Telomerase is a reverse transcriptase complex that ensures stable maintenance of linear eukaryotic chromosome ends by overcoming the end replication problem, posed by the inability of replicative DNA polymerases to fully replicate linear DNA. The catalytic subunit TERT must be assembled properly with its telomerase RNA for telomerase to function, and studies in Tetrahymena have established that p65, a La-related protein 7 (LARP7) family protein, utilizes its C-terminal xRRM domain to promote assembly of the telomerase ribonucleoprotein (RNP) complex. However, LARP7-dependent telomerase complex assembly has been considered as unique to ciliates that utilize RNA polymerase III to transcribe telomerase RNA. Here we show evidence that fission yeast Schizosaccharomyces pombe utilizes the p65-related protein Pof8 and its xRRM domain to promote assembly of RNA polymerase II-encoded telomerase RNA with TERT. Furthermore, we show that Pof8 contributes to repression of the transcription of noncoding RNAs at telomeres.

Background The metabolic syndrome (MetS) is a collection of co-occurring complex disorders including obesity, hypertension, dyslipidemia, and insulin resistance. The Lyon Hypertensive (LH) and Lyon Normotensive (LN) rats are models of MetS sensitivity and resistance, respectively. To identify genetic determinants and mechanisms underlying MetS, an F2 intercross between LH and LN was comprehensively studied. Methods and Results Multi-dimensional data were obtained including genotypes of 1536 SNPs, 23 physiological traits and more than 150 billion nucleotides of RNA-seq reads from the livers of F2 intercross offspring and parental rats. Phenotypic and expression QTL were mapped. Application of systems biology methods identified 17 candidate MetS genes. Several putative causal cis-eQTL were identified corresponding with pQTL loci. We found an eQTL hotspot on rat chromosome 17 that is causally associated with multiple MetS-related traits, and found RGD1562963, a gene regulated in cis by this eQTL hotspot, as the most likely eQTL driver gene directly affected by genetic variation between LH and LN rats. Conclusions Our study sheds light on the intricate pathogenesis of MetS and demonstrates that systems biology with high-throughput sequencing is a powerful method to study the etiology of complex genetic diseases.

Hypertension is a major risk factor for cardiovascular disease, Type 2 diabetes, and end organ failure, and is often found concomitant with disorders characteristic of the Metabolic Syndrome (MetS), including obesity, dyslipidemia, and insulin resistance. While the associated features often occur together, the pathway(s) or mechanism(s) linking hypertension in MetS are not well understood. Previous work determined that genetic variation on rat chromosome 17 (RNO17) contributes to several MetS-defining traits (including hypertension, obesity, and dyslipidemia) in the Lyon Hypertensive (LH) rat, a genetically determined MetS model. We hypothesized that at least some of the traits on RNO17 are controlled by a single gene with pleiotropic effects. To address this hypothesis, consomic and congenic strains were developed, whereby a defined fragment of RNO17 from the LH rat was substituted with the control Lyon Normotensive (LN) rat, and MetS phenotypes were measured in the resultant progeny. Compared to LH rats, LH-17LN consomic rats have significantly reduced body weight, blood pressure, and lipid profiles. A congenic strain (LH-17LNc), with a substituted fragment at the distal end of RNO17 (17q12.3; 74–97 Mb; rn4 assembly), showed differences from the LH rat in blood pressure and serum total cholesterol and triglycerides. Interestingly, there was no difference in body weight between the LH-17LNc and the parental LH rat. These data indicate that blood pressure and serum lipids are regulated by a gene(s) in the distal congenic interval, and could be due to pleiotropy. The data also indicate that body weight is not determined by the same gene(s) at this locus. Interestingly, only two small haplotypes spanning a total of approximately 0.5 Mb differ between the LH and LN genomes in the congenic interval. Genes in these haplotypes are strong candidate genes for causing dyslipidemia in the LH rat. Overall, MetS, even in a simplified genetic model such as the LH-17LN rat, is likely due to both independent and pleiotropic gene effects.

The metabolic syndrome (MetS) is characterized by obesity, dyslipidemia, hypertension, and insulin resistance and is a major risk factor for cardiovascular disease. Using the Lyon Hypertensive and Lyon Normotensive rats as models of the metabolic syndrome, we aim to determine both physiological and transcriptional regulation underlying the syndrome. To identify genetic loci influencing phenotypes underlying MetS, an F2 intercross between LH and LN with 150 offspring was studied to identify physiological quantitative trait loci (pQTL) contributing to plasma lipid levels, blood pressure, and body weight/adiposity. We performed RNA-seq in livers from 36 selected rats from the intercross to identify the mapping of gene expression, or expression (e)QTL. Linkage analyses identified pQTL and eQTL with significant logarithm of odds (lod) scores, whose genome-wide significance was determined by permutation testing. We identified 17 pQTL on 5 rat chromosomes and 75 on 16 chromosomes. It has been determined that LH chromosome 17 contributes to multiple features of MetS; furthermore, an eQTL on rat chromosome 17 was identified that regulates the expression of multiple genes in trans, meaning the regulated gene falls outside the QTL interval or on another chromosome. We hypothesize these genes share a common transcriptional regulator which is affected by genetic variation on chromosome 17. eQTLs are likely to influence precursor pathways and cofactors of the metabolic syndrome. Identifying these in the LH rat could lead to translational studies to determine their role in the human MetS.

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