Case report of whole genome sequencing in the XY female: identification of a novel <Emphasis Type="Italic">SRY</Emphasis> mutation and revision of a misdiagnosis of androgen insensitivity syndrome

Background

The 46,XY female is characterised by a male karyotype and female phenotype arising due to any interruption in the sexual development pathways in utero. The cause is usually genetic and various genes are implicated.

Case presentation

Herein we describe a 46,XY woman who was first diagnosed with androgen insensitivity syndrome (testicular feminisation) at 18 years; however, this was later questioned due to the presence of intact Müllerian structures. The clinical phenotype suggested several susceptibility genes including SRY, DHH, NR5A1, NR0B1, AR, AMH, and AMHR2. To study candidate genes simultaneously, we performed whole genome sequencing. This revealed a novel and likely pathogenic missense variant (p.Arg130Pro, c.389G>C) in SRY, one of the major genes implicated in complete gonadal dysgenesis, hence securing this condition over androgen insensitivity syndrome as the cause of the patient’s disorder of sexual development.

Conclusion

This case highlights the emerging clinical utility of whole genome sequencing as a tool in differentiating disorders of sexual development.

     

A hypomorphic mutation of the gamma-1 adaptin gene (<Emphasis Type="Italic">Ap1g1</Emphasis>) causes inner ear,retina, thyroid,and testes abnormalities in mice

Adaptor protein (AP) complexes function in the intracellular sorting and vesicular transport of membrane proteins. The clathrin-associated AP-1 complex functions at the trans-Golgi network and endosomes, and some forms of this complex are thought to mediate the sorting of proteins in plasma membranes of polarized epithelial cells. A null mutation of the mouse Ap1g1 gene, which encodes the gamma-1 subunit of the AP-1 complex, causes embryonic lethality when homozygous, indicating its critical importance in early development but precluding studies of its possible roles during later stages. Here, we describe our analyses of a new spontaneous mutation of Ap1g1 named “figure eight” (symbol fgt) and show that it is an in-frame deletion of 6 bp, which results in the elimination of two amino acids of the encoded protein. In contrast to Ap1g1 ^?/? null mice, mice homozygous for the recessive fgt mutation are viable with adult survival similar to controls. Although Ap1g1 is ubiquitously expressed, the phenotype of Ap1g1 ^fgt mutant mice is primarily restricted to abnormalities in sensory epithelial cells of the inner ear, pigmented epithelial cells of the retina, follicular epithelial cells of the thyroid gland, and the germinal epithelium of the testis, suggesting that impaired AP-1 sorting and targeting of membrane proteins in these polarized cells may underlie the observed pathologies. Ap1g1 ^fgt mutant mice provide a new animal model to study the in vivo roles of gamma-1 adaptin and the AP-1 complex throughout development and to investigate factors that underlie its associated phenotypic abnormalities.     

Comparison <Emphasis Type="Italic">CCR5del32</Emphasis> Mutation in the <Emphasis Type="Italic">CCR5</Emphasis> Gene Frequencies in Russians,Tuvinians, and in Groups of HIV-Infected Individuals

The 32-bp deletion (CCR5del32 mutation) in the CCR5 (chemokine (C-C motif) receptor 5) gene, encoding CCR5 chemokine receptor, is one of the factors determining natural resistance to human immunodeficiency virus (HIV-1) infection. In the present study, the samples of Russians (n = 102), Tuvinians (n = 50), and HIV-infected individuals (n = 107) were examined for the presence of CCR5del32 mutation in the CCR5 gene. The CCR5del32 allele frequency in Russians and Tuvinians constituted 7.84 and 2%, respectively. Among HIV-1 infected individuals, two groups, of macrophage-tropic HIV-1 strain- and T-cell-tropic HIV-1 strain-infected were distinguished. The CCR5del32 allele frequency in the first group (6.45%) was lower than in the second one (8.73%). Statistical treatment of the HIV-1 infected individuals typing data showed that the difference in the CCR5del32 allele frequencies between the groups of sexually (macrophage-tropic) and parenterally (T-cell-tropic) infected individuals observed was within the limit of random deviation.     

