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Nmf9 Encodes a Highly Conserved Protein Important to Neurological Function in Mice and Flies.

Zhang S, Ross KD, Seidner GA, Gorman MR, Poon TH, Wang X, Keithley EM, Lee PN, Martindale MQ, Joiner WJ, Hamilton BA - PLoS Genet. (2015)

Bottom Line: Homologous genes from unicellular organisms and invertebrate animals predict interactions with small GTPases, but the corresponding domains are absent in mammalian Nmf9.Intriguingly, homozygotes for mutations in the Drosophila homolog, CG45058, show profound locomotor defects and premature death, while heterozygotes show striking effects on sleep and activity phenotypes.These results link a novel gene orthology group to discrete neurological functions, and show conserved requirement across wide phylogenetic distance and domain level structural changes.

View Article: PubMed Central - PubMed

Affiliation: Biomedical Sciences Graduate Program, University of California, San Diego School of Medicine, La Jolla, California, United States of America.

ABSTRACT
Many protein-coding genes identified by genome sequencing remain without functional annotation or biological context. Here we define a novel protein-coding gene, Nmf9, based on a forward genetic screen for neurological function. ENU-induced and genome-edited mutations in mice produce deficits in vestibular function, fear learning and circadian behavior, which correlated with Nmf9 expression in inner ear, amygdala, and suprachiasmatic nuclei. Homologous genes from unicellular organisms and invertebrate animals predict interactions with small GTPases, but the corresponding domains are absent in mammalian Nmf9. Intriguingly, homozygotes for mutations in the Drosophila homolog, CG45058, show profound locomotor defects and premature death, while heterozygotes show striking effects on sleep and activity phenotypes. These results link a novel gene orthology group to discrete neurological functions, and show conserved requirement across wide phylogenetic distance and domain level structural changes.

No MeSH data available.


Related in: MedlinePlus

Mutant nmf9 animals show age and sex-dependent vestibular dysfunction.(A) Landing test showed increased frequency of rotation or curling by nmf9 homozygotes relative to control (+/+) littermates (Fisher's exact test, p = 1.9x10-8 between genotypes, 0.52 between sexes). (B) Forced swim test further showed vestibular dysfunction in nmf9 relative to littermates (Asymptotic logrank test, p = 9.5x10-8 for geneotype stratified by sex) with a greater performance difference in females (p = 0.017 for sex stratified by genotype) due to lower performance among control males. Red, control; pink, mutant females. Navy, control; blue, mutant males. (C) Circling by mutant animals also showed significant sex bias (Fisher’s exact test, p = 0.021) and age-dependent progression (p = 0.013) in frequency. Sample sizes apply to panels C-F. (D) Head nodding also supported progression (p = 0.0014), but not significant sex bias (p = 0.12). Although (E) hyperactivity and (F) tremor were pronounced in mutant animals, effects of sex and age on did not reach statistical significance.
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pgen.1005344.g001: Mutant nmf9 animals show age and sex-dependent vestibular dysfunction.(A) Landing test showed increased frequency of rotation or curling by nmf9 homozygotes relative to control (+/+) littermates (Fisher's exact test, p = 1.9x10-8 between genotypes, 0.52 between sexes). (B) Forced swim test further showed vestibular dysfunction in nmf9 relative to littermates (Asymptotic logrank test, p = 9.5x10-8 for geneotype stratified by sex) with a greater performance difference in females (p = 0.017 for sex stratified by genotype) due to lower performance among control males. Red, control; pink, mutant females. Navy, control; blue, mutant males. (C) Circling by mutant animals also showed significant sex bias (Fisher’s exact test, p = 0.021) and age-dependent progression (p = 0.013) in frequency. Sample sizes apply to panels C-F. (D) Head nodding also supported progression (p = 0.0014), but not significant sex bias (p = 0.12). Although (E) hyperactivity and (F) tremor were pronounced in mutant animals, effects of sex and age on did not reach statistical significance.

Mentions: The nmf9 mutation was recognized in a chemical mutagenesis screen based on tremor and vestibular phenotypes. In our evaluation, vestibular signs included circling, nodding, and head tilt (S1 Video) and abnormal landing and forced swim tests. Not every mutant was abnormal in every test, but all mutant animals were abnormal in at least one test and by visual inspection relative to co-isogenic non-mutant littermates. Visible head nodding, hyperactivity, and tremor were enhanced by light vertical acceleration or extended handling. In the landing test, animals were suspended by their tails and scored for trunk curling and attempts to rotate, rather than reaching for ground, by an investigator blinded to genotype. Mutant animals showed a significant increase in frequency of both trunk curling and rotation compared to littermate controls (Fig 1A). In the forced swim test, most control littermates swam with their snout above water for ≥1 min., while nmf9 mutants typically were unable to remain righted above the surface and had to be rescued before 30 sec. to prevent drowning (Fig 1B). Differences between genotypes were more pronounced in females than males for vestibular phenotypes. The frequency and severity of circling and head nodding in mutant animals increased progressively from 21 days to 6 months (Fig 1C and 1D), though hyperactivity and tremor did not (Fig 1E and 1F); these phenotypes were essentially absent from control littermates. Histologically, however, mutant animals had grossly normal inner ear structures and did not show hearing impairment (S1 Fig), suggesting a mature functional, rather than a gross morphological, basis for vestibular defects.


