Hbb-y, a gene encoding a beta-like embryonic chain of hemoglobin, is crucial in embryonic globin expression. Hemoglobin, with its globin chains, is essential for oxygen transport in the body, and thus Hbb-y plays a vital role in the normal physiological function during embryonic development. Mouse models are valuable genetic tools for studying Hbb-y [1,2,3,4].

In Gfi1b-deficient mice, which serve as a model for studying erythroid cell maturation and globin gene regulation, the Hbb-y gene was upregulated in TER119+ fetal liver cells during gestation (day 12.5-17.5 p.c.), and this increased expression was maintained in adult Gfi1b-deficient mice. This indicates that Gfi1b is a regulator of Hbb-y expression and suggests Hbb-y's role in erythroid maturation [4]. Additionally, exposure to certain androgen receptor antagonists like flutamide, linuron, and p,p'-DDE in rat fetal testes led to a reduction in Hbb-y expression, though the exact implications of this on testicular development are yet to be fully understood [5].

In conclusion, Hbb-y is important for embryonic globin expression and may be involved in erythroid cell maturation. The use of gene-modified mouse models, such as Gfi1b-deficient mice, has provided insights into Hbb-y's role in these biological processes. While its role in the context of androgen receptor antagonist-induced changes in the fetal testis is less clear, further research may clarify its significance in this and other disease-related scenarios.

References:

1. Brown, B A, Padgett, R W, Hardies, S C, Hutchison, C A, Edgell, M H. . beta-globin transcript found in induced murine erythroleukemia cells is homologous to the beta h0 and beta h1 genes. In Proceedings of the National Academy of Sciences of the United States of America, 79, 2753-7. doi:. https://pubmed.ncbi.nlm.nih.gov/6953428/

2. Padgett, R W, Loeb, D D, Snyder, L R, Edgell, M H, Hutchison, C A. . The molecular organization of the beta-globin complex of the deer mouse, Peromyscus maniculatus. In Molecular biology and evolution, 4, 30-45. doi:. https://pubmed.ncbi.nlm.nih.gov/3447002/

3. May, Andreas, Reifenberg, Kurt, Zechner, Ulrich, Haaf, Thomas. 2008. Asynchronous replication dynamics of imprinted and non-imprinted chromosome regions in early mouse embryos. In Experimental cell research, 314, 2788-95. doi:10.1016/j.yexcr.2008.07.009. https://pubmed.ncbi.nlm.nih.gov/18675801/

4. Vassen, Lothar, Beauchemin, Hugues, Lemsaddek, Wafaa, Trudel, Marie, Möröy, Tarik. 2014. Growth factor independence 1b (gfi1b) is important for the maturation of erythroid cells and the regulation of embryonic globin expression. In PloS one, 9, e96636. doi:10.1371/journal.pone.0096636. https://pubmed.ncbi.nlm.nih.gov/24800817/

5. Mu, Xueyan, Liu, Kejun, Kleymenova, Elena, Young, S Stanley, Gaido, Kevin W. . Gene expression profiling of androgen receptor antagonists in the rat fetal testis reveals few common gene targets. In Journal of biochemical and molecular toxicology, 20, 7-17. doi:. https://pubmed.ncbi.nlm.nih.gov/16498641/