The homologous identification of the stem rust resistance genes <Emphasis Type="Italic">Rpg5</Emphasis>, <Emphasis Type="Italic">Adf3</Emphasis> and <Emphasis Type="Italic">RGA1</Emphasis> in the relatives of barley

The barley genes Rpg5, RGA1 and Adf3, which provide a strong resistance to many pathotypes of stem rust, were cloned a few years ago, but it was still unclear whether their homologues were represented in wheat and in related species. The paper describes the results of a bioinformatic research to determine the homologues of Rpg5, RGA1 and Adf3 in the genomes of Triticum aestivum and several wild grasses, which breeders usually use as sources of stem rust resistance, and which are available in the genome databases. It was found that the Th. elongatum sequence Q9FEC6 and T. aestivum sequence Q43655 were the highly identical homologues of the Adf3 sequence. T. urartu M8A999 sequence and T. aestivum W5FCU1 sequence were found to be the closest homologues of Rpg5 complete protein sequence, but the identity of their kinase domains was not as clear as that of the other domains. The separate Rpg5 kinase part analysis did not provide the strong evidences that its orthologs were present in our corn species. T. urartu M7ZZX9 sequence and T. aestivum W5FFP0 and W5FI33 sequences were shown to be the homologues of RGA1. The analysis of the predicted active sites allowed finding out the difference between sequences of Rpg5, RGA1, Adf3 protein and their homologues.     

Inactivation of bone morphogenetic protein 1 (<Emphasis Type="Italic">Bmp1</Emphasis>) and tolloid-like 1 (<Emphasis Type="Italic">Tll1</Emphasis>) in cells expressing type I collagen leads to dental and periodontal defects in mice

Bone morphogenetic protein 1 (BMP1) and tolloid-like 1 (TLL1) belong to the BMP1/tolloid-like proteinase family, which cleaves secretory proteins. The constitutive deletion of the Bmp1 or Tll1 genes causes perinatal or embryonic lethality in mice. In this study, we first studied the β-galactosidase activity in mice in which an IRES-lacZ-Neo cassette was inserted in the intron of either the Bmp1 or the Tll1 gene; the β-galactosidase activities were used to reflect the expression of endogenous Bmp1 and Tll1, respectively. Our X-gal staining results showed that the odontoblasts in the tooth and cells in the periodontal ligament express both Bmp1 and Tll1. We then created Bmp1 ^flox/flox and Tll1 ^flox/flox mice by removing the IRES-lacZ-Neo cassette. By breeding 2.3 kb Col1a1-Cre mice with the Bmp1 ^flox/flox and Tll1 ^flox/flox mice, we further generated Col1a1-Cre;Bmp1 ^flox/flox ;Tll1 ^flox/flox mice in which both Bmp1 and Tll1 were inactivated in the Type I collagen-expressing cells. We employed X-ray radiography, histology and immunohistochemistry approaches to characterize the Col1a1-Cre;Bmp1 ^flox/flox ;Tll1 ^flox/flox mice. Our results showed that the molars of the Col1a1-Cre;Bmp1 ^flox/flox ;Tll1 ^flox/flox mice had wider predentin, thinner dentin and larger pulp chambers than those of the normal controls. The dentinal tubules of the molars in the Col1a1-Cre;Bmp1 ^flox/flox ;Tll1 ^flox/flox mice appeared disorganized. The level of dentin sialophosphoprotein in the molars of the 6-week-old Col1a1-Cre;Bmp1 ^flox/flox ;Tll1 ^flox/flox mice was lower than in the normal controls. The periodontal ligaments of the Col1a1-Cre;Bmp1 ^flox/flox ;Tll1 ^flox/flox mice were disorganized and had less fibrillin-1. Our findings indicate that the proteinases encoded by Bmp1 and Tll1 genes play essential roles in the development and maintenance of mouse dentin and periodontal ligaments.     

Analysis of <Emphasis Type="Italic">COQ2</Emphasis>gene in multiple system atrophy

Background

Loss of function COQ2 mutations results in primary CoQ10 deficiency. Recently, recessive mutations of the COQ2 gene have been identified in two unrelated Japanese families with multiple system atrophy (MSA). It has also been proposed that specific heterozygous variants in the COQ2 gene may confer susceptibility to sporadic MSA. To assess the frequency of COQ2 variants in patients with MSA, we sequenced the entire coding region and investigated all exonic copy number variants of the COQ2 gene in 97 pathologically-confirmed and 58 clinically-diagnosed MSA patients from the United States.

