Differential expression of Meis2, Mab21l2 and Tbx3 during limb development associated with diversification of limb morphology in mammals

PLoS One. 2014 Aug 28;9(8):e106100. doi: 10.1371/journal.pone.0106100. eCollection 2014.

Abstract

Bats are the only mammals capable of self-powered flight using wings. Differing from mouse or human limbs, four elongated digits within a broad wing membrane support the bat wing, and the foot of the bat has evolved a long calcar that spread the interfemoral membrane. Our recent mRNA sequencing (mRNA-Seq) study found unique expression patterns for genes at the 5' end of the Hoxd gene cluster and for Tbx3 that are associated with digit elongation and wing membrane growth in bats. In this study, we focused on two additional genes, Meis2 and Mab21l2, identified from the mRNA-Seq data. Using whole-mount in situ hybridization (WISH) we validated the mRNA-Seq results for differences in the expression patterns of Meis2 and Mab21l2 between bat and mouse limbs, and further characterize the timing and location of the expression of these two genes. These analyses suggest that Meis2 may function in wing membrane growth and Mab21l2 may have a role in AP and DV axial patterning. In addition, we found that Tbx3 is uniquely expressed in the unique calcar structure found in the bat hindlimb, suggesting a role for this gene in calcar growth and elongation. Moreover, analysis of the coding sequences for Meis2, Mab21l2 and Tbx3 showed that Meis2 and Mab21l2 have high sequence identity, consistent with the functions of genes being conserved, but that Tbx3 showed accelerated evolution in bats. However, evidence for positive selection in Tbx3 was not found, which would suggest that the function of this gene has not been changed. Together, our findings support the hypothesis that the modulation of the spatiotemporal expression patterns of multiple functional conserved genes control limb morphology and drive morphological change in the diversification of mammalian limbs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • Chiroptera / anatomy & histology*
  • Chiroptera / embryology
  • Chiroptera / genetics
  • Conserved Sequence
  • Embryo, Mammalian / anatomy & histology
  • Extremities / growth & development*
  • Eye Proteins / genetics*
  • Female
  • Gene Expression Regulation, Developmental
  • Humans
  • Mice
  • Molecular Sequence Data
  • Sequence Analysis, RNA
  • T-Box Domain Proteins / genetics*
  • Transcription Factors / genetics*
  • Wings, Animal / embryology*

Substances

  • Eye Proteins
  • T-Box Domain Proteins
  • Transcription Factors

Associated data

  • GENBANK/KJ670370
  • GENBANK/KJ670371

Grants and funding

This work was funded by grants from the National Natural Science Foundation of China (No. 31301191, 31172077, 91120001), the State Education Ministry of China (SRF for ROCS), Science and Technology Commission of Shanghai Municipality (No. 13ZR1412700) and East China Normal University. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.