1
|
Brent AE, Buchholtz EA, Mansfield JH. Evolutionary assembly and disassembly of the mammalian sternum. Curr Biol 2023; 33:197-205.e2. [PMID: 36563692 DOI: 10.1016/j.cub.2022.11.055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 10/15/2022] [Accepted: 11/23/2022] [Indexed: 12/24/2022]
Abstract
Evolutionary transitions are frequently associated with novel anatomical structures,1 but the origins of the structures themselves are often poorly known. We use developmental, genetic, and paleontological data to demonstrate that the therian sternum was assembled from pre-existing elements. Imaging of the perinatal mouse reveals two paired sternal elements, both composed primarily of cells with lateral plate mesoderm origin. Location, articulations, and development identify them as homologs of the interclavicle and the sternal bands of synapsid outgroups. The interclavicle, not previously recognized in therians,2 articulates with the clavicle and differs from the sternal bands in both embryonic HOX expression and pattern of skeletal maturation. The sternal bands articulate with the ribs in two styles, most clearly differentiated by their association with sternebrae. Evolutionary trait mapping indicates that the interclavicle and sternal bands were independent elements throughout most of synapsid history. The differentiation of rib articulation styles and the subdivision of the sternal bands into sternebrae were key innovations likely associated with transitions in locomotor and respiratory mechanics.3,4 Fusion of the interclavicle and the anterior sternal bands to form a presternum anterior to the first sternebra was a historically recent innovation unique to therians. Subsequent disassembly of the radically reduced sternum of mysticete cetaceans was element specific, reflecting the constraints that conserved developmental programs exert on composite structures.
Collapse
Affiliation(s)
- Ava E Brent
- Department of Biology, Barnard College, Columbia University, 3009 Broadway, New York, NY 10027, USA
| | - Emily A Buchholtz
- Department of Biological Sciences, Wellesley College, 106 Central Street, Wellesley, MA 02481, USA.
| | - Jennifer H Mansfield
- Department of Biology, Barnard College, Columbia University, 3009 Broadway, New York, NY 10027, USA
| |
Collapse
|
2
|
Chang YC, Manent J, Schroeder J, Wong SFL, Hauswirth GM, Shylo NA, Moore EL, Achilleos A, Garside V, Polo JM, Trainor P, McGlinn E. Nr6a1 controls Hox expression dynamics and is a master regulator of vertebrate trunk development. Nat Commun 2022; 13:7766. [PMID: 36522318 PMCID: PMC9755267 DOI: 10.1038/s41467-022-35303-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 11/28/2022] [Indexed: 12/23/2022] Open
Abstract
The vertebrate main-body axis is laid down during embryonic stages in an anterior-to-posterior (head-to-tail) direction, driven and supplied by posteriorly located progenitors. Whilst posterior expansion and segmentation appears broadly uniform along the axis, there is developmental and evolutionary support for at least two discrete modules controlling processes within different axial regions: a trunk and a tail module. Here, we identify Nuclear receptor subfamily 6 group A member 1 (Nr6a1) as a master regulator of trunk development in the mouse. Specifically, Nr6a1 was found to control vertebral number and segmentation of the trunk region, autonomously from other axial regions. Moreover, Nr6a1 was essential for the timely progression of Hox signatures, and neural versus mesodermal cell fate choice, within axial progenitors. Collectively, Nr6a1 has an axially-restricted role in all major cellular and tissue-level events required for vertebral column formation, supporting the view that changes in Nr6a1 levels may underlie evolutionary changes in axial formulae.