Results

We did not find any homozygous or compound heterozygous pathogenic COQ2 mutations including deletion or multiplication within our series of MSA patients. In two patients, we identified two heterozygous COQ2 variants (p.S54W and c.403?+?10G?>?T) of unknown significance, which were not observed in 360 control subjects. We also identified one heterozygous carrier of a known loss of function p.S146N substitution in a severe MSA-C pathologically-confirmed patient.

Conclusions

The COQ2 p.S146N substitution has been previously reported as a pathogenic mutation in primary CoQ10 deficiency (including infantile multisystem disorder) in a recessive manner. This variant is the third primary CoQ10 deficiency mutation observed in an MSA case (p.R387X and p.R197H). Therefore it is possible that in the heterozygous state it may increase susceptibility to MSA. Further studies, including reassessing family history in patients of primary CoQ10 deficiency for the possible occurrence of MSA, are now warranted to resolve the role of COQ2 variation in MSA.

     

Mutation Screening of the <Emphasis Type="Italic">CHCHD10</Emphasis> Gene in Chinese Patients with Amyotrophic Lateral Sclerosis

Mutations in the coiled-coil-helix-coiled-coil-helix domain-containing protein 10 gene (CHCHD10), involved in mitochondrial function, have recently been reported as a causative gene of amyotrophic lateral sclerosis (ALS). The aim of this study was to obtain the mutation prevalence of CHCHD10 and the phenotypes with mutations in Chinese ALS patients. A cohort of 499 ALS patients including 487 sporadic ALS (SALS) and 12 familial ALS (FALS), from the Department of Neurology, West China Hospital of Sichuan University, were screened for mutations of all exons of the CHCHD10 gene by Sanger sequencing. Novel candidate mutations or variants were confirmed by polymerase chain reaction-restriction fragment length polymorphism in 466 healthy individuals. All patients identified with mutations of CHCHD10 gene were screened for mutations of the common ALS causative genes including C9orf72, SOD1, TARDBP, FUS, PFN1, and SQSTM1. Three heterozygous variants, including two missense mutations (c.275A?>?G (p.Y92C) and c.306G?>?C (p.Q102H)) and a synonymous change c.306G?>?A (p.Q102Q), were found in exon 3 of CHCHD10 in three alive SALS individuals (with the longest disease duration of 8.6 years), all of which were not detected in healthy controls. No mutation in CHCHD10 was identified in FALS patients. No mutation was found in the aforementioned common ALS causative genes in the patients who carried CHCHD10 mutations. The mutation frequency of CHCHD10 (0.4 %, 2/487) in a Chinese SALS population suggests CHCHD10 gene mutation appears to be an uncommon cause of ALS in Chinese populations. CHCHD10 mutations are associated with a slow progression and long disease duration.     

<Emphasis Type="Italic">CENTB5</Emphasis> gene expression in humans and mice

Centaurin β5, a protein with a yet unknown function, belongs to the centaurin family. It is encoded by CENTB5, whose expression pattern has been studied insufficiently. Intron 14–15 of human CENTB5 contains a lowly variable minisatellite repeat UPS29, while the mouse Centb5 contains an imperfect microsatellite repeat (CATG)₁₉. The shorter UPS29 alleles have previously been associated with certain forms of Parkinson’s disease and epilepsy. Moreover, both human and murine CENTB5 are syntenic with SCNN1D and ACOT7, which are active primarily in the nervous system, and whose aberrations are associated with epilepsy and neurodegenerative processes. As intronic sequences can modulate the expression of not only those genes that harbor them, but also of neighboring and remote genes, the CENTB5, SCNN1D, and ACOT7 expression levels were all analyzed by RT-PCR. The potential of intronic tandem repeats UPS29 and (CATG)₁₉ to regulate/modulate the expression of CENTB5, SCNN1D, and ACOT7 has been assessed in silico. CENTB5, SCNN1D, and ACOT7 expression was detected in all human and murine tissues studied, suggestive of their physiologic importance. The putative role of UPS29 in the regulation of CENTB5, SCNN1D, and ACOT7 activity in the nerve tissue is discussed.     

BrFLC5: a weak regulator of flowering time in <Emphasis Type="Italic">Brassica rapa</Emphasis>

Key message

A splicing site mutation in BrFLC5, a non-syntenic paralogue of FLOWERING LOCUS C, was demonstrated to be related to flowering time variation in Brassica rapa.

