An Unexpectedly Complex Mitoribosome in Andalucia godoyi, a Protist with the Most Bacteria-like Mitochondrial Genome.

The mitoribosome, as known from studies in model organisms, deviates considerably from its ancestor, the bacterial ribosome. Deviations include substantial reduction of the mitochondrial ribosomal RNA (mt-rRNA) structure and acquisition of numerous mitochondrion-specific (M) mitoribosomal proteins (mtRPs). A broadly accepted view assumes that M-mtRPs compensate for structural destabilization of mt-rRNA resulting from its evolutionary remodeling. Since most experimental information on mitoribosome makeup comes from eukaryotes having derived mitochondrial genomes and mt-rRNAs, we tested this assumption by investigating the mitochondrial translation machinery of jakobids, a lineage of unicellular protists with the most bacteria-like mitochondrial genomes. We report here proteomics analyses of the Andalucia godoyi small mitoribosomal subunit and in silico transcriptomic and comparative genome analyses of four additional jakobids. Jakobids have mt-rRNA structures that minimally differ from their bacterial counterparts. Yet, with at least 31 small subunit and 44 large subunit mtRPs, the mitoriboproteome of Andalucia is essentially as complex as that in animals or fungi. Furthermore, the relatively high conservation of jakobid sequences has helped to clarify the identity of several mtRPs, previously considered to be lineage-specific, as divergent homologs of conserved M-mtRPs, notably mS22 and mL61. The coexistence of bacteria-like mt-rRNAs and a complex mitoriboproteome refutes the view that M-mtRPs were ancestrally recruited to stabilize deviations of mt-rRNA structural elements. We postulate instead that the numerous M-mtRPs acquired in the last eukaryotic common ancestor allowed mt-rRNAs to pursue a broad range of evolutionary trajectories across lineages: from dramatic reduction to acquisition of novel elements to structural conservatism.

Genetic analysis for carrier diagnosis in hemophilia A and B in the Mexican population: 25 years of experience.

Our 25 years of experience in carrier diagnosis of hemophilia A (HA) and B (HB) in Mexican population comprises linkage analysis of intragenic F8/F9 neutral variants along with, in severe HA (SHA), detection of F8 int22h and int1h inversions. In symptomatic carriers (SCs) we explored Lyonization to explain their symtomatology. From a DNA-Bank of 3,000 samples, intragenic restriction fragment length (RFLPs) and short tandem repeats (STRs) of F8/F9 genes were assessed by PCR-PAGE and GeneScan. In SHA patients, F8 inversions were detected by inverse shifting-PCR/diagnostic and complementary tests. In SCs, we evaluated hemorrhagic symptoms, clotting FVIII/FIX and X-chromosome inactivation (XCI) patterns were assessed by HUMARA assay and the search of XIST promoter pathogenic variants. Informativeness of linkage analysis for HA carrier diagnosis with RFLP's/STR's increased to 74% and reached 80% with five RFLPs for HB. Combined Inv22/Inv1 diagnosed 113 possible carriers, three de novo Inv22-1, and confirmed 45 mothers as obligate or sporadic carriers. Among 21 SCs, four showed extreme skewed XCI pattern (~80:20) but had normal karyotype and no C43G pathogenic variant in XIST promoter. Clotting FVIII/FIX correlated with the active X in leukocytes. Our data integrate the largest comprehensive research worldwide on the molecular diagnosis of HA and HB carriers in terms of the number of studied and diagnosed cases, in addition to the genetic analysis in SCs. Intragenic RFLPs and STRs of F8/F9 genes along with F8 int22h/int1h inversions in SHA emerge as optimal variants for molecular diagnosis in Mexican population. In counseling SCs, inheritance of skewed X-inactivation should be considered.

F8 inversions of introns 22 and 1 confer a moderate risk of inhibitors in Mexican patients with severe hemophilia A. Concordance analysis and literature review.

Intron-22 (Inv22) and intron-1 (Inv1) inversions account for approximately one half of all severe cases of hemophilia A (SHA) worldwide. Inhibitor development against exogenous factor VIII (FVIII) represents a major complication in HA. The causative F8 mutation is considered the most decisive factor conditioning inhibitor development. We aimed to investigate prevalence of Inv22 and Inv1 mutations, and its association as risk factors for developing inhibitors to FVIII. We investigated Inv22 and Inv1 in 255 SHA Mexican patients from 193 unrelated families using the inverse shifting-polymerase chain reaction (IS-PCR). We analyzed the association between inversions and inhibitor development via logistic regression introducing as covariates the populations, the inversions, F8-haplotypes and the age of patients at enrollment. Inv22 was found in 91/193 (47.2%: 38.9% exhibited Inv22-1 and 8.3% Inv22-2), and Inv1 in 2/193 (1.0%) independent families. Absolute inhibitor prevalence (IP) for Inv22 in unrelated patients was 15% (10-19). The cohorts and age of patients were independent predictors of inhibitor risk, but not inversions or haplotypes. Inversions presence in our population was associated to a moderate risk of developing inhibitors. Inv1 was found for the first time in two Mexican families. A relevant genetic component was observed by the strong concordance among brother-pairs.