scholarly journals Lineage-level divergence of copepod glycerol transporters and the emergence of isoform-specific trafficking regulation

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Marc Catalán-García ◽  
François Chauvigné ◽  
Jon Anders Stavang ◽  
Frank Nilsen ◽  
Joan Cerdà ◽  
...  

AbstractTransmembrane conductance of small uncharged solutes such as glycerol typically occurs through aquaglyceroporins (Glps), which are commonly encoded by multiple genes in metazoan organisms. To date, however, little is known concerning the evolution of Glps in Crustacea or what forces might underly such apparent gene redundancy. Here, we show that Glp evolution in Crustacea is highly divergent, ranging from single copy genes in species of pedunculate barnacles, tadpole shrimps, isopods, amphipods and decapods to up to 10 copies in diplostracan water fleas although with monophyletic origins in each lineage. By contrast the evolution of Glps in Copepoda appears to be polyphyletic, with surprisingly high rates of gene duplication occurring in a genera- and species-specific manner. Based upon functional experiments on the Glps from a parasitic copepod (Lepeophtheirus salmonis), we show that such lineage-level gene duplication and splice variation is coupled with a high rate of neofunctionalization. In the case of L. salmonis, splice variation of a given gene resulted in tissue- or sex-specific expression of the channels, with each variant evolving unique sites for protein kinase C (PKC)- or protein kinase A (PKA)-regulation of intracellular membrane trafficking. The combined data sets thus reveal that mutations favouring a high fidelity control of intracellular trafficking regulation can be a selection force for the evolution and retention of multiple Glps in copepods.

2020 ◽  
Author(s):  
Marc Catalán-García ◽  
Francois Chauvigne ◽  
Jon Anders Stavang ◽  
Frank Nilsen ◽  
Joan Cerda ◽  
...  

Abstract Transmembrane conductance of glycerol is typically facilitated by aquaglyceroporins (Glps), which are commonly encoded by multiple genes in metazoan organisms. To date, however, little is known concerning the evolution of Glps in Crustacea or what forces might underly such gene redundancy. Here we show that Glp evolution in Crustacea is highly divergent, ranging from single copy genes in species of tadpole shrimps, isopods, amphipods and decapods to up to 10 copies in diplostracan water fleas although with monophyletic origins in each lineage. By contrast Glp evolution in Copepoda appears to be polyphyletic, with high rates of gene duplication occurring in a genera- and species-specifc manner. Based upon functional experiments on the Glps from a parasitic copepod (Lepeophtheirus salmonis), we show that such lineage-level gene duplication and splice variation is coupled with a high rate of neofunctionalization. For L. salmonis, splice variation of a given gene resulted in tissue- or sex-specific expression of the channels, with each variant evolving unique sites for PKC or PKA regulation of intracellular membrane trafficking. The data thus reveal that mutations favouring a high fidelity control of intracellular trafficking regulation can be a selection force for the evolution and retention of multiple Glps in copepods.


Genetics ◽  
1993 ◽  
Vol 134 (4) ◽  
pp. 1271-1276
Author(s):  
T Ohta

Abstract The growth hormone-prolactin gene family in mammals is an interesting example of evolution by gene duplication. Divergence among members of duplicated gene families and among species was examined by using reported gene sequences of growth hormone, prolactin and their receptors. Sequence divergence among species was found to show a general tendency in which a generation-time effect is pronounced for synonymous substitutions but not so for nonsynonymous substitutions. Divergence among duplicated genes is characterized by the relatively high rate of nonsynonymous substitutions, i.e., the rate is close to that of synonymous ones. In view of the stage- and tissue-specific expression of duplicated genes, some of the amino acid substitutions among duplicated genes is likely to be caused by positive Darwinian selection.


2003 ◽  
Vol 10 (4) ◽  
pp. 520-524 ◽  
Author(s):  
Tamece T. Knowles ◽  
A. Rick Alleman ◽  
Heather L. Sorenson ◽  
David C. Marciano ◽  
Edward B. Breitschwerdt ◽  
...  

ABSTRACT Canine monocytic ehrlichiosis, caused by Ehrlichia canis or Ehrlichia chaffeensis, can result in clinical disease in naturally infected animals. Coinfections with these agents may be common in certain areas of endemicity. Currently, a species-specific method for serological diagnosis of monocytic ehrlichiosis is not available. Previously, we developed two indirect enzyme-linked immunosorbent assays (ELISAs) using the major antigenic protein 2 (MAP2) of E. chaffeensis and E. canis. In this study, we further characterized the conservation of MAP2 among various geographic isolates of each organism and determined if the recombinant MAP2 (rMAP2) of E. chaffeensis would cross-react with E. canis-infected dog sera. Genomic Southern blot analysis using digoxigenin-labeled species-specific probes suggested that map2 is a single-copy gene in both Ehrlichia species. Sequences of the single map2 genes of seven geographically different isolates of E. chaffeensis and five isolates of E. canis are highly conserved among the various isolates of each respective ehrlichial species. ELISA and Western blot analysis confirmed that the E. chaffeensis rMAP2 failed to serologically differentiate between E. canis and E. chaffeensis infections.