Abstract

Flowering time regulation in Brassica rapa is more complex than in Arabidopsis, as there are multiple paralogues of flowering time genes in B. rapa. Brassica rapa contains four FLOWERING LOCUS C (FLC) genes, three of which are syntenic orthologues of AtFLC, while BrFLC5 is not. BrFLC1, BrFLC2, and BrFLC3 have been reported to be involved in flowering time regulation. However, BrFLC5 has thus far been deemed a pseudogene. We detected two alternative splicing patterns of BrFLC5 resulting from a nucleotide mutation (G/A) at the first nucleotide of intron 3 (named as Pi3+1(G/A)). Genotyping of BrFLC5Pi3?+?1(G/A) for 301 B. rapa accessions showed that this single nucleotide polymorphism was significantly related to flowering time variation (p?<?0.001). In the collection, the frequency of the functional G allele (35.2%) was much lower than that of the nonfunctional A allele (59.1%); however, the frequency of the G allele was very high among the turnips (83.6%). An F2 population segregating at this locus was developed to analyze the genetic effect of BrFLC5. The result showed that the G allele individuals began to bolt two days later than the A allele individuals, indicating that BrFLC5 is a weak regulator of flowering time. BrFLC5 was expressed at the lowest level among the three analyzed BrFLCs. The late allele (G allele) was dominant to the early allele (A allele) at the BrFLC5 locus, which was in contrast to that of BrFLC1 and BrFLC2. This characteristic suggests that BrFLC5 would be more efficient for breeding premature bolting resistance in B. rapa.

     

<Emphasis Type="Italic">CDKN2A</Emphasis> and <Emphasis Type="Italic">MC1R</Emphasis> variants found in Cypriot patients diagnosed with cutaneous melanoma

The prevalence of genetic variants associated to cutaneous melanoma (CM) has never been determined within Cypriot melanomas. This study evaluates the frequency of variants in cyclin-dependent kinase inhibitor 2A (CDKN2A) and melanocortin-1 receptor (MC1R) in 32 patients diagnosed with CM. Other characteristics and risk factors were also assessed. CDKN2A p.Ala148Thr was detected in three of 32 patients, while the control group revealed no variations within CDKN2A. MC1R screening in 32 patients revealed the following variations: p.Val60Leu in 11 patients, p.Arg142His in four patients, p.Thr314Thr in one patient, p.Arg160Trp in one patient, p.Val92Met/p.Thr314Thr in one patient and p.Val92Met/p.Arg142His/p.Thr314Thr in one patient. The control group revealed only p.Val60Leu (in 10 of 45 individuals), which is frequently found in general populations. Two unrelated patients carried CDKN2A p.Ala148Thr in combination with MC1R p.Arg142His, suggesting digenic inheritance that may provide evidence of different gene variants acting synergistically to contribute for CM development. This study confirms the presence of CDKN2A and MC1R variants among Cypriot melanomas and supports existing evidence of a role for these variants in susceptibility to melanoma.     

Two orthologs of late blight resistance gene <Emphasis Type="Italic">R1</Emphasis> in wild and cultivated potato

The R1 gene for resistance to oomycete Phytophthora infestans (Mont.) de Bary, the causal agent of late blight disease of potato (Solanum tuberosum L.), was initially identified in S. demissum and potato varieties bred by introgressing the S. demissum germplasm. Later a sequence characterized amplified region (SCAR) marker R1-1205 of this gene was also found in S. stoloniferum and S. polytrichon. Here we describe the full-length R1 sequence cloned from S. stoloniferum. This sequence is translatable, and this evidence of structural gene integrity is reinforced by functional characterization of the S. stoloniferum R1 gene in an effectoromics experiment. When screened across a series of S. demissum and S. stoloniferum accessions, the R1 sequences differed by several single nucleotide polymorphisms and an indel; this indel served the basis for constructing SCAR markers R1-517 and R1-513 that reliably discerned two R1 orthologs. The demissum-specific marker R1-517 was found in all S. demissum accessions under study; it was also present in many demissum-derived potato varieties and hybrids. The stoloniferum-specific marker R1-513 was found in 27% of S. stoloniferum and S. polytrichon accessions; however, we failed to discern this marker in the genotypes of cultivated potato listing S. stoloniferum in their pedigrees. Most probably, such absence of R1-513 is best explained by an opportunistic breeding history of stoloniferum-derived founder lines, which were employed first and foremost in breeding for resistance to potato virus Y: eventually, these founder lines are devoid of the R1 gene.     

