Molecular underpinnings of the early brain developmental response to differential feeding in the honey bee Apis mellifera

miRNA‐34 and miRNA‐210 target hexamerin genes enhancing their differential expression during early brain development of honeybee (Apis mellifera) castes

“…Our previous transcriptomic results showed hex70b, hex70c and hex110 are more transcribed in the brains of L3 workers than in queens, with miR-34, miR-210 and miR-317 being the opposite at the same phase of larval development (Vieira et al, 2021). Here, we showed that our transcriptional analysis confirmed the differential expression of hex70b, hex70c and hex110 genes in the brain of worker and queen L3 larvae.…”

“…Interestingly, three genes of this set are hex70b, hex70c and hex110, all more highly transcribed in workers. We also showed that three miRNAs, miR-34, miR-210 and miR-317 (also present in the worker and royal jellies larvae receive, Guo et al, 2013), are in higher levels in the queens' brain than in the workers' at the same phase of larval development (Vieira et al, 2021). Here, we tested the hypothesis that the brain of workers expresses higher levels of hexamerins than that of queens during key phases of larval development and that this differential hexamerin genes expression is further enhanced by the repressing activity of miR-34, miR-210, and miR-317 in queens.…”

“…The hexamerin genes hex70b, hex70c and hex110 were revealed to be differentially transcribed in the brain of L3 honeybee larvae (q < 0.05). RNA-Seq experiments showed hex70b (ID 406117) is 41.53-fold, hex70c (ID 409354) 25.24-fold, and hex110 (ID 551648) 12.39-fold more transcribed in workers than in queens (hex70a, ID 726848, was not differentially transcribed between castes, q = 0.99; Vieira et al, 2021). Here, we set out to determine their transcription profile in the brain of key developmental phases of the larval stage, L3, L4, and L5F2.…”

“…The molecular promoters of this caste-specific brain development in honeybees are, however, already underway in previous larval phases. Transcriptomic analyses performed by our group revealed a set of differentially expressed genes in the L3 brains of queens and workers, which represents the early molecular response to the differential feeding female honeybees receive during larval development (Vieira et al, 2021). Interestingly, three genes of this set are hex70b, hex70c and hex110, all more highly transcribed in workers.…”

“…Moreover, at least one of the hexamerin genes, hex70b, whose protein seems to represent the typical storage hexamerin (Martins and Bitondi, 2012), has been suggested to participate in the differential caste development of honeybees, likely through inhibiting the morphogenetic activity of JH, like in R. flavipes (Zhou et al, 2006(Zhou et al, , 2007. HEX110 and HEX70a have recently gained more attention since reports of our group demonstrated not only their non-canonical tissue expression (Martins et al, 2011;Martins and Bitondi, 2016;Paula Junior et al, 2021;Vieira et al, 2021), but also suggested they Lines highlighted in grey: used in the quantitative PCR assays. Time (in hours) after larva eclosion.…”