Functional chimeric genes in ciliates: An instructive case from Euplotes raikovi

Gene ◽  
2021 ◽  
Vol 767 ◽  
pp. 145186
Author(s):  
Francesca Ricci ◽  
Pierangelo Luporini ◽  
Claudio Alimenti ◽  
Adriana Vallesi
1999 ◽  
Vol 19 (11) ◽  
pp. 7751-7758 ◽  
Author(s):  
Wei Yan ◽  
Elizabeth A. Craig

ABSTRACT Hsp40s are ubiquitous, conserved proteins which function with molecular chaperones of the Hsp70 class. Sis1 is an essential Hsp40 of the cytosol of Saccharomyces cerevisiae, thought to be required for initiation of translation. We carried out a genetic analysis to determine the regions of Sis1 required to perform its key function(s). A C-terminal truncation of Sis1, removing 231 amino acids but retaining the N-terminal 121 amino acids encompassing the J domain and the glycine-phenylalanine-rich (G-F) region, was able to rescue the inviability of a Δsis1 strain. The yeast cytosol contains other Hsp40s, including Ydj1. To determine which regions carried the critical determinants of Sis1 function, we constructed chimeric genes containing portions of SIS1 and YDJ1. A chimera containing the J domain of Sis1 and the G-F region of Ydj1 could not rescue the lethality of the Δsis1 strain. However, a chimera with the J domain of Ydj1 and the G/F region of Sis1 could rescue the strain’s lethality, indicating that the G-F region is a unique region required for the essential function of Sis1. However, a J domain is also required, as mutants expected to cause a disruption of the interaction of the J domain with Hsp70 are inviable. We conclude that the G-F region, previously thought only to be a linker or spacer region between the J domain and C-terminal regions of Hsp40s, is a critical determinant of Sis1 function.


2021 ◽  
Author(s):  
Hui Zhao ◽  
Zhenlong Zhou ◽  
Guangmeng Li ◽  
Gang Liu ◽  
Shuyin Lin ◽  
...  

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Martijn van den Hurk ◽  
Peter Pelzer ◽  
Rianne Riemens

Abstract Background Merwede is an envisioned neighbourhood in Utrecht (the Netherlands) that provides an instructive case to learn about the governance challenges of digital mobility platforms. Unique about Merwede is how the development of a mobility platform is envisioned to be integrated into the development of a new neighbourhood. Methodology This article discusses the case of Merwede and provides insights into its proposed mobility platform and how it is made. It illuminates governance challenges relevant to the design and operation of an unconventional mobility concept by disentangling outstanding practical issues concerning three key governance dimensions—organizational structures, decision-making processes, and instruments. Results The research provides an empirical illustration of governance questions that come up when mobility becomes a service and is integrated into the urban fabric from the very beginning of a development process. Already in the plan development stage, Merwede illustrates that difficult decisions are to be made and competing interests come to the fore.


Genetics ◽  
2004 ◽  
Vol 166 (2) ◽  
pp. 947-957 ◽  
Author(s):  
John G Jelesko ◽  
Kristy Carter ◽  
Whitney Thompson ◽  
Yuki Kinoshita ◽  
Wilhelm Gruissem

Abstract Paralogous genes organized as a gene cluster can rapidly evolve by recombination between misaligned paralogs during meiosis, leading to duplications, deletions, and novel chimeric genes. To model unequal recombination within a specific gene cluster, we utilized a synthetic RBCSB gene cluster to isolate recombinant chimeric genes resulting from meiotic recombination between paralogous genes on sister chromatids. Several F1 populations hemizygous for the synthRBCSB1 gene cluster gave rise to Luc+ F2 plants at frequencies ranging from 1 to 3 × 10-6. A nonuniform distribution of recombination resolution sites resulted in the biased formation of recombinant RBCS3B/1B::LUC genes with nonchimeric exons. The positioning of approximately half of the mapped resolution sites was effectively modeled by the fractional length of identical DNA sequences. In contrast, the other mapped resolution sites fit an alternative model in which recombination resolution was stimulated by an abrupt transition from a region of relatively high sequence similarity to a region of low sequence similarity. Thus, unequal recombination between paralogous RBCSB genes on sister chromatids created an allelic series of novel chimeric genes that effectively resulted in the diversification rather than the homogenization of the synthRBCSB1 gene cluster.


Neuron ◽  
1991 ◽  
Vol 6 (2) ◽  
pp. 201-210 ◽  
Author(s):  
Janis Lem ◽  
Meredithe L. Applebury ◽  
Jeffrey D. Falk ◽  
John G. Flannery ◽  
Melvin I. Simon

1985 ◽  
Vol 5 (3) ◽  
pp. 518-528
Author(s):  
S Silver ◽  
B Roizman

True gamma or gamma 2 genes, unlike alpha, beta, and gamma 1 (beta gamma) genes of herpes simplex virus 1 (HSV-1), stringently require viral DNA synthesis for their expression. We report that gamma 2 genes resident in cells were induced in trans by infection with HSV-1 but that the induction did not require amplification of either the resident gene or the infecting viral genome. Specifically, to test the hypothesis that expression of these genes is amplification dependent, we constructed two sets of gamma 2-thymidine kinase (TK) chimeric genes. The first (pRB3038) consisted of the promoter-regulatory region and a portion of 5'-transcribed noncoding region of the domain of a gamma 2 gene identified by Hall et al. (J. Virol. 43:594-607) in the HSV-1(F) BamHI fragment D' to the 5'-transcribed noncoding and coding regions of the TK gene. The second (pRB3048) contained, in addition, an origin of HSV-1 DNA replication. Cells transfected with either the first or second construct and selected for the TK+ phenotype were then tested for TK induction after superinfection with HSV-1(F) delta 305, containing a deletion in the coding sequences of the TK gene, and viruses containing, in addition, a ts lesion in the alpha 4 regulatory protein (ts502 delta 305) or in the beta 8 major DNA-binding protein (tsHA1 delta 305). The results were as follows: induction by infection with TK- virus of chimeric TK genes with or without an origin of DNA replication was dependent on functional alpha 4 protein but not on viral DNA synthesis; the resident chimeric gene in cells selected for G418 (neomycin) resistance was regulated in the same fashion; the chimeric gene recombined into the viral DNA was regulated as a gamma 2 gene in that its expression in infected cells was dependent on viral DNA synthesis; the gamma 2-chimeric genes resident in the host and in viral genomes were transcribed from the donor BamHI fragment D' containing the promoter-regulatory domain of the gamma 2 gene. The significance of the differential regulation of gamma 2 genes in the environments of host and viral genomes by viral trans-acting factors is discussed.


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