Collapse
Affiliation(s)
- Yi-Cheng Chang
- grid.1002.30000 0004 1936 7857EMBL Australia, Monash University, Clayton, Victoria 3800 Australia ,grid.1002.30000 0004 1936 7857Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800 Australia
| | - Jan Manent
- grid.1002.30000 0004 1936 7857EMBL Australia, Monash University, Clayton, Victoria 3800 Australia ,grid.1002.30000 0004 1936 7857Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800 Australia
| | - Jan Schroeder
- grid.1002.30000 0004 1936 7857Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800 Australia ,grid.1002.30000 0004 1936 7857Department of Anatomy and Developmental Biology, Monash University, Clayton, VIC Australia ,grid.1002.30000 0004 1936 7857Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Clayton, VIC Australia
| | - Siew Fen Lisa Wong
- grid.1002.30000 0004 1936 7857EMBL Australia, Monash University, Clayton, Victoria 3800 Australia ,grid.1002.30000 0004 1936 7857Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800 Australia
| | - Gabriel M. Hauswirth
- grid.1002.30000 0004 1936 7857EMBL Australia, Monash University, Clayton, Victoria 3800 Australia ,grid.1002.30000 0004 1936 7857Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800 Australia
| | - Natalia A. Shylo
- grid.250820.d0000 0000 9420 1591Stowers Institute for Medical Research, Kansas City, Missouri USA
| | - Emma L. Moore
- grid.250820.d0000 0000 9420 1591Stowers Institute for Medical Research, Kansas City, Missouri USA
| | - Annita Achilleos
- grid.250820.d0000 0000 9420 1591Stowers Institute for Medical Research, Kansas City, Missouri USA ,grid.413056.50000 0004 0383 4764University of Nicosia, Nicosia, Cyprus
| | - Victoria Garside
- grid.1002.30000 0004 1936 7857EMBL Australia, Monash University, Clayton, Victoria 3800 Australia ,grid.1002.30000 0004 1936 7857Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800 Australia
| | - Jose M. Polo
- grid.1002.30000 0004 1936 7857Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800 Australia ,grid.1002.30000 0004 1936 7857Department of Anatomy and Developmental Biology, Monash University, Clayton, VIC Australia ,grid.1002.30000 0004 1936 7857Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Clayton, VIC Australia
| | - Paul Trainor
- grid.250820.d0000 0000 9420 1591Stowers Institute for Medical Research, Kansas City, Missouri USA ,grid.412016.00000 0001 2177 6375Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, Kansas USA
| | - Edwina McGlinn
- grid.1002.30000 0004 1936 7857EMBL Australia, Monash University, Clayton, Victoria 3800 Australia ,grid.1002.30000 0004 1936 7857Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800 Australia
| |
Collapse
|
3
|
Mitchel K, Bergmann JM, Brent AE, Finkelstein TM, Schindler KA, Holzman MA, Jeannotte L, Mansfield JH. Hoxa5 Activity Across the Lateral Somitic Frontier Regulates Development of the Mouse Sternum. Front Cell Dev Biol 2022; 10:806545. [PMID: 35557949 PMCID: PMC9086245 DOI: 10.3389/fcell.2022.806545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 03/03/2022] [Indexed: 11/13/2022] Open
Abstract
The skeletal system derives from multiple embryonic sources whose derivatives must develop in coordination to produce an integrated whole. In particular, interactions across the lateral somitic frontier, where derivatives of the somites and lateral plate mesoderm come into contact, are important for proper development. Many questions remain about genetic control of this coordination, and embryological information is incomplete for some structures that incorporate the frontier, including the sternum. Hox genes act in both tissues as regulators of skeletal pattern. Here, we used conditional deletion to characterize the tissue-specific contributions of Hoxa5 to skeletal patterning. We found that most aspects of the Hoxa5 skeletal phenotype are attributable to its activity in one or the other tissue, indicating largely additive roles. However, multiple roles are identified at the junction of the T1 ribs and the anterior portion of the sternum, or presternum. The embryology of the presternum has not been well described in mouse. We present a model for presternum development, and show that it arises from multiple, paired LPM-derived primordia. We show evidence that HOXA5 expression marks the embryonic precursor of a recently identified lateral presternum structure that is variably present in therians.
