3.6 | The significant expansion of the actin family in
Ascariasis and positive selection genes (PSGs) in B. schroederi
The migration of roundworms is the main cause of VLM (Fig. 4a). Actin
polymerization is controlled by intracellular signals that are mediated
by small GTPases of the Rho family (RhoA , Rac1 , andCdc42 ; Fig. 4c) (Ammassari-Teule & Segal, 2017). We observed a
very significant expansion of the actin family in the B.
schroederi genome (Fig. 3d). Surprisingly, the three upstream
regulators of actin (Rac1 , ROCK and MLCK ), were
under strong positive selection (P <0.01). ROCKphosphorylates the LIM-kinase which then phosphorylates cofilin to
promote rho-induced actin cytoskeleton reorganization (Maekawa & M.,
1999). These finding suggest a possible effect on myosin-actin
interaction. Using the branch-site model implemented in PAML, 475 genes
in the B. schroederi genome were found to be under strong
positive selection compared with other three roundworms (Supplementary
Data 3a). Compared with three roundworms, the acetylcholine receptor
subunit alpha-type deg-3 (P=6.5×10-3), which is an
important drug target (Jones, Davis, Hodgkin, & Sattelle, 2007), was
shown to be under strong positive selection in the B. schroederigenome (Supplementary Data 3a).