2005 ◽  
Vol 79 (1) ◽  
pp. 39-46 ◽  
Author(s):  
Toshihiro Nagamine ◽  
Yu Kawasaki ◽  
Tetsutaro Iizuka ◽  
Shogo Matsumoto

ABSTRACT In BmN cells infected with the baculovirus Bombyx mori nucleopolyhedrovirus (BmNPV), IE1, a principal transcriptional activator, localizes to sites of viral DNA replication. IE1 initially displays focal distribution in BmNPV-infected cells prior to DNA synthesis, whereas the protein expressed by transfection with the ie1 gene is distributed throughout the nucleoplasm instead of localized to discrete subnuclear structures. To identify the inducer of focus formation for IE1, we conducted transfection experiments with an IE1-GFP construct and found that cotransfection with genomic DNA fragments bearing the homologous region (hr) sequences caused the formation of IE1-green fluorescent protein (GFP) foci. The transfection of insect cells with a single plasmid containing exclusively the hr3 sequence and the IE1-GFP gene was sufficient to form IE1-GFP foci. These results suggest that hr elements are a primary determinant of the focal distribution of IE1. An analysis of a series of hr3 deletion mutants showed that a single copy of the direct repeat could induce the formation of IE1 foci. Targeted mutagenesis within the hr-binding domain of IE1-GFP caused impairment of the hr-dependent IE1 localization, suggesting that binding of IE1 to the hr elements is essential for the onset of IE1 focus formation. The observation of BmNPV IE1 foci in non-BmNPV-susceptible cells suggests that no species-specific factors are required for hr-dependent IE1 focus formation.


1989 ◽  
Vol 9 (12) ◽  
pp. 5537-5547 ◽  
Author(s):  
A Ray ◽  
P Sassone-Corsi ◽  
P B Sehgal

Interleukin-6 (IL-6) is a major systemic alarm signal that indicates the occurrence of tissue damage. The IL-6 gene is induced in various cell types by serum, inflammation-associated cytokines, viruses, and second-messenger agonists. There is an overall functional similarity between IL-6 and c-fos promoters, since transfection of excess amounts of either promoter DNA into intact HeLa cells modulates the function of the heterologous promoter construct. Furthermore, the transcription regulatory factor Fos transrepresses both the IL-6 and c-fos promoters. The 115-base pair (bp) region from -225 to -111 in the IL-6 5'-flanking region, which shares nucleotide sequence similarity with the c-fos serum response (SRE) and adjacent AP-1-like (the CGTCA motif) elements, confers responsiveness to several reagents, including serum, forskolin, and phorbol ester, upon the heterologous herpesvirus thymidine kinase (TK) promoter. In gel shift assays using nuclear extracts from HeLa cells, the 115-bp IL-6 enhancer formed several complexes that (i) were increased when extracts from induced HeLa cells were used and (ii) were inhibited most efficiently by the fos E DNA fragment (-700 to -100) and by c-fos oligonucleotides containing an intact AP-1-like site (the CGTCA motif). The 23-bp oligonucleotide designated AR1 from within the IL-6 enhancer region (-173 to -151) contains a CGTCA motif and bound nuclear proteins that also associated with c-fos oligonucleotides containing either an intact SRE or AP-1-like site. A single copy of AR1 inserted upstream of the herpesvirus TK promoter rendered this heterologous promoter inducible by IL-1 alpha, tumor necrosis factor, and serum as well as by activators of the protein kinase A (forskolin) and protein kinase C (phorbol ester) signal transduction pathways. Mutations in the AP-1-like site within AR1 (CGTCA----GTTCA) decreased inducibility of the chimeric IL-6/TK/chloramphenicol acetyltransferase gene by phorbol ester and by forskolin but not by serum, IL-1 alpha, or tumor necrosis factor. These data not only show that the AR1 segment from within the IL-6 enhancer binds nuclear proteins that also bind to c-fos regulatory elements but also demonstrate that a single copy of this 23-bp element is functionally sufficient to confer responsiveness to a variety of inducers and thus define a multiple-response element.


