Gene <Emphasis Type="Italic">angora</Emphasis> as a modifier of the <Emphasis Type="Italic">hairless</Emphasis> gene in mouse

The interaction between mouse angora-Y (Fgf5 ^go-Y) and hairless (hr) genes have been studied. Homozygous mutant gene Fgf5 ^go-Y increases length of all hair types, while homozygotes for the h gene lose hair completely starting on day 14 after birth. We obtained mice with genotypes +/+ hr/hr F₂, +/Fgf5 ^go-Y hr/hr and Fgf5 ^go-Y/Fgf5 ^go-Y hr/hr. Both +/Fgf5 ^go-Y hr/hr and +/+ hr/hr mice began to loose hair from their heads on day 14. This further extended on the whole body. On day 21 the mice were completely deprived of hair. Therefore a single dose of gene Fgf5 ^go-Y does not modify alopecia in mice homozygous for hr. However in double homozygotes Fgf5 ^go-Y/Fgf5 ^go-Y hr/hr alopecia started 4 days later, namely on day 18. It usually finished 10–12 days after detection of first bald patches. On days 28–30 double homozygotes lose coat completely. Hair loss in double homozygous mice was 1.5-fold slower than in +/+ hr/hr mice. This resulted from a significant extension of anagen phase induced by a mutant homozygous gene Fgf5 ^go-Y in morphogenesis of the hair follicle. The hr gene was expressed at the transmission phase from anagen to catagen. Our data shows that the angora gene is a modifier of the hairless gene and this results in a strong repression of alopecia progression in double homozygous mice compared to +/+ hr/hr animals.     

Four independent mutations in the feline fibroblast growth factor 5 gene determine the long-haired phenotype in domestic cats

To determine the genetic regulation of "hair length" in the domestic cat, a whole-genome scan was performed in a multigenerational pedigree in which the "long-haired" phenotype was segregating. The 2 markers that demonstrated the greatest linkage to the long-haired trait (log of the odds > or = 6) flanked an estimated 10-Mb region on cat chromosome B1 containing the Fibroblast Growth Factor 5 (FGF5) gene, a candidate gene implicated in regulating hair follicle growth cycle in other species. Sequence analyses of FGF5 in 26 cat breeds and 2 pedigrees of nonbreed cats revealed 4 separate mutations predicted to disrupt the biological activity of the FGF5 protein. Pedigree analyses demonstrated that different combinations of paired mutant FGF5 alleles segregated with the long-haired phenotype in an autosomal recessive manner. Association analyses of more than 380 genotyped breed and nonbreed cats were consistent with mutations in the FGF5 gene causing the long-haired phenotype in an autosomal recessive manner. In combination, these genomic approaches demonstrated that FGF5 is the major genetic determinant of hair length in the domestic cat.     

Interaction of mutant genes Fgf5go-Y, we, and wal changes the duration of hair growth cycles in mice

Mutant gene wallhaarig (wa) was acting as a modifier of the mutant gene waved alopecia (wal), substantially increasing hair loss rate in mice, as was previously shown in our laboratory. The current paper is devoted to a study of mutant gene angora-Y (Fgf5 ^go-Y ), which had extended anagen stage of the first and second generations hair growth cycles in triple heterozygotes (Fgf5 ^go-Y /Fgf5 ^go-Y we/we wal/wal). First generation guard hair in triple homozygotes had their anagen stage 4 days longer than the same stage in double homozygotes (+/+ we/we wal/wal). Hair loss started at a catagen stage in double homozygotes, while it started in triple homozygotes at the end of the same stage or even in a telogen. Such mutant gene interaction in hair follicle morphogenesis led to a partial recovery of a body hair coat in triple homozygotes.     

Gene angora as a modifier of the mouse hairless gene

The interactions between mouse angora-Y (Fgf5go-Y) and hairless (hr) genes have been studied. Homozygous mutant gene Fgf5go-Y increases hair length starting on day 14 after birth. We obtained mice with genotypes +/+ hr/hr F2, +/Fgf5go-Y hr/hr and Fgf5go-Y/Fgf5go-Y hr/hr. Both +/Fgf5go-Y hr/hr and +/+ hr/hr mice began to loose hair from their heads on day 14. This further extended on the whole body. On day 21 the mice were completely deprived of hair. Therefore a single dose of gene Fgf5go-Y does not affect alopecia mice homozygous for hr. However in double homozygotes Fgf5go-Y/Fgf5gO-hr/hr alopecia started 4 days later, namely on day 18. It usually finished 10-12 days after detection of first bald patches. On days 28-30 double homozygotes have lost all the hair. Hair loss in double homozygous mice was 1,5-fold slower than in +/+ hr/hr mice. This resulted from a significant extension of anagen phase induced by a mutant homozygous gene Fgf5go-Y in morphogenesis of the hair follicle. In contrast, hr gene was expressed only at the transmission phase from anagen to catagen. Our data shows that the angora gene is a modifier of the hairless gene and this results in a strong repression of alopecia progression in double homozygous mice compared to +/+ hr/hr animals.     

