scholarly journals The dynamics of HD-ZIP III - ZPR protein interactions play essential roles in embryogenesis, meristem function and organ development

2021 ◽  
Author(s):  
Anna Vitlin Gruber ◽  
Melissa Kosty ◽  
Yasaman Jami-Alahmadi ◽  
James Wohlschlegel ◽  
Jeff A Long

Maintaining a stem cell population while developing lateral organs is a crucial aspect of plant development. Studies have shown that a family of micro proteins, the LITTLE ZIPPERS (ZPR), are involved in this process by repressing the activity of HD-ZIP III transcription factors. However, the unique role of each ZPR has not been thoroughly characterized. In this work, we use genetics, imaging, and biochemistry to create a detailed picture of ZPR family expression and their specific interactions with HD-ZIP IIIs. CRISPR/Cas9 was implemented to isolate single loss-of-function ZPR alleles as well as higher-order mutant combinations. A single mutation in ZPR1, ZPR3, and ZPR4 affects the development of the cotyledons during embryogenesis. Additionally, double mutant analyses indicates both unique roles for each ZPR protein as well as redundancy. Using ZPR tagged lines we show that while ZPR3 and ZPR4 have a similar pattern of accumulation as the HD-ZIP IIIs, ZPR1 and ZPR2 accumulation is more limited. Immuno-precipitations (IP) with tagged ZPR proteins are mainly enriched with the anticipated HD-ZIP III partners. Although ZPRs interact with all HD-ZIP IIIs, an apparent preference of heterodimer formation with REVOLUTA is observed. Our work highlights that the dynamics of ZPR protein accumulation together with the strength of ZPR-HD-ZIP III interactions provide an added layer of complexity to the regulation of HD-ZIP IIIs during plant development.

2017 ◽  
Vol 313 (5) ◽  
pp. F1106-F1115 ◽  
Author(s):  
Marie-Lyne Fillion ◽  
Jasmine El Andalousi ◽  
Fatima Tokhmafshan ◽  
Vasikar Murugapoopathy ◽  
Christine L. Watt ◽  
...  

Odd-skipped related 1 (Osr1) is a transcriptional repressor that plays critical roles in maintaining the mesenchymal stem cell population within the developing kidney. Here, we report that newborn pups with a heterozygous null mutation in Osr1 exhibit a 21% incidence of vesicoureteric reflux and have hydronephrosis and urinary tract duplications. Newborn pups have a short intravesical ureter, resulting in a less competent ureterovesical junction which arises from a delay in urinary tract development. We describe a new domain of Osr1 expression in the ureteral mesenchyme and within the developing bladder in the mouse. OSR1 was sequenced in 186 children with primary vesicoureteric reflux, and 17 have single nucleotide polymorphisms. Fifteen children have a common synonymous variant, rs12329305 , one child has a rare nonsynonymous variant, rs3440471 , and one child has a rare 5′-UTR variant, rs45535040 . The impact of these SNPs is not clear; therefore, the role of OSR1 in human disease remains to be elucidated. Osr1 is a candidate gene implicated in the pathogenesis of vesicoureteric reflux and congenital abnormalities of the kidney and urinary tract in mice.


2021 ◽  
Author(s):  
Jesus Preciado ◽  
Kevin Begcy ◽  
Tie Liu

Leaf laminar growth and adaxial-abaxial boundary formation are fundamental outcomes of plant development. Boundary and laminar growth coordinate the further patterning and growth of the leaf, directing the differentiation of cell types within the top and bottom domains and promoting initiation of lateral organs along their adaxial/abaxial axis. Leaf adaxial-abaxial polarity specification and laminar out-growth are regulated by two transcription factors, REVOLUTA (REV) and KANADI (KAN). ABA INSENSITIVE TO GROWTH 1 (ABIG1) is a HOMEODOMAIN-LEUCINE ZIPPER (HD-ZIP) Class II transcription factor and is a direct target of the adaxial-abaxial regulators REV and KAN. To investigate the role of ABIG1 in the leaf development and establishment of polarity, we examined the phenotypes of both gain-of-function and loss-of-function mutants. Through genetic interaction analysis with REV and KAN mutants, we have determined that ABIG1 plays a role in leaf laminar-growth as well as in adaxial-abaxial polarity establishment. Genetic and physical interaction assays showed that ABIG1 interacts with the transcriptional corepressor TOPLESS (TPL). This study provides new evidence that another HD-ZIP II gene, ABIG1, facilitates growth through the corepressor TPL.


2013 ◽  
Vol 54 ◽  
pp. 79-90 ◽  
Author(s):  
Saba Valadkhan ◽  
Lalith S. Gunawardane

Eukaryotic cells contain small, highly abundant, nuclear-localized non-coding RNAs [snRNAs (small nuclear RNAs)] which play important roles in splicing of introns from primary genomic transcripts. Through a combination of RNA–RNA and RNA–protein interactions, two of the snRNPs, U1 and U2, recognize the splice sites and the branch site of introns. A complex remodelling of RNA–RNA and protein-based interactions follows, resulting in the assembly of catalytically competent spliceosomes, in which the snRNAs and their bound proteins play central roles. This process involves formation of extensive base-pairing interactions between U2 and U6, U6 and the 5′ splice site, and U5 and the exonic sequences immediately adjacent to the 5′ and 3′ splice sites. Thus RNA–RNA interactions involving U2, U5 and U6 help position the reacting groups of the first and second steps of splicing. In addition, U6 is also thought to participate in formation of the spliceosomal active site. Furthermore, emerging evidence suggests additional roles for snRNAs in regulation of various aspects of RNA biogenesis, from transcription to polyadenylation and RNA stability. These snRNP-mediated regulatory roles probably serve to ensure the co-ordination of the different processes involved in biogenesis of RNAs and point to the central importance of snRNAs in eukaryotic gene expression.