Nmf9 Encodes a Highly Conserved Protein Important to Neurological Function in Mice and Flies.

Zhang S, Ross KD, Seidner GA, Gorman MR, Poon TH, Wang X, Keithley EM, Lee PN, Martindale MQ, Joiner WJ, Hamilton BA - PLoS Genet. (2015)

Mutant nmf9 animals show age and sex-dependent vestibular dysfunction.(A) Landing test showed increased frequency of rotation or curling by nmf9 homozygotes relative to control (+/+) littermates (Fisher's exact test, p = 1.9x10-8 between genotypes, 0.52 between sexes). (B) Forced swim test further showed vestibular dysfunction in nmf9 relative to littermates (Asymptotic logrank test, p = 9.5x10-8 for geneotype stratified by sex) with a greater performance difference in females (p = 0.017 for sex stratified by genotype) due to lower performance among control males. Red, control; pink, mutant females. Navy, control; blue, mutant males. (C) Circling by mutant animals also showed significant sex bias (Fisher’s exact test, p = 0.021) and age-dependent progression (p = 0.013) in frequency. Sample sizes apply to panels C-F. (D) Head nodding also supported progression (p = 0.0014), but not significant sex bias (p = 0.12). Although (E) hyperactivity and (F) tremor were pronounced in mutant animals, effects of sex and age on did not reach statistical significance.
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pgen.1005344.g001: Mutant nmf9 animals show age and sex-dependent vestibular dysfunction.(A) Landing test showed increased frequency of rotation or curling by nmf9 homozygotes relative to control (+/+) littermates (Fisher's exact test, p = 1.9x10-8 between genotypes, 0.52 between sexes). (B) Forced swim test further showed vestibular dysfunction in nmf9 relative to littermates (Asymptotic logrank test, p = 9.5x10-8 for geneotype stratified by sex) with a greater performance difference in females (p = 0.017 for sex stratified by genotype) due to lower performance among control males. Red, control; pink, mutant females. Navy, control; blue, mutant males. (C) Circling by mutant animals also showed significant sex bias (Fisher’s exact test, p = 0.021) and age-dependent progression (p = 0.013) in frequency. Sample sizes apply to panels C-F. (D) Head nodding also supported progression (p = 0.0014), but not significant sex bias (p = 0.12). Although (E) hyperactivity and (F) tremor were pronounced in mutant animals, effects of sex and age on did not reach statistical significance.
Mentions: The nmf9 mutation was recognized in a chemical mutagenesis screen based on tremor and vestibular phenotypes. In our evaluation, vestibular signs included circling, nodding, and head tilt (S1 Video) and abnormal landing and forced swim tests. Not every mutant was abnormal in every test, but all mutant animals were abnormal in at least one test and by visual inspection relative to co-isogenic non-mutant littermates. Visible head nodding, hyperactivity, and tremor were enhanced by light vertical acceleration or extended handling. In the landing test, animals were suspended by their tails and scored for trunk curling and attempts to rotate, rather than reaching for ground, by an investigator blinded to genotype. Mutant animals showed a significant increase in frequency of both trunk curling and rotation compared to littermate controls (Fig 1A). In the forced swim test, most control littermates swam with their snout above water for ≥1 min., while nmf9 mutants typically were unable to remain righted above the surface and had to be rescued before 30 sec. to prevent drowning (Fig 1B). Differences between genotypes were more pronounced in females than males for vestibular phenotypes. The frequency and severity of circling and head nodding in mutant animals increased progressively from 21 days to 6 months (Fig 1C and 1D), though hyperactivity and tremor did not (Fig 1E and 1F); these phenotypes were essentially absent from control littermates. Histologically, however, mutant animals had grossly normal inner ear structures and did not show hearing impairment (S1 Fig), suggesting a mature functional, rather than a gross morphological, basis for vestibular defects.

Bottom Line: Homologous genes from unicellular organisms and invertebrate animals predict interactions with small GTPases, but the corresponding domains are absent in mammalian Nmf9.Intriguingly, homozygotes for mutations in the Drosophila homolog, CG45058, show profound locomotor defects and premature death, while heterozygotes show striking effects on sleep and activity phenotypes.These results link a novel gene orthology group to discrete neurological functions, and show conserved requirement across wide phylogenetic distance and domain level structural changes.

View Article: PubMed Central - PubMed

Affiliation: Biomedical Sciences Graduate Program, University of California, San Diego School of Medicine, La Jolla, California, United States of America.

ABSTRACT
Many protein-coding genes identified by genome sequencing remain without functional annotation or biological context. Here we define a novel protein-coding gene, Nmf9, based on a forward genetic screen for neurological function. ENU-induced and genome-edited mutations in mice produce deficits in vestibular function, fear learning and circadian behavior, which correlated with Nmf9 expression in inner ear, amygdala, and suprachiasmatic nuclei. Homologous genes from unicellular organisms and invertebrate animals predict interactions with small GTPases, but the corresponding domains are absent in mammalian Nmf9. Intriguingly, homozygotes for mutations in the Drosophila homolog, CG45058, show profound locomotor defects and premature death, while heterozygotes show striking effects on sleep and activity phenotypes. These results link a novel gene orthology group to discrete neurological functions, and show conserved requirement across wide phylogenetic distance and domain level structural changes.

No MeSH data available.


Related in: MedlinePlus