Allelic heterogeneity of FGF5 mutations causes the long‐hair phenotype in dogs

Hitherto, the only known mutant gene leading to the long‐hair phenotype in mammals is the fibroblast growth factor 5 (FGF5). In many dog breeds, the previously discovered FGF5:p.Cys95Phe mutation appeared completely concordant with the long‐hair phenotype, but for some breeds, the long‐hair phenotype could not be resolved. First, we studied the role of the FGF5:p.Cys95Phe and FGF5:g.145_150dupACCAGC mutations in 268 dogs descending from 27 breeds and seven wolves. As these mutations did not explain all the long‐hair phenotypes, all exons and their neighbouring regions of FGF5 were re‐sequenced. We detected three novel mutations in the coding sequence and one novel non‐coding splice‐site mutation in FGF5 associated with the long‐hair phenotype. The FGF5:p.Ala193Val polymorphism was perfectly consistent with long hair in Akitas and probably in Siberian huskies, too. Dogs of the long‐hair breed Samoyed were either homozygous or compound heterozygous for the FGF5:p.Ala193Val or the FGF5:p.Cys95Phe polymorphisms respectively. The two newly detected polymorphisms FGF5:c.559_560dupGG and FGF5:g.8193T>A and the known mutation FGF5:p.Cys95Phe explained the long‐hair phenotype of all Afghan hounds analysed. An FGF5:c.556_571del16 mutation was found in one longhaired Eurasier. All long‐hair‐associated mutations follow a recessive mode of inheritance, and allelic heterogeneity was a common finding in breeds other than Akita.     

Ablation of low-molecular-weight FGF2 isoform accelerates murine osteoarthritis while loss of high-molecular-weight FGF2 isoforms offers protection

FGF2 is an essential growth factor implicated in osteoarthritis (OA), and deletion of full-length FGF2 (Fgf2^ALLKO) leads to murine OA. However, the FGF2 gene encodes both high-molecular-weight (HMW) and low-molecular-weight (LMW) isoforms, and the effects of selectively ablating individual isoforms, as opposed to total FGF2, has not been investigated in the context of OA. We undertook this study to examine whether mice lacking HMW FGF2 (Fgf2^HMWKO) or LMW FGF2 (Fgf2^LMWKO) develop OA and to further characterize the observed OA phenotype in Fgf2^ALLKO mice. Fgf2^HMWKO mice never developed OA, but 6- and 9-month-old Fgf2^LMWKO and Fgf2^ALLKO mice displayed signs of OA, including eroded articular cartilage, altered subchondral bone and trabecular architecture, and increased OA marker enzyme levels. Even with mechanical induction of OA, Fgf2^HMWKO mice were protected against OA, whereas Fgf2^LMWKO and Fgf2^ALLKO displayed OA-like changes of the subchondral bone. Before exhibiting OA symptoms, Fgf2^LMWKO or Fgf2^ALLKO joints displayed differential expression of genes encoding key regulatory proteins, including interleukin-1β, insulin-like growth factor 1, bone morphogenetic protein 4, hypoxia-inducible factor 1, B-cell lymphoma 2, Bcl2-associated X protein, a disintegrin and metalloproteinase with thrombospondin motifs 5, ETS domain-containing protein, and sex-determining region Y box 9. Moreover, Fgf2^LMWKO OA cartilage exhibited increased FGF2, FGF23, and FGFR1 expression, whereas Fgf2^HMWKO cartilage had increased levels of FGFR3, which promotes anabolism in cartilage. These results demonstrate that loss of LMW FGF2 results in catabolic activity in joint cartilage, whereas absence of HMW FGF2 with only the presence of LMW FGF2 offers protection from OA.     