Collapse
Affiliation(s)
- Kira Mitchel
- Department of Biology, Barnard College, Columbia University, New York, NY, United States
| | - Jenna M. Bergmann
- Department of Biology, Barnard College, Columbia University, New York, NY, United States
| | - Ava E. Brent
- Department of Biology, Barnard College, Columbia University, New York, NY, United States
- *Correspondence: Ava E. Brent, ; Jennifer H. Mansfield,
| | - Tova M. Finkelstein
- Department of Biology, Barnard College, Columbia University, New York, NY, United States
| | - Kyra A. Schindler
- Department of Biology, Barnard College, Columbia University, New York, NY, United States
| | - Miriam A. Holzman
- Department of Biology, Barnard College, Columbia University, New York, NY, United States
| | - Lucie Jeannotte
- Department of Molecular Biology, Medical Biochemistry and Pathology, Faculty of Medicine, Université Laval, Québec, QC, Canada
- Centre de Recherche sur le Cancer de l'Université Laval, CRCHU de Québec‐Université, Laval (Oncology Axis), Québec, QC, Canada
| | - Jennifer H. Mansfield
- Department of Biology, Barnard College, Columbia University, New York, NY, United States
- *Correspondence: Ava E. Brent, ; Jennifer H. Mansfield,
| |
Collapse
|
4
|
Abstract
The vertebral column of individual mammalian species often exhibits remarkable robustness in the number and identity of vertebral elements that form (known as axial formulae). The genetic mechanism(s) underlying this constraint however remain ill-defined. Here, we reveal the interplay of three regulatory pathways (Gdf11, miR-196 and Retinoic acid) is essential in constraining total vertebral number and regional axial identity in the mouse, from cervical through to tail vertebrae. All three pathways have differing control over Hox cluster expression, with heterochronic and quantitative changes found to parallel changes in axial identity. However, our work reveals an additional role for Hox genes in supporting axial elongation within the tail region, providing important support for an emerging view that mammalian Hox function is not limited to imparting positional identity as the mammalian body plan is laid down. More broadly, this work provides a molecular framework to interrogate mechanisms of evolutionary change and congenital anomalies of the vertebral column. Vertebral column length and shape exhibits remarkable robustness within a species but diversity across species. Here the authors reveal the molecular logic constraining vertebral number in mouse and a novel role for posterior Hox genes in this context.
Collapse
|
5
|
Holzman MA, Ryckman A, Finkelstein TM, Landry-Truchon K, Schindler KA, Bergmann JM, Jeannotte L, Mansfield JH. HOXA5 Participates in Brown Adipose Tissue and Epaxial Skeletal Muscle Patterning and in Brown Adipocyte Differentiation. Front Cell Dev Biol 2021; 9:632303. [PMID: 33732701 PMCID: PMC7959767 DOI: 10.3389/fcell.2021.632303] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 02/02/2021] [Indexed: 11/13/2022] Open
Abstract
Brown adipose tissue (BAT) plays critical thermogenic, metabolic and endocrine roles in mammals, and aberrant BAT function is associated with metabolic disorders including obesity and diabetes. The major BAT depots are clustered at the neck and forelimb levels, and arise largely within the dermomyotome of somites, from a common progenitor with skeletal muscle. However, many aspects of BAT embryonic development are not well understood. Hoxa5 patterns other tissues at the cervical and brachial levels, including skeletal, neural and respiratory structures. Here, we show that Hoxa5 also positively regulates BAT development, while negatively regulating formation of epaxial skeletal muscle. HOXA5 protein is expressed in embryonic preadipocytes and adipocytes as early as embryonic day 12.5. Hoxa5 null mutant embryos and rare, surviving adults show subtly reduced iBAT and sBAT formation, as well as aberrant marker expression, lower adipocyte density and altered lipid droplet morphology. Conversely, the epaxial muscles that arise from a common dermomyotome progenitor are expanded in Hoxa5 mutants. Conditional deletion of Hoxa5 with Myf5/Cre can reproduce both BAT and epaxial muscle phenotypes, indicating that HOXA5 is necessary within Myf5-positive cells for proper BAT and epaxial muscle development. However, recombinase-based lineage tracing shows that Hoxa5 does not act cell-autonomously to repress skeletal muscle fate. Interestingly, Hoxa5-dependent regulation of adipose-associated transcripts is conserved in lung and diaphragm, suggesting a shared molecular role for Hoxa5 in multiple tissues. Together, these findings establish a role for Hoxa5 in embryonic BAT development.
