scholarly journals Evolution of carnivorous traps from planar leaves through simple shifts in gene expression

Science ◽  
2019 ◽  
Vol 367 (6473) ◽  
pp. 91-96 ◽  
Author(s):  
Christopher D. Whitewoods ◽  
Beatriz Gonçalves ◽  
Jie Cheng ◽  
Minlong Cui ◽  
Richard Kennaway ◽  
...  

Leaves vary from planar sheets and needle-like structures to elaborate cup-shaped traps. Here, we show that in the carnivorous plant Utricularia gibba, the upper leaf (adaxial) domain is restricted to a small region of the primordium that gives rise to the trap’s inner layer. This restriction is necessary for trap formation, because ectopic adaxial activity at early stages gives radialized leaves and no traps. We present a model that accounts for the formation of both planar and nonplanar leaves through adaxial-abaxial domains of gene activity establishing a polarity field that orients growth. In combination with an orthogonal proximodistal polarity field, this system can generate diverse leaf forms and account for the multiple evolutionary origins of cup-shaped leaves through simple shifts in gene expression.

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Mohammad M. Karimi ◽  
Ya Guo ◽  
Xiaokai Cui ◽  
Husayn A. Pallikonda ◽  
Veronika Horková ◽  
...  

AbstractCD4 and CD8 mark helper and cytotoxic T cell lineages, respectively, and serve as coreceptors for MHC-restricted TCR recognition. How coreceptor expression is matched with TCR specificity is central to understanding CD4/CD8 lineage choice, but visualising coreceptor gene activity in individual selection intermediates has been technically challenging. It therefore remains unclear whether the sequence of coreceptor gene expression in selection intermediates follows a stereotypic pattern, or is responsive to signaling. Here we use single cell RNA sequencing (scRNA-seq) to classify mouse thymocyte selection intermediates by coreceptor gene expression. In the unperturbed thymus, Cd4+Cd8a- selection intermediates appear before Cd4-Cd8a+ selection intermediates, but the timing of these subsets is flexible according to the strength of TCR signals. Our data show that selection intermediates discriminate MHC class prior to the loss of coreceptor expression and suggest a model where signal strength informs the timing of coreceptor gene activity and ultimately CD4/CD8 lineage choice.


1991 ◽  
Vol 99 (2) ◽  
pp. 201-206 ◽  
Author(s):  
A.P. Wolffe

DNA replication has a key role in many developmental processes. Recent progress in understanding events at the replication fork suggests mechanisms for both establishing and maintaining programs of eukaryotic gene activity. In this review, I discuss the consequences of replication fork passage for preexisting chromatin structures and describe how the mechanism of nucleosome assembly at the replication fork may facilitate the formation of either transcriptionally active or repressed chromatin.


2018 ◽  
Vol 21 (1) ◽  
pp. 16-30 ◽  
Author(s):  
Samantha V. Beck ◽  
Katja Räsänen ◽  
Ehsan P. Ahi ◽  
Bjarni K. Kristjánsson ◽  
Skúli Skúlason ◽  
...  

2019 ◽  
Vol 105 (3) ◽  
pp. e390-e400 ◽  
Author(s):  
Stergios A Polyzos ◽  
Nikolaos Perakakis ◽  
Chrysoula Boutari ◽  
Jannis Kountouras ◽  
Wael Ghaly ◽  
...  

Abstract Aims To investigate circulating levels and liver gene expression of 3 hormonal pathways associated with obesity, insulin resistance, and inflammation to identify leads towards potential diagnostic markers and therapeutic targets in patients with nonalcoholic fatty liver disease (NAFLD). Methods We compared circulating levels of (1) proglucagon-derived hormones (glucagon-like peptide [GLP]-1, GLP-2, glicentin, oxyntomodulin, glucagon, major proglucagon fragment [MPGF]), (2) follistatins-activins (follistatin-like [FSTL]3, activin B), (3) IGF axis (insulin-like growth factor [IGF]-1, total and intact IGF binding protein [IGFBP]-3 and IGFBP-4, and pregnancy-associated plasma protein [PAPP]-A) in 2 studies: (1) 18 individuals with early stage NAFLD versus 14 controls (study 1; early NAFLD study) and in (2) 31 individuals with biopsy proven NAFLD (15 with simple steatosis [SS] and 16 with nonalcoholic steatohepatitis [NASH]), vs 50 controls (24 lean and 26 obese) (study 2). Liver gene expression was assessed in 22 subjects (12 controls, 5 NASH, 5 NASH-related cirrhosis). Results Patients in early stages of NAFLD demonstrate higher fasting MPGF and lower incremental increase of glicentin during oral glucose tolerance test than controls. In more advanced stages, FSTL3 levels are higher in NASH than simple steatosis and, within NAFLD patients, in those with more severe lobular and portal inflammation. The IGF-1/intact IGFBP-3 ratio is lower in patients with liver fibrosis. Genes encoding follistatin, activin A, activin B, and the IGF-1 receptor are higher in NASH. Conclusion MPGF and glicentin may be involved in early stages of NAFLD, whereas FSTL3 and IGF-1/intact IGFBP3 in the progression to NASH and liver fibrosis respectively, suggesting potential as diagnostic markers or therapeutic targets.


