin D to antagonize ERK activation of its downstream targets. Interestingly, E2 stimulation of MCF-7 cells activated both ERK and Elk-1 an effect that was blocked by inhibiting both CaM KK and ERK. E2 treatment of MCF-7 cells also triggered a significant increase in SRF and CREB phosphorlation in a CaM KK- and ERK-dependent manner. Dimerization of transcription factors may enhance DNA binding and gene expression. E2 stimulation of MCF-7 cells promoted the formation of a molecular complex between endogenous Elk-1 and SRF. Finally, E2 triggered a prolonged increased in ERK and Elk-1 phosphorylation, both of which were blocked by vitamin D treatment. Taken together our data demonstrates several transcriptional targets for E2 working through CaM KK and their inhibition by vitamin D signaling

01-37 Fifth Sunday After the Epiphany

Spark your thoughts for February 4, the 5th Sunday after the Epiphany. Jessica Bordeleau hosts professors of homiletics- Dr. Peter Nafzger and Dr. David Schmitt in a discussion of the lectionary texts from Isaiah 40:21–31, 1 Corinthians 9:16–27, Mark 1:29–39, Psalm 147:1–11. This podcast is also available at Concordia Theology-Podcast, and all major podcast platforms Lectionary Kick-start

01-23 Pentecost 21, 21th Sunday after Pentecost, October 22, 2023.

Spark your thoughts for October 22, the 21th Sunday after Pentecost. Jessica Bordeleau hosts professors of homiletics- Dr. Peter Nafzger and Dr. David Schmitt in a discussion of the lectionary texts from Isaiah 45:1–7, 1 Thessalonians 1:1–10 and Matthew 22:15–22 . This podcast is also available at Concordia Theology-Podcast, and all major podcast platforms Lectionary Kick-start

01-28 Last Sunday of the Church Year, November 26, 2023.

Spark your thoughts for November 26, the last Sunday after Pentecost. Jessica Bordeleau hosts professors of homiletics- Dr. Peter Nafzger and Dr. David Schmitt in a discussion of the lectionary texts from Ezekiel 34:11–16, 1 Corinthians 15:20–28, Matthew 25:31–46 and Psalm 95:1–6. This podcast is also available at Concordia Theology-Podcast, and all major podcast platforms Lectionary Kick-start

01-35 Third Sunday After the Epiphany

Spark your thoughts for January 21, the 3rd Sunday after the Epiphany. Jessica Bordeleau hosts professors of homiletics- Dr. Peter Nafzger and Dr. David Schmitt in a discussion of the lectionary texts from Jonah 3:1–5, 1 Corinthians 7:29–31, Mark 1:14–20, Psalm 62:1–12. This podcast is also available at Concordia Theology-Podcast, and all major podcast platforms Lectionary Kick-start

01-09 Pentecost 7, 7th Sunday after Pentecost, July 16, 2023.

Spark your thoughts for July 16, the 7th Sunday after Pentecost. Jessica Bordeleau hosts professors of homiletics- Dr. Peter Nafzger and Dr. David Schmitt in a discussion of the lectionary texts Isaiah 55, Romans 8, Matthew 13. This podcast is also available at Concordia Theology-Podcast, and all major podcast platforms Lectionary Kick-start

01-17 Pentecost 15, 15th Sunday after Pentecost, September 10, 2023.

Spark your thoughts for September 10, the 15th Sunday after Pentecost. Jessica Bordeleau hosts professors of homiletics- Dr. Peter Nafzger and Dr. David Schmitt in a discussion of the lectionary texts from Ezekiel 33:7–9, Romans 13:1–10, Matthew 18:1–20. This podcast is also available at Concordia Theology-Podcast, and all major podcast platforms Lectionary Kick-start