RT Journal Article
SR Electronic
T1 SPLIT HAND/FOOT VARIANTS FAIL TO RESCUE PRDM1A MUTANT CRANIOFACIAL DEFECTS
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2023.05.19.541469
DO 10.1101/2023.05.19.541469
A1 Brittany T. Truong
A1 Lomeli C. Shull
A1 Ezra Lencer
A1 Kristin B. Artinger
YR 2023
UL http://biorxiv.org/content/early/2023/05/22/2023.05.19.541469.abstract
AB Background Split Hand/Foot Malformation (SHFM) is a congenital limb disorder presenting with limb anomalies, such as missing, hypoplastic, or fused digits, and often craniofacial defects, including a cleft lip/palate, microdontia, micrognathia, or maxillary hypoplasia. We previously identified three novel variants in the transcription factor, PRDM1, that are associated with SHFM phenotypes. One individual also presented with a high arch palate. Studies in vertebrates indicate that PRDM1 is important for development of the skull; however, prior to our study, human variants in PRDM1 had not been associated with craniofacial anomalies.Methods Using transient mRNA overexpression assays in prdm1a-/- mutant zebrafish, we tested whether the PRDM1 SHFM variants were functional and could lead to a rescue of the craniofacial defects observed in prdm1a-/- mutants. We also mined a CUT&RUN and RNA-seq dataset to examine Prdm1a binding and the effect of Prdm1a loss on craniofacial genes.Results prdm1a-/- mutants exhibit craniofacial defects including a hypoplastic neurocranium, a loss of posterior ceratobranchial arches, a shorter palatoquadrate, and an inverted ceratohyal. Injection of wildtype hPRDM1 in prdm1a-/- mutants partially rescues these structures. However, injection of each of the three SHFM variants fails to rescue the skeletal defects. Loss of prdm1a leads to a decreased expression of important craniofacial genes, such as dlx5a/dlx6a, hand2, sox9b, col2a1a, and hoxb genes.Conclusion These data suggest that the three SHFM variants are not functional and may have led to the craniofacial defects observed in the humans. Finally, they demonstrate how Prdm1a can directly bind and regulate craniofacial gene expression.Competing Interest StatementThe authors have declared no competing interest.