β‐Microseminoprotein‐related molecules may participate in formation of the mesoderm in the chick embryo

Abstract

It has previously been shown that human ␤ -microseminoprotein enhances development of mesodermal structures in the chick embryo. The present study was carried out to elucidate the mechanism of action of human ␤ -microseminoprotein in the chick embryo. ␤ -Microseminoprotein brought about significant modulation of expression of Brachyury in gastrulating embryos. In approximately 50% of the treated embryos, Brachyury expression was enhanced around the Hensen's node. These cells not only expressed higher levels of Brachyury , but also appeared to switch off Brachyury expression prematurely, postinvagination. The spatial modulation of Brachyury is not clearly reflected in the northern blots, indicating that ␤ -microseminoprotein treatment results in redistribution of available transcripts or that the upregulation is compensated for by early switching off of Brachyury postinvagination. Because higher levels of Brachyury during gastrulation are believed to result in early exit of cells from the primitive streak, ␤ -microseminoprotein treatment appeared to have stimulated morphogenetic movements by upregulating Brachyury around the Hensen's node. This deduction was confirmed by scanning electron microscopic analysis that showed that altered morphogenetic movements accompany modulation of Brachyury . The specific responses elicited by ␤ -microseminoprotein indicate presence of a structurally related molecule in the chick. By western blotting, similar molecules were indeed detected in the chicken seminal plasma and in chick embryos. These data strongly suggest that ␤ -microseminoprotein-related molecule(s) participates in mesoderm formation in the chick embryo.

The sea cucumber genome provides insights into morphological evolution and visceral regeneration

“…Further analysis on the translated amino acid sequences of these genes showed that they all had a domain that was analogous to the prostatic secretory protein of 94 amino acids (PSP94) based on the topological similarities of the cysteine residues, so we designated them as PSP94-like genes (Fig 6C). It was reported that the PSP94 genes in vertebrates underwent rapid evolution, which resulted in an improvement of their functions in a wide range of biological activities, such as inhibition of tumor growth [46], activation of immunity [47], and mesoderm formation [48]. Taken together, their specific arrangement pattern and distinguished expression profiles strongly suggested that the PSP94-like genes might play a vital role in the regenerative abilities of A .…”

Acceleration of early chick embryo morphogenesis by insulin is associated with altered expression of embryonic genes

“…Since Brachyury is required for convergent extension during gastrulation, cell survival and mesoderm formation (Conlon and Smith, 1999), these growth-promoting processes could be enhanced when extra Brachyury is available. Interestingly, chick embryos treated with exogenous FGF at HH stage 4 show a significant reduction in the length of body axis and corresponding downregulation of Brachyury expression (Khot and Ghaskadbi, 2001) while ß-microseminoprotein has an exactly opposite effect (Karandikar and Ghaskadbi, 2003) indicating a direct correlation between the two. The response of frog Brachyury to insulin is different however, it is found to be down regulated (Chatterjee and Ghaskadbi, 2002).…”

“…This duration of treatment is sufficient to detect changes, if any, at the transcriptional level (Khot and Ghaskadbi, 2001;Karandikar and Ghaskadbi, 2003). The embryos were fixed in 4% paraformaldehyde at 4ºC overnight.…”

“…Recent studies from our laboratory show that several molecules performing important functions in the adult life of an organism also participate in crucial phenomena in early development (Khot and Ghaskadbi, 2001;Patwardhan and Ghaskadbi, 2001;Karandikar and Ghaskadbi, 2003). Insulin and related ligands is one group of molecules important in early embryonic development especially of the nervous system Ghaskadbi andGhate, 1993, 1995;De Pablo and De La Rosa, 1995).…”

The heart forming region of early chick embryo is an alternative source of embryonic stem cells

“…HH stage 4 embryos were cultured in vitro using single ring technique (New, 1955) with modifications as described before (Khot and Ghaskadbi, 2001;Karandikar and Ghaskadbi, 2003;Patwardhan et al, 2004). To study the fate of cells derived from HFRs, the cells were grafted on the cultured embryos.…”