Premium
Disparate I gf1 Expression and Growth in the Fore‐ and Hind Limbs of a Marsupial Mammal ( M onodelphis domestica )
Author(s) -
SEARS KAREN E.,
PATEL ANKIT,
HÜBLER MERLA,
CAO XIAOYI,
VANDEBERG JOHN L.,
ZHONG SHENG
Publication year - 2012
Publication title -
journal of experimental zoology part b: molecular and developmental evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.823
H-Index - 63
eISSN - 1552-5015
pISSN - 1552-5007
DOI - 10.1002/jez.b.22444
Subject(s) - opossum , monodelphis domestica , marsupial , biology , didelphis , anatomy , microbiology and biotechnology , zoology
Proper regulation of growth is essential to all stages of life, from development of the egg into an embryo to the maintenance of normal cell cycle progression in adults. However, despite growth's importance to basic biology and health, little is known about how mammalian growth is regulated. In this study, we investigated the molecular basis of the highly disparate growth of opossum fore‐ and hind limbs in utero. We first used a novel, opossum‐specific microarray to identify several growth‐related genes that are differentially expressed in opossum fore‐ and hind limbs of comparable developmental stages. These genes included I gf1 . Given I gf1 's role in the growth of other systems, we further investigated the role of I gf1 in opossum limb growth. Supporting the microarray results, RT ‐ PCR indicated that I gf1 levels are approximately two times higher in opossum fore‐ than hind limbs. Consistent with this, while I gf1 transcripts were readily detectable in opossum forelimbs using whole‐mount in situ hybridization, they were not detectable in opossum hind limbs. Furthermore, opossum limbs treated with exogenous I gf1 protein experienced significantly greater cellular proliferation and growth than control limbs in vitro. Taken together, results suggest that the differential expression of I gf1 in developing opossum limbs contributes to their divergent rate of growth, and the unique limb phenotype of opossum newborns. This study establishes the opossum limb as a new mammalian model system for study of organ growth. J. Exp. Zool. (Mol. Dev. Evol.) 318:279–293, 2012 . © 2012 Wiley Periodicals, Inc.