2020 ◽  
Vol 64 (2) ◽  
pp. 251-261
Author(s):  
Jessica E. Fellmeth ◽  
Kim S. McKim

Abstract While many of the proteins involved in the mitotic centromere and kinetochore are conserved in meiosis, they often gain a novel function due to the unique needs of homolog segregation during meiosis I (MI). CENP-C is a critical component of the centromere for kinetochore assembly in mitosis. Recent work, however, has highlighted the unique features of meiotic CENP-C. Centromere establishment and stability require CENP-C loading at the centromere for CENP-A function. Pre-meiotic loading of proteins necessary for homolog recombination as well as cohesion also rely on CENP-C, as do the main scaffolding components of the kinetochore. Much of this work relies on new technologies that enable in vivo analysis of meiosis like never before. Here, we strive to highlight the unique role of this highly conserved centromere protein that loads on to centromeres prior to M-phase onset, but continues to perform critical functions through chromosome segregation. CENP-C is not merely a structural link between the centromere and the kinetochore, but also a functional one joining the processes of early prophase homolog synapsis to late metaphase kinetochore assembly and signaling.


Diabetes ◽  
2019 ◽  
Vol 68 (Supplement 1) ◽  
pp. 142-OR
Author(s):  
MASAJI SAKAGUCHI ◽  
SHOTA OKAGAWA ◽  
SAYAKA KITANO ◽  
TATSUYA KONDO ◽  
EIICHI ARAKI

2021 ◽  
Vol 12 (4) ◽  
Author(s):  
Joanne M. Hildebrand ◽  
Bernice Lo ◽  
Sara Tomei ◽  
Valentina Mattei ◽  
Samuel N. Young ◽  
...  

AbstractMaturity-onset diabetes of the young, MODY, is an autosomal dominant disease with incomplete penetrance. In a family with multiple generations of diabetes and several early onset diabetic siblings, we found the previously reported P33T PDX1 damaging mutation. Interestingly, this substitution was also present in a healthy sibling. In contrast, a second very rare heterozygous damaging mutation in the necroptosis terminal effector, MLKL, was found exclusively in the diabetic family members. Aberrant cell death by necroptosis is a cause of inflammatory diseases and has been widely implicated in human pathologies, but has not yet been attributed functions in diabetes. Here, we report that the MLKL substitution observed in diabetic patients, G316D, results in diminished phosphorylation by its upstream activator, the RIPK3 kinase, and no capacity to reconstitute necroptosis in two distinct MLKL−/− human cell lines. This MLKL mutation may act as a modifier to the P33T PDX1 mutation, and points to a potential role of impairment of necroptosis in diabetes. Our findings highlight the importance of family studies in unraveling MODY’s incomplete penetrance, and provide further support for the involvement of dysregulated necroptosis in human disease.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Maria I. Alvarez-Vergara ◽  
Alicia E. Rosales-Nieves ◽  
Rosana March-Diaz ◽  
Guiomar Rodriguez-Perinan ◽  
Nieves Lara-Ureña ◽  
...  

AbstractThe human Alzheimer’s disease (AD) brain accumulates angiogenic markers but paradoxically, the cerebral microvasculature is reduced around Aß plaques. Here we demonstrate that angiogenesis is started near Aß plaques in both AD mouse models and human AD samples. However, endothelial cells express the molecular signature of non-productive angiogenesis (NPA) and accumulate, around Aß plaques, a tip cell marker and IB4 reactive vascular anomalies with reduced NOTCH activity. Notably, NPA induction by endothelial loss of presenilin, whose mutations cause familial AD and which activity has been shown to decrease with age, produced a similar vascular phenotype in the absence of Aß pathology. We also show that Aß plaque-associated NPA locally disassembles blood vessels, leaving behind vascular scars, and that microglial phagocytosis contributes to the local loss of endothelial cells. These results define the role of NPA and microglia in local blood vessel disassembly and highlight the vascular component of presenilin loss of function in AD.


2021 ◽  
Vol 43 (2) ◽  
pp. 767-781
Author(s):  
Vanessa Pinatto Gaspar ◽  
Anelise Cardoso Ramos ◽  
Philippe Cloutier ◽  
José Renato Pattaro Junior ◽  
Francisco Ferreira Duarte Junior ◽  
...  

KIN (Kin17) protein is overexpressed in a number of cancerous cell lines, and is therefore considered a possible cancer biomarker. It is a well-conserved protein across eukaryotes and is ubiquitously expressed in all cell types studied, suggesting an important role in the maintenance of basic cellular function which is yet to be well determined. Early studies on KIN suggested that this nuclear protein plays a role in cellular mechanisms such as DNA replication and/or repair; however, its association with chromatin depends on its methylation state. In order to provide a better understanding of the cellular role of this protein, we investigated its interactome by proximity-dependent biotin identification coupled to mass spectrometry (BioID-MS), used for identification of protein–protein interactions. Our analyses detected interaction with a novel set of proteins and reinforced previous observations linking KIN to factors involved in RNA processing, notably pre-mRNA splicing and ribosome biogenesis. However, little evidence supports that this protein is directly coupled to DNA replication and/or repair processes, as previously suggested. Furthermore, a novel interaction was observed with PRMT7 (protein arginine methyltransferase 7) and we demonstrated that KIN is modified by this enzyme. This interactome analysis indicates that KIN is associated with several cell metabolism functions, and shows for the first time an association with ribosome biogenesis, suggesting that KIN is likely a moonlight protein.


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