Gene angora enhances the effects of gene waved alopecia in mouse

Interaction between the mutant gene angora-Y (Fgf5 ^go-Y ) and the mutant gene waved alopecia (wal) in mice has been studied. Gene Fgf5 ^go-Y in a homozygous state increases the length of hair of all types, whereas the homozygotes for the wal gene display a waved hair with subsequent development of partial alopecia. Crosses between Fgf5 ^go-Y /Fgf5 ^go-Y and wal/wal mice gave the animals displaying the genotypes +/Fgf5 ^go-Y wal/wal and Fgf5 ^go-Y /Fgf5 ^go-Y wal/wal as well as F₂ +/+ wal/wal mice. The first signs of alopecia in F₂ +/+ wal/wal appear at the same time as in the mutant wal/wal BALB/c mice. This demonstrates that the genetic background has no effect on the expression of mutant gene wal. A single dose of gene +/Fgf5 ^go-Y in +/Fgf5 ^go-Y wal/wal mice causes a considerably earlier appearance of the first signs of alopecia compared with the +/+ wal/wal single homozygotes. The signs of alopecia in double homozygotes Fgf5 ^go-Y /Fgf5 ^go-Y wal/wal appear earlier than in the mice +/Fgf5 ^go-Y wal/wal. By the end of the first month after birth, the majority of double homozygotes have a virtually bold back with preserved scarce long hairs, guard hairs. Alopecia covers also the sides and belly. However, the head retains its hair and the regions of thinned long hairs remain on the limbs and near the tail base. The data obtained demonstrate that gene Fgf5 ^go-Y is a modifier of gene wal, as it enhances considerably the effect of gene wal. This appears in an earlier development of alopecia and its more pronounced progress in the mice with genotypes +/Fgf5 ^go-Y wal/wal and, particularly, Fgf5 ^go-Y /Fgf5 ^go-Y wal/wal.     

The effect of aluminium concentration on root hairs in white clover (Trifolium repens L.)

The effect of aluminium (Al) on root hair length and number is quantified using solution culture techniques with genotypes from white clover cultivar Tamar, that had previously been selected for long and short root hairs. The population differences were maintained in control (0 Al) treatments, with the long-haired population having hairs three times longer than the short-haired population. At an activity of 2.2 µM Al³⁺, root hair length decreased in both populations, the magnitude of the decrease being greater for the long-haired population. Root hair numbers decreased in a similar manner for both populations. At an activity of 4.4 µM Al³⁺ or higher, root hairs virtually disappeared and root growth was very stunted. The effect of Al on root hair development has not been previously quantified, however other workers have observed reduced root hair development in other species at activities of Al greater than 2.5 µM Al³⁺.     

The long and the short of it: evidence that FGF5 is a major determinant of canine 'hair'-itability

Hair length in dogs has been known for many years to be primarily controlled by a limited number of genes, but none of the genes have been identified. One of these genes produces a recessively inherited long-haired phenotype that has been thought to explain the bulk of hair-length variation among many breeds. Sequence analysis of the FGF5 gene in short and long-haired corgis resulted in the identification of two coding region differences: a duplication in a relatively non-conserved region of the gene and a missense mutation, resulting in the substitution of Phe for Cys, in a highly conserved region. Genotyping of 218 dogs from three breeds fixed for long hair, eight breeds fixed for short hair and five breeds in which long hair is segregating provided evidence that the missense mutation is associated with the hair-length differences among these breeds.     

Telogen elongation in the hair cycle of ob/ob mice

Alopecia impairs the physical and mental health of patients. We have previously shown that 8-week-old ob/ob mice have no reactivity to depilation, which is a stimulus that induces anagen transition in normal mice, while no hair cycle abnormalities have been reported in other studies until mice reach 7 weeks of age. Therefore, we hypothesized that ob/ob mice have abnormalities in hair cycle progression beyond 7 weeks of age. We examined 6- to 24-week-old ob/ob and 6- to 10-week-old normal mice. After acclimation, the dorsal skin was harvested and the hair cycle phase was identified histologically and immunohistochemically. Normal mice showed catagen–telogen and telogen–anagen transitions at 6 and 8–9 weeks old, respectively. In contrast, the anagen–catagen transition was observed in 7-week-old mice and the telogen phase was maintained from 10 to 24 weeks in most ob/ob mice. These results suggests that ob/ob mice are a possible model animal for telogen effluvium.     

