Genomic multidisciplinary teams: A model for navigating genetic mainstreaming and precision medicine.

AIM: Recent rapid advances in genomics are revolutionising patient diagnosis and management of genetic conditions. However, this has led to many challenges in service provision, education and upskilling requirements for non-genetics health-care professionals and remuneration for genomic testing. In Australia, Medicare funding with a Paediatric genomic testing item for patients with intellectual disability or syndromic features has attempted to address this latter issue. The Sydney Children's Hospitals Network - Westmead (SCHN-W) Clinical Genetics Department established Paediatric and Neurology genomic multidisciplinary team (MDT) meetings to address the Medicare-specified requirement for discussion with clinical genetics, and increasing genomic testing advice requests. METHODS: This SCHN-W genomic MDT was evaluated with two implementation science frameworks - the RE-AIM (Reach, Effectiveness, Adoption, Implementation, Maintenance) and GMIR - Genomic Medicine Integrative Research frameworks. Data from June 2020 to July 2022 were synthesised and evaluated, as well as process mapping of the MDT service. RESULTS: A total of 205 patients were discussed in 34 MDT meetings, facilitating 148 genomic tests, of which 73 were Medicare eligible. This was equivalent to 26% of SCHN-W genetics outpatient activity, and 13% of all Medicare-funded paediatric genomic testing in NSW. 39% of patients received a genetic diagnosis. CONCLUSION: The genomic MDT facilitated increased genomic testing at a tertiary paediatric centre and is an effective model for mainstreaming and facilitating precision medicine. However, significant implementation issues were identified including cost and sustainability, as well as the high level of resourcing that will be required to scale up this approach to other areas of medicine.

Redß177 annealase structure reveals details of oligomerization and λ Red-mediated homologous DNA recombination.

The Redß protein of the bacteriophage λ red recombination system is a model annealase which catalyzes single-strand annealing homologous DNA recombination. Here we present the structure of a helical oligomeric annealing intermediate of Redß, consisting of N-terminal residues 1-177 bound to two complementary 27mer oligonucleotides, determined via cryogenic electron microscopy (cryo-EM) to a final resolution of 3.3 Å. The structure reveals a continuous binding groove which positions and stabilizes complementary DNA strands in a planar orientation to facilitate base pairing via a network of hydrogen bonding. Definition of the inter-subunit interface provides a structural basis for the propensity of Redß to oligomerize into functionally significant long helical filaments, a trait shared by most annealases. Our cryo-EM structure and molecular dynamics simulations suggest that residues 133-138 form a flexible loop which modulates access to the binding groove. More than half a century after its discovery, this combination of structural and computational observations has allowed us to propose molecular mechanisms for the actions of the model annealase Redß, a defining member of the Redß/RecT protein family.

Molecular basis for RNA polymerase-dependent transcription complex recycling by the helicase-like motor protein HelD.

In bacteria, transcription complexes stalled on DNA represent a major source of roadblocks for the DNA replication machinery that must be removed in order to prevent damaging collisions. Gram-positive bacteria contain a transcription factor HelD that is able to remove and recycle stalled complexes, but it was not known how it performed this function. Here, using single particle cryo-electron microscopy, we have determined the structures of Bacillus subtilis RNA polymerase (RNAP) elongation and HelD complexes, enabling analysis of the conformational changes that occur in RNAP driven by HelD interaction. HelD has a 2-armed structure which penetrates deep into the primary and secondary channels of RNA polymerase. One arm removes nucleic acids from the active site, and the other induces a large conformational change in the primary channel leading to removal and recycling of the stalled polymerase, representing a novel mechanism for recycling transcription complexes in bacteria.