A novel <Emphasis Type="Italic">PAX5</Emphasis> rearrangement in <Emphasis Type="Italic">TCF3-PBX1</Emphasis> acute lymphoblastic leukemia: a case report

Background

Chromosome translocations are a hallmark of B-cell precursor acute lymphoblastic leukemia (BCP-ALL). Additional genomic aberrations are also crucial in both BCP-ALL leukemogenesis and treatment management. Herein, we report the phenotypic and molecular cytogenetic characterization of an extremely rare case of BCP-ALL harboring two concomitant leukemia-associated chromosome translocations: t(1;19)(q23;q13.3) and t(9;17)(p13;q11.2). Of note, we described a new rearrangement between exon 6 of PAX5 and a 17q11.2 region, where intron 3 of SPECC1 is located. This rearrangement seems to disrupt PAX5 similarly to a PAX5 deletion. Furthermore, a distinct karyotype between diagnosis and relapse samples was observed, disclosing a complex clonal evolution during leukemia progression.

Case presentation

A 16-year-old boy was admitted febrile with abdominal and joint pain. At clinical investigation, he presented with anemia, splenomegaly, low white blood cell count and 92% lymphoblast. He was diagnosed with pre-B ALL and treated according to high risk GBTLI-ALL2009. Twelve months after complete remission, he developed a relapse in consequence of a high central nervous system and bone marrow infiltration, and unfortunately died.

Conclusions

To our knowledge, this is the first report of a rearrangement between PAX5 and SPECC1. The presence of TCF3-PBX1 and PAX5-rearrangement at diagnosis and relapse indicates that both might have participated in the malignant transformation disease maintenance and dismal outcome.

     

Filamentous Aggregation of Sequestosome-1/p62 in Brain Neurons and Neuroepithelial Cells upon <Emphasis Type="Italic">Tyr-Cre</Emphasis>-Mediated Deletion of the Autophagy Gene <Emphasis Type="Italic">Atg7</Emphasis>

Defects in autophagy and the resulting deposition of protein aggregates have been implicated in aging and neurodegenerative diseases. While gene targeting in the mouse has facilitated the characterization of these processes in different types of neurons, potential roles of autophagy and accumulation of protein substrates in neuroepithelial cells have remained elusive. Here we report that Atg7^f/f Tyr-Cre mice, in which autophagy-related 7 (Atg7) is conditionally deleted under the control of the tyrosinase promoter, are a model for accumulations of the autophagy adapter and substrate sequestosome-1/p62 in both neuronal and neuroepithelial cells. In the brain of Atg7^f/f Tyr-Cre but not of fully autophagy competent control mice, p62 aggregates were present in sporadic neurons in the cortex and other brain regions as well in epithelial cells of the choroid plexus and the ependyma. Western blot analysis confirmed a dramatic increase of p62 abundance and formation of high-molecular weight species of p62 in the brain of Atg7^f/f Tyr-Cre mice relative to Atg7^f/f controls. Immuno-electron microscopy showed that p62 formed filamentous aggregates in neurons and ependymal cells. p62 aggregates were also highly abundant in the ciliary body in the eye. Atg7^f/f Tyr-Cre mice reached an age of more than 2 years although neurological defects manifesting in abnormal hindlimb clasping reflexes were evident in old mice. These results show that p62 filaments form in response to impaired autophagy in vivo and suggest that Atg7^f/f Tyr-Cre mice are a model useful to study the long-term effects of autophagy deficiency on the homeostasis of different neuroectoderm-derived cells.     