Nuclear Isoforms of Fibroblast Growth Factor 2 Are Novel Inducers of Hypophosphatemia via Modulation of FGF23 and KLOTHO

FGF2 transgenic mice were developed in which type I collagen regulatory sequences drive the nuclear high molecular weight FGF2 isoforms in osteoblasts (TgHMW). The phenotype of TgHMW mice included dwarfism, decreased bone mineral density (BMD), osteomalacia, and decreased serum phosphate (P_i). When TgHMW mice were fed a high P_i diet, BMD was increased, and dwarfism was partially reversed. The TgHMW phenotype was similar to mice overexpressing FGF23. Serum FGF23 was increased in TgHMW mice. Fgf23 mRNA in bones and fibroblast growth factor receptors 1c and 3c and Klotho mRNAs in kidneys were increased in TgHMW mice, whereas the renal Na⁺/P_i co-transporter Npt2a mRNA was decreased. Immunohistochemistry and Western blot analyses of TgHMW kidneys showed increased KLOTHO and decreased NPT2a protein. The results suggest that overexpression of HMW FGF2 increases FGF23/FGFR/KLOTHO signaling to down-regulate NPT2a, causing P_i wasting, osteomalacia, and decreased BMD. We assessed whether HMW FGF2 expression was altered in the Hyp mouse, a mouse homolog of the human disease X-linked hypophosphatemic rickets/osteomalacia. Fgf2 mRNA was increased in bones, and Western blots showed increased FGF2 protein in nuclear fractions from osteoblasts of Hyp mice. In addition, immunohistochemistry demonstrated co-localization of FGF23 and HMW FGF2 protein in osteoblasts and osteocytes from Hyp mice. This study reveals a novel mechanism of regulation of the FGF23-P_i homeostatic axis.     

Bacterial leaf blight resistance genes (Xa21, xa13 and xa5) pyramiding through molecular marker assisted selection into rice cultivars

Marker assisted selection was employed to pyramid three bacterial blight resistance genes Xa21, xa13 and xa5 into high yielding susceptible rice cultivars ADT43 and ADT47. With the assistance of PCR markers, homozygous and heterozygous genotypes were identified in F₂ generation of two crosses (ADT43 × IRBB60 and ADT47 × IRBB60) and goodness of fit was tested. Eighty nine plants from F₃ generation of ADT43 × IRBB60 were also screened for resistance genes. The genotypes carrying resistance genes in different combinations were identified. The pyramided lines showed a wider spectrum and higher level of resistance against two Xoo isolates under field conditions.     

Genetic variation at hair length candidate genes in elephants and the extinct woolly mammoth

Background  

Like humans, the living elephants are unusual among mammals in being sparsely covered with hair. Relative to extant elephants, the extinct woolly mammoth, Mammuthus primigenius, had a dense hair cover and extremely long hair, which likely were adaptations to its subarctic habitat. The fibroblast growth factor 5 (FGF5) gene affects hair length in a diverse set of mammalian species. Mutations in FGF5 lead to recessive long hair phenotypes in mice, dogs, and cats; and the gene has been implicated in hair length variation in rabbits. Thus, FGF5 represents a leading candidate gene for the phenotypic differences in hair length notable between extant elephants and the woolly mammoth. We therefore sequenced the three exons (except for the 3' UTR) and a portion of the promoter of FGF5 from the living elephantid species (Asian, African savanna and African forest elephants) and, using protocols for ancient DNA, from a woolly mammoth.     

Scraggly, a new hair loss mutation on mouse Chromosome 19

By use of chlorambucil, we have generated a mouse mutation called scraggly (sgl) that exhibits skin and hair defects. Homozygous mutant mice exhibit hair loss, skin defects, and abnormalities in sebaceous lipid composition. We have constructed a high-resolution genetic map of mouse Chromosome (Chr) 19 that links this mutation to the anonymous DNA marker D19Umi1. An additional cross, (BALB/c × CAST/Ei) F₁× BALB/c, was used to map markers around this mutation as well as to map the potential candidate genes, Fgf8 and Cyp17. Allelism tests between sgl and asebia (ab), another hair loss mutation on mouse Chr 19, showed that these genes were separate and distinct. Received: 8 December 1998 / Accepted: 10 May 1999     

Fgf3‐Fgf4‐cis: A new mouse line for studying Fgf functions during mouse development

The fibroblast growth factor (FGF) family consists of 22 ligands in mice and humans. FGF signaling is vital for embryogenesis and, when dysregulated, can cause disease. Loss‐of‐function genetic analysis in the mouse has been crucial for understanding FGF function. Such analysis has revealed that multiple Fgfs sometimes function redundantly. Exploring such redundancy between Fgf3 and Fgf4 is currently impossible because both genes are located on chromosome 7, about 18.5 kb apart, making the frequency of interallelic cross‐over between existing mutant alleles too infrequent to be practicable. Therefore, we retargeted Fgf3 and Fgf4 in cis, generating an Fgf3 null allele and a conditional Fgf4 allele, subject to Cre inactivation. To increase the frequency of cis targeting, we used an F1 embryonic stem cell line that contained 129/SvJae (129) and C57BL/6J (B6) chromosomes and targeting constructs isogenic to the 129 chromosome. We confirmed cis targeting by assaying for B6/129 allele‐specific single‐nucleotide polymorphisms. We demonstrated the utility of the Fgf3^Δ‐Fgf4^flox‐cis mouse line by showing that the caudal axis extension defects found in the Fgf3 mutants worsen when Fgf4 is also inactivated. This Fgf3^Δ‐Fgf4^flox‐cis line will be useful to study redundancy of these genes in a variety of tissues and stages in development. genesis 54:91–98, 2016. Published 2016. This article is a US Government work and is in the public domain in the USA.     