Collapse
Affiliation(s)
- Miriam A. Holzman
- Department of Biology, Barnard College, Columbia University, New York, NY, United States
| | - Abigail Ryckman
- Department of Biology, Barnard College, Columbia University, New York, NY, United States
| | - Tova M. Finkelstein
- Department of Biology, Barnard College, Columbia University, New York, NY, United States
| | - Kim Landry-Truchon
- Centre de Recherche sur le Cancer de l’Université Laval, CRCHU de Québec-Université Laval (Oncology), Québec City, QC, Canada
| | - Kyra A. Schindler
- Department of Biology, Barnard College, Columbia University, New York, NY, United States
| | - Jenna M. Bergmann
- Department of Biology, Barnard College, Columbia University, New York, NY, United States
| | - Lucie Jeannotte
- Centre de Recherche sur le Cancer de l’Université Laval, CRCHU de Québec-Université Laval (Oncology), Québec City, QC, Canada
| | - Jennifer H. Mansfield
- Department of Biology, Barnard College, Columbia University, New York, NY, United States
| |
Collapse
|
6
|
Coughlan E, Garside VC, Wong SFL, Liang H, Kraus D, Karmakar K, Maheshwari U, Rijli FM, Bourne J, McGlinn E. A Hox Code Defines Spinocerebellar Neuron Subtype Regionalization. Cell Rep 2019; 29:2408-2421.e4. [DOI: 10.1016/j.celrep.2019.10.048] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 08/12/2019] [Accepted: 10/10/2019] [Indexed: 11/25/2022] Open
|
7
|
Young JJ, Grayson P, Edwards SV, Tabin CJ. Attenuated Fgf Signaling Underlies the Forelimb Heterochrony in the Emu Dromaius novaehollandiae. Curr Biol 2019; 29:3681-3691.e5. [PMID: 31668620 DOI: 10.1016/j.cub.2019.09.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 08/21/2019] [Accepted: 09/06/2019] [Indexed: 11/19/2022]
Abstract
Powered flight was fundamental to the establishment and radiation of birds. However, flight has been lost multiple times throughout avian evolution. Convergent losses of flight within the ratites (flightless paleognaths, including the emu and ostrich) often coincide with reduced wings. Although there is a wealth of anatomical knowledge for several ratites, the genetic mechanisms causing these changes remain debated. Here, we use a multidisciplinary approach employing embryological, genetic, and genomic techniques to interrogate the mechanisms underlying forelimb heterochrony in emu embryos. We show that the initiation of limb formation, an epithelial to mesenchymal transition (EMT) in the lateral plate mesoderm (LPM) and myoblast migration into the LPM, occur at equivalent stages in the emu and chick. However, the emu forelimb fails to subsequently proliferate. The unique emu forelimb expression of Nkx2.5, previously associated with diminished wing development, initiates after this stage (concomitant with myoblast migration into the LPM) and is therefore unlikely to cause this developmental delay. In contrast, RNA sequencing of limb tissue reveals significantly lower Fgf10 expression in the emu forelimb. Artificially increasing Fgf10 expression in the emu LPM induces ectodermal Fgf8 expression and a limb bud. Analyzing open chromatin reveals differentially active regulatory elements near Fgf10 and Sall-1 in the emu wing, and the Sall-1 enhancer activity is dependent on a likely Fgf-mediated Ets transcription factor-binding site. Taken together, our results suggest that regulatory changes result in lower expression of Fgf10 and a concomitant failure to express genes required for limb proliferation in the early emu wing bud.
Collapse
Affiliation(s)
- John J Young
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Phil Grayson
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
| | - Scott V Edwards
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
| | - Clifford J Tabin
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA.
| |
Collapse
|