Question

You know that Gip1 is only expressed in adult liver cells and not in the liver of embryos. You also know that JK8 and Pa5 behave similarly on other promoters in the embryo or in the adult, in terms of whether they act as repressors or gene activators. Give the data, use of which of the following mechanisms would make the most sense for regulation the Jk8 and Pa5 proteins:

(a) Jk8 is ubiquitylated and targeted for destruction in adult cells
(b) Jk8, but not Pa5, is transcribed in embryo liver cells
(c) Jk8 binds to the promoter of the gene that encodes Jk8 in embryo liver cells
(d) Pa5 binds to the promoter of the gene that encodes Jk8 in embryonic liver cells

Answer 1

Understanding the regulation of proteins JK8 and Pa5 in the expression of the liver-specific gene Gip1 involves analyzing their roles as transcription factors and how changes in their ubiquitylation or transcription pattern might affect gene expression.

Step-by-step explanation:

The student's question centers around the mechanisms by which the proteins JK8 and Pa5 are regulated in the context of gene expression specific to liver cells during different development stages. Given that the liver-specific gene Gip1 is only expressed in adult liver cells and not embryonic ones, and that JK8 and Pa5 typically function consistently as either repressors or activators across different promoters, the question posits several hypothetical regulatory mechanisms for these proteins. Understanding the behaviors of transcription factors and regulatory proteins is crucial for elucidating the gene regulation mechanisms. In this case, comparing the specific roles of JK8 and Pa5 in both adult and embryonic liver cells, as well as understanding how protein modification, like ubiquitylation (degradation) or transcriptional control (expression patterns), could clarify how Gip1 expression is regulated.