Pena R N, Folch J M, Sánchez A, Whitelaw C B
Unitat de Genètica i Millora, Departament de Patologia i Producció Animals, Facultat de Veterinària, Universitat Autònoma de Barcelona, Bellaterra, 08193, Spain.
Biochem Biophys Res Commun. 1998 Nov 27;252(3):649-53. doi: 10.1006/bbrc.1998.9718.
Different levels of the major milk protein beta-lactoglobulin are found in evolutionarily related ruminant species: with sheep milk containing as much as three times the concentration in goat milk. In an attempt to understand why these differences exist, we have characterised, using DNaseI as a probe of structure, the chromatin surrounding the goat beta-lactoglobulin promoter and compared it to that of the sheep homologue. The goat gene displays a mammary-specific chromatin pattern, which is reformed on expressing goat beta-lactoglobulin transgenes. This implies that this chromatin structure is sequence dependent and suggests that it plays a role in regulating beta-lactoglobulin gene expression. This pattern differs from that seen on the ovine beta-lactoglobulin gene in lactating sheep mammary chromatin. Thus, even between highly related species, the transcriptional mechanisms regulating activity of a gene can differ.
在进化上相关的反刍动物物种中发现了不同水平的主要乳蛋白β-乳球蛋白：羊奶中的含量高达山羊奶的三倍。为了理解这些差异存在的原因，我们使用脱氧核糖核酸酶I作为结构探针，对山羊β-乳球蛋白启动子周围的染色质进行了表征，并将其与绵羊同源物的染色质进行了比较。山羊基因呈现出乳腺特异性染色质模式，在表达山羊β-乳球蛋白转基因时会重新形成。这意味着这种染色质结构是序列依赖性的，并表明它在调节β-乳球蛋白基因表达中起作用。这种模式与泌乳绵羊乳腺染色质中绵羊β-乳球蛋白基因的模式不同。因此，即使在高度相关的物种之间，调节基因活性的转录机制也可能不同。