Genetic associations between ADHD and dopaminergic genes (<Emphasis Type="Italic">DAT1</Emphasis> and <Emphasis Type="Italic">DRD4</Emphasis>) VNTRs in Korean children

It is well known that dopaminergic genes affect the development of attention deficit hyperactivity disorder (ADHD) in various populations. Many studies have shown that variable number tandem repeats (VNTRs) located within the 3′-untranslated region of DAT1 and in exon 3 of DRD4 are associated with ADHD development; however, these results were inconsistent. Therefore, we investigated the genetic association between two VNTRs and ADHD in Korean children. We determined the VNTRs using PCR. We examined genotype and allele frequency differences between the experimental and control groups, along with the odds ratios, using Chi square and exact tests. We observed a significant association between the children with ADHD and the control group in the 10R/10R genotype of DAT1 VNTRs (p?=?0.025). In addition, the 11R allele of DAT1 VNTRs showed a higher frequency in the control group than in the ADHD group (p?=?0.023). Also, the short repeat (without 11R) and long repeat alleles (including 11R) were associated with ADHD (p?<?0.05). The analysis of DRD4 VNTRs revealed that the 2R allele is associated with ADHD (p?=?0.025). A significant result was also observed in long and short repeats (p?<?0.05). Additionally, ADHD subtypes showed that the DRD4 VNTRs are associated with combined and hyperactive-impulsive subtype groups (p?<?0.05). Therefore, our results suggest that DAT1 VNTRs and DRD4 VNTRs play a role in the genetic etiology of ADHD in Korean children.     

Reliability of the search for 19 common mutations in the <Emphasis Type="Italic">CFTR</Emphasis> gene in Russian cystic fibrosis patients and the calculated frequency of the disease in Russian Federation

A study of Russian cystic fibrosis (CF) patient DNA was conducted to assess the incidence frequency of 19 mutations, namely CFTRdele2,3(21kb), F508del, I507del, 1677delTA, 2143delT, 2184insA, 394delTT, 3821delT, L138ins, 604insA, 3944delGT, G542X, W1282X, N1303K, R334W, and 3849 + 10kbC > T, S1196X, 621 + 1g > t, and E92K of the CFTR gene. We also sought to determine the estimated CF frequency in Russian Federation. In addition, we determined the total information content of the approach for 19 common mutations registration in the CFTR gene, 84.6%, and the allelic frequencies of the examined mutations: three mutations were observed with a frequency exceeding 5% (F508del, 53.98%, E92K, 6.47%, CFTRdele2,3(21kb), 5.35%); other mutations were observed with frequencies ranging from 0.13 to 3.0%. The CF population carrier frequency was 1 in 38 subjects, while the predicted CF frequency was 1 in 5776 newborns.     

The C-terminus of DSX<Superscript>F5</Superscript> protein acts as a novel regulatory domain in <Emphasis Type="Italic">Bombyx mori</Emphasis>

The doublesex gene regulates the somatic sexual development of Bombyx mori by alternatively splicing into sex-specific splice forms. In our previous study, the splice form Bmdsx ^F7 , which encodes the BmDSX^F5 protein, was found to be expressed in a female-specific manner and to contain a novel C-terminus. In this study, we aimed to investigate the role of this C-terminus. Two transgenic lines, L1 and L2, were constructed to ectopically express Bmdsx ^F7 in males. Phenotype and W chromosome-specific polymerase chain reaction (PCR) analysis showed that developmental abnormalities and sex reversal did not occur. Moreover, the sex ratio was also normal. Quantitative PCR revealed that the expression levels of SP1 and Vg were upregulated in the fat body of transgenic males. Additionally, the expression level of PBP was downregulated in the antenna of transgenic males. The results suggested that the C-terminus of BmDSX^F5 functioned as a regulatory domain during regulation of downstream target gene expression and that BmDSX^F5 participated in the sexual development of somatic cells together with other DSX proteins in B. mori.     

Rnq1 protein protects [<Emphasis Type="Italic">PSI</Emphasis><Superscript>+</Superscript>] prion from effect of the <Emphasis Type="Italic">PNM</Emphasis> mutation

The interaction of [PSI ⁺] and [PIN ⁺] factors in yeast Saccharomyces cerevisiae is known as the first evidence of prions networks. In [PIN ⁺] cells, Rnq1p prion aggregates work as a template for Sup35p aggregation, which is essential for [PSI ⁺] induction. No additional factors are required for subsequent Sup35p aggregation. Nevertheless, several recent reports provide data that indicate a more complex interplay between these prions. Our results show that the presence of Rnq1p in the cell significantly decreases the loss of [PSI ⁺] prion, which is caused by a double mutation in SUP35 (Q61K, Q62K substitutions in the Sup35 protein). These observations support the existence of interaction networks that converge on a strong linkage of prionogenic and prion-like proteins, and the participation of Rnq1 protein in the maintenance of prion [PSI ⁺].