Multimodel filament tracer

Dear Cryosparc developers,
it is common for helical assemblies to show a great diversity of symmetry within the same dataset. Currently, the way to improve the picking is to generate projections of an already obtained map, run filament tracer, and repeat for each symmetry. However this approach will tend to pick all types of tubes/filament, even if they do not match precisely the reference, and therefore an extensive cleaning is always required, with the risk of re-including different symmetries in the same subset, especially if tubes with same/close diameter have different symmetries. A good workaround would be to allow multimodel picking : by providing templates corresponding to different symmetries (either from 2D class averages that have been previously sorted, or best, from 2D projections of maps with different symmetries) as different inputs, the job would output filament traces for each of the input. This “competitive” cross-correlation would allow a much more efficient distinction between the different symmetries. To make this even more efficient, it would be possible to add parameters to ensure that filaments have a consistent assignment to one reference, to avoid for example having subsequent segments assigned to different symmetries. I ran tests, with good success, with a “running window” strategy, where in each window the assignment to a symmetry/templates was based on the majority of segments correlating best to those templates. This allow that a given filament has symmetry transitions : the result would then be that this filament is segmented in several filaments. Please do not hesitate if you want to discuss this topic more into details.

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I must be missing something… if you’re generating templates and picking against them, why can’t you just provide multiple sets of templates at the same time?

As long as you don’t use output from the same job twice, CryoSPARC allows multiple template inputs.

Oh, does it then produce multiple outputs corresponding to each set of templates ? That would be great. Do you know if it also takes into account the particularities of helices for filament tracing as I mention (consistency/persistency of CC along filaments, etc… ) ?

That it doesn’t do, that I’m aware of.

However I’m sure @rposert will have some way of using cryosparc-tools to sort through by filament-id vs matched template. :smiley: