TGFβ signaling is required for sclerotome resegmentation during development of the spinal column in Gallus gallus

Building a vertebra: Development of the amniote sclerotome

“…Vice versa, this implies that a single vertebra arises from two adjacent somite halves by a combination of the respective cranial and caudal sclerotomal subdomains (Aoyama & Asamoto, 2000;Bagnall et al, 1988Bagnall et al, , 1989. Later studies by viral and vital dye labeling confirmed these data (Evans, 2003;Ward et al, 2017), and chemical inhibitor experiments showed that resegmentation depends on transforming growth factor β (TGFβ)-signaling (Clayton et al, 2022). Resegmentation occurs in the vertebral bodies, in part of the vertebral arch as well as in the distal ribs.…”

“…The developing Anulus fibrosus , with its characteristic cross‐ply arrangement of tense fibers, is characterized by expression of collagens including collagen type I as well as heparan sulfate proteoglycans (HSPGs) including syndecan‐4 and glypican‐6, and is controlled by TGFβ1 signaling via TGFβR2 (Beckett et al, 2015; Hayes, Hughes, et al, 2011; Hayes, Isaacs, et al, 2011; Sohn et al, 2010). According to a recent model, TGFß signaling induces expression of scleraxis via ERK1/2, thus promoting expression of the proteoglycan fibromodulin and other proteins involved in the assembly of collagen fibers (Clayton et al, 2022). On the other hand, TGFβ inhibits chondrogenesis‐inducing BMP signaling probably by promoting the BMP‐inhibitor noggin (Ban et al, 2019).…”