FGF10/FGFR2b signaling plays essential roles during in vivo embryonic submandibular salivary gland morphogenesis

Background  

Analyses of Fgf10 and Fgfr2b mutant mice, as well as human studies, suggest that FGF10/FGFR2b signaling may play an essential, nonredundant role during embryonic SMG development. To address this question, we have analyzed the SMG phenotype in Fgf10 and Fgfr2b heterozygous and null mutant mice. In addition, although previous studies suggest that the FGF10/FGFR2b and FGF8/FGFR2c signaling pathways are functionally interrelated, little is known about the functional relationship between these two pathways during SMG development. We have designed in vivo and in vitro experiments to address this question.     

Redundant and dosage sensitive requirements for Fgf3 and Fgf10 in cardiovascular development

Heart development requires contributions from, and coordinated signaling interactions between, several cell populations, including splanchnic and pharyngeal mesoderm, postotic neural crest and the proepicardium. Here we report that Fgf3 and Fgf10, which are expressed dynamically in and near these cardiovascular progenitors, have redundant and dosage sensitive requirements in multiple aspects of early murine cardiovascular development. Embryos with Fgf3^−/+;Fgf10^−/−, Fgf3^−/−;Fgf10^−/+ and Fgf3^−/−;Fgf10^−/− genotypes formed an allelic series of increasing severity with respect to embryonic survival, with double mutants dead by E11.5. Morphologic analysis of embryos with three mutant alleles at E11.5–E13.5 and double mutants at E9.5–E11.0 revealed multiple cardiovascular defects affecting the outflow tract, ventricular septum, atrioventricular cushions, ventricular myocardium, dorsal mesenchymal protrusion, pulmonary arteries, epicardium and fourth pharyngeal arch artery. Assessment of molecular markers in E8.0–E10.5 double mutants revealed abnormalities in each progenitor population, and suggests that Fgf3 and Fgf10 are not required for specification of cardiovascular progenitors, but rather for their normal developmental coordination. These results imply that coding or regulatory mutations in FGF3 or FGF10 could contribute to human congenital heart defects.     

Interaction of mutant genes Fgf5(go-Y), we, and wal changes the duration of hair growth cycles in mice

Mutant gene wallhaarig (wa) was acting as a modifier of the mutant gene waved alopecia (wal), substantially increasing hair loss rate in mice, as was previously shown in our laboratory. The current paper is devoted to a study of mutant gene angora- Y(Fgf5(go-Y)), which had extended anagen stage of the first and second generations hair growth cycles in triple heterozygotes (Fgf5(go-Y)/Fgf5(go-Y) we/we wal/wal). First generation guard hair in triple homozygotes had their anagen stage 4 days longer than the same stage in double homozygotes (+/+ we/we wal/wal). Hair loss started at a catagen stage in double homozygotes, while it started in triple homozygotes at the end of the same stage or even in a telogen. Such mutant gene interaction in hair follicle morphogenesis led to a partial recovery of a body hair coat in triple homozygotes.     

An anatomical subject-specific FE-model for hip fracture load prediction

In order to reduce the socio-economic burden induced by osteoporotic hip fractures, finite element models have been evaluated as an additional diagnostic tool for fracture prediction. For a future clinical application, the challenge is to reach the best compromise between model relevance and computing time. Based on this consideration, the current study focused on the development and validation of a subject-specific FE-model using an original parameterised generic model and a specific personalization method. A total of 39 human femurs were tested to failure under a quasi-static compression in stance configuration. The corresponding FE-models were generated and for each specimen the numerical fracture load (F _FEM) was compared with the experimental value (F _EXP), resulting in a significant correlation (F _EXP = 1.006 F _FEM with r ² = 0.87 and SEE = 1220 N, p < 0.05) obtained with a reasonable computing time (30 mn). Further in vivo study should confirm the ability of this FE-model to improve the fracture risk prediction.