Additional file 1: Figure S1. Multiple sequence alignment of LcRRP40. The full sequence of LcRRP40 and its putative orthologs from Xenopus and human were aligned. Numbers correspond to amino acid position in each protein. Proteins access numbers: Xt (Xenopus tropicalis—XP_002936379), Xl (Xenopus laevis—NP_001089320.1) and Hs (Homo sapiens—NP_057126.2). (*), identity; (:), strong similarity; (.), weak similarity. The amino acids residues involved in the RNA interactions, in the subunits interactions and those that are possible targets of posttranslational modifications are highlighted. CLUSTAL Omega was used for the sequence alignment [15]. Figure S2. Multiple sequence alignment of LcRRP6. The full sequence of LcRRP6 and its putative orthologues from Xenopus and human were aligned. Numbers correspond to amino acid position in each protein. Proteins access numbers: Xt (Xenopus tropicalis—XP_012821790), Xl (Xenopus laevis—NP_001084822.1) and Hs (Homo sapiens—NP_001001998.1). (*), identity; (:), strong similarity; (.), weak similarity. The amino acids residues present in the active site and those that are probable targets of posttranslational modifications were highlighted. CLUSTAL Omega was used for the sequence alignment [15]. Figure S3. Multiple sequence alignment of LcRRP42. The full sequence of LcRRP42 and its putative orthologues from Xenopus and human were aligned. Numbers correspond to amino acid position in each protein. Proteins access numbers: Xt (Xenopus tropicalis—NP_001032342), Xl (Xenopus laevis—NP_001086766.1) and Hs (Homo sapiens—BC012831). (*), identity; (:), strong similarity; (.), weak similarity. The amino acids residues involved in the interactions with the hexamer and RRP4 were highlighted. CLUSTAL Omega was used for the sequence alignment [15]. Figure S4. Multiple sequence alignment of LcRRP43. The full sequence of LcRRP43 and its putative orthologs from Xenopus and human were aligned. Numbers correspond to amino acid position in each protein. Proteins access numbers: Xt (Xenopus tropicalis—NP_001007919), Xl (Xenopus laevis—NP_001079391.1) and Hs (Homo sapiens—NP_852480.1). (*), identity; (:), strong similarity; (.), weak similarity. The amino acids residues involved in the interactions with the hexamer and that are probably targets of posttranslational modifications were highlighted. CLUSTAL Omega was used for the sequence alignment [15]. Figure S5. Photomicrographs of seminiferous lobules of L. catesbeianus from summer group (A, B)...