Genetics ◽  
2021 ◽  
Author(s):  
Takahiro Sakamoto ◽  
Hideki Innan

Abstract Muller’s ratchet is a process in which deleterious mutations are fixed irreversibly in the absence of recombination. The degeneration of the Y chromosome, and the gradual loss of its genes, can be explained by Muller’s ratchet. However, most theories consider single-copy genes, and may not be applicable to Y chromosomes, which have a number of duplicated genes in many species, which are probably undergoing concerted evolution by gene conversion. We developed a model of Muller’s ratchet to explore the evolution of the Y chromosome. The model assumes a non-recombining chromosome with both single-copy and duplicated genes. We used analytical and simulation approaches to obtain the rate of gene loss in this model, with special attention to the role of gene conversion. Homogenization by gene conversion makes both duplicated copies either mutated or intact. The former promotes the ratchet, and the latter retards, and we ask which of these counteracting forces dominates under which conditions. We found that the effect of gene conversion is complex, and depends upon the fitness effect of gene duplication. When duplication has no effect on fitness, gene conversion accelerates the ratchet of both single-copy and duplicated genes. If duplication has an additive fitness effect, the ratchet of single-copy genes is accelerated by gene duplication, regardless of the gene conversion rate, whereas gene conversion slows the degeneration of duplicated genes. Our results suggest that the evolution of the Y chromosome involves several parameters, including the fitness effect of gene duplication by increasing dosage and gene conversion rate.


2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Jennifer L Major ◽  
Maysoon Salih ◽  
Balwant S Tuana

The E2F/Pocket protein (Rb) pathway regulates cell growth, differentiation, and death by modulating gene expression. We previously examined this pathway in myocardium via manipulation of E2F6, which represses gene activity independently of Rb. Mice with cardiac specific expression of E2F6 develop dilated cardiomyopathy (DCM) without any signs of hypertrophic growth. We assessed the mechanisms of the apparent failure of compensatory growth as well as their response to the β-adrenergic agonist isoproterenol (iso). E2F6 transgenic (Tg) mice present with left ventricle dilation and significantly reduced ejection fraction as early as 2 weeks which persists into adulthood, but with no apparent increase in left ventricle weight: body weight (LVW:BW). E2F6-Tg mice treated with iso show double the increase in LVW: BW than their Wt counterparts (32% vs 16%, p-value: 0.007). Western blot revealed a specific activation of the β2-adrenergic pathway in Tg myocardium under basal conditions including a ~2-fold increase in β2-adrenergic receptors (β2-AR) (p-value: 8.9E-05), protein kinase A catalytic subunit (PKA-C) (p-value: 0.0176), activated c-SRC tyrosine-protein kinase (p-value: 0.0002), and an induction of the anti-apoptotic gene Bcl2. In contrast, a ~70% decrease in the cardiac growth regulator: AKT1 (p-value 0.0001) and a 4-fold increase in cyclic AMP dependent phosphodiesterase 4D (PDE4D), the negative regulator of PKA activity, was evident in Tg myocardium. The expression of E2F3 was de-regulated by E2F6, but was restored by iso while Rb expression was down-regulated. Thus deregulation of E2F/Rb pathway by E2F6 altered the β-adrenergic signaling pathway such that survival signaling was activated while hypertrophy was repressed resulting in the development of DCM without any increase in muscle mass. These data reveal a novel interplay between E2F and the β adrenergic pathway which regulate cardiac growth and fate.


1994 ◽  
Vol 14 (1) ◽  
pp. 10-20
Author(s):  
M Wu ◽  
C D Allis ◽  
M T Sweet ◽  
R G Cook ◽  
T H Thatcher ◽  
...  

Tetrahymena thermophila micronuclei contain four linker-associated proteins, alpha, beta, gamma, and delta. Synthetic oligonucleotides based on N-terminal protein sequences of beta and gamma were used to clone the micronuclear linker histone (MLH) gene. The MLH gene is single copy and is transcribed into a 2.4-kb message encoding all four linker-associated proteins. The message is translated into a polypeptide (Mic LH) that is processed at the sequence decreases RTK to give proteins whose amino acid sequences differ markedly from each other, from the sequence of macronuclear H1, and from sequences of typical H1s of other organisms. This represents the first example of multiple chromatin proteins derived from a single polyprotein. The delta protein consists largely of two high-mobility-group (HMG) boxes. An evolutionary analysis of HMG boxes indicates that the delta HMG boxes are similar to the HMG boxes of tsHMG, a protein that appears in elongating mouse spermatids when they condense and cease transcription, suggesting that delta could play a similar role in the micronucleus. The micronucleus divides mitotically, while the macronucleus divides amitotically. Surprisingly, macronuclear H1 but not Mic LH contains sequences resembling p34cdc2 kinase phosphorylation sites, while each of the Mic LH-derived proteins contains a typical protein kinase A phosphorylation site in its carboxy terminus.


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