Plants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2226
Author(s):  
Jorge Xool-Tamayo ◽  
Yahaira Tamayo-Ordoñez ◽  
Miriam Monforte-González ◽  
José Armando Muñoz-Sánchez ◽  
Felipe Vázquez-Flota

The synthesis of the benzylisoquinoline alkaloids, sanguinarine and berberine, was monitored in Argemone mexicana L. (Papaveracea) throughout the early stages of its hypocotyl and seedling development. Sanguinarine was detected in the cotyledons right after hypocotyl emergence, and it increased continuously until the apical hook unbent, prior to the cotyledonary leaves unfolding, when it abruptly fell. In the cotyledonary leaves, it also remained at low levels. Throughout development, berberine accumulation required the formation of cotyledonary leaves, whereas it was quickly detected in the hypocotyl from the time it emerged. Interestingly, the alkaloids detected in the cotyledons could have been imported from hypocotyls, because no transcriptional activity was detected in there. However, after turning into cotyledonary leaves, important levels of gene expression were noted. Taken together, these results suggest that the patterns of alkaloid tissue distribution are established from very early development, and might require transport systems.


Development ◽  
1985 ◽  
Vol 89 (Supplement) ◽  
pp. 113-124
Author(s):  
Igor B. Dawid ◽  
Susan R. Haynes ◽  
Milan Jamrich ◽  
Erzsebet Jonas ◽  
Seiji Miyatani ◽  
...  

This article considers some aspects of the storage of macromolecules in the oocyte of Xenopus laevis and the activation of previously unexpressed genes during early embryogenesis. The large quantity and complex nature of poly(A)+ RNA accumulated in the egg provides the cleavage embryo with a supply of mRNA sufficient to sustain protein synthesis for several hours of development. Onset of gene activity at the midblastula transition (MBT) leads to the synthesis and accumulation of molecules of various RNA classes, including tRNAs, rRNAs, mRNAs and mitochondrial RNAs. At gastrulation the poly(A)+ RNA population is still qualitatively similar to that of the egg but some sequences not present in egg RNA have accumulated by this time. Through the use of a subtractive cDNA cloning procedure we have prepared a library of sequences that represent genes activated for the first time between MBT and gastrula. A study of several of these cDNA clones suggests that genes in this class are restricted in their activity to embryonic and tadpole stages.


Planta ◽  
1968 ◽  
Vol 83 (2) ◽  
pp. 166-170 ◽  
Author(s):  
Daniel R. Sorenson ◽  
William T. Jackson

2019 ◽  
Vol 116 (4) ◽  
pp. 1331-1336 ◽  
Author(s):  
Rebecca L. Young ◽  
Michael H. Ferkin ◽  
Nina F. Ockendon-Powell ◽  
Veronica N. Orr ◽  
Steven M. Phelps ◽  
...  

Social monogamy, typically characterized by the formation of a pair bond, increased territorial defense, and often biparental care, has independently evolved multiple times in animals. Despite the independent evolutionary origins of monogamous mating systems, several homologous brain regions and neuropeptides and their receptors have been shown to play a conserved role in regulating social affiliation and parental care, but little is known about the neuromolecular mechanisms underlying monogamy on a genomic scale. Here, we compare neural transcriptomes of reproductive males in monogamous and nonmonogamous species pairs ofPeromyscusmice,Microtusvoles, parid songbirds, dendrobatid frogs, andXenotilapiaspecies of cichlid fishes. We find that, while evolutionary divergence time between species or clades did not explain gene expression similarity, characteristics of the mating system correlated with neural gene expression patterns, and neural gene expression varied concordantly across vertebrates when species transition to monogamy. Our study provides evidence of a universal transcriptomic mechanism underlying the evolution of monogamy in vertebrates.


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