McPhaul M J, Matsumine H, Herbst M A, Wilson J D
Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas 75235-8857.
Trans Assoc Am Physicians. 1991;104:141-9.
These studies have clarified a number of issues regarding the genetic control of extragonadal aromatase expression in birds carrying the henny-feathering trait. The marked increased in extragonadal aromatase expression of a unique species of aromatase mRNA is apparently controlled by a retrovirus. We have not yet established whether this promoter is the consequence of a new retroviral insertion or is due to a mutation in a preexisting retrovirus. It is of interest in this regard that the chicken aromatase gene is located in a region of chromosome 1 known to be rich in retroviral insertions. Second, the relationship of the henny-feathering trait to normal and abnormal extragonadal aromatase expression in man remains to be determined. At one extreme, it is possible that a similar mechanism may underlie syndromes typified by increases in extraglandular aromatase expression. Even if the parallel proves to be less exact, the Sebright chicken provides important insight into how aromatase expression may be modulated differently in different tissues. Finally, the discovery that retroviral sequences appear to modulate the expression of aromatase in extragonadal tissues represents an unusual method by which the genetic control of genes can be altered. In the case of the henny-feathering trait, the alteration in the dimorphic feathering pattern was the principal clue to the altered regulation of extragonadal aromatase. This relation is in keeping with the other examples of altered gene expression caused by retroviruses that have also caused morphologic alterations such as changes in coat color or the appearance of neoplasms (for examples, see Refs. 14-16).(ABSTRACT TRUNCATED AT 250 WORDS)
这些研究阐明了一些关于携带母鸡羽型性状的鸟类性腺外芳香化酶表达的遗传控制问题。一种独特的芳香化酶mRNA的性腺外芳香化酶表达显著增加显然受一种逆转录病毒控制。我们尚未确定该启动子是新的逆转录病毒插入的结果还是由于先前存在的逆转录病毒发生突变所致。在这方面有趣的是，鸡芳香化酶基因位于已知富含逆转录病毒插入序列的1号染色体区域。其次，母鸡羽型性状与人类正常和异常性腺外芳香化酶表达之间的关系仍有待确定。在一种极端情况下，可能类似的机制是以外腺芳香化酶表达增加为典型特征的综合征的基础。即使这种平行关系被证明不太确切，塞布赖特鸡也为不同组织中芳香化酶表达如何被不同调节提供了重要见解。最后，逆转录病毒序列似乎调节性腺外组织中芳香化酶表达这一发现代表了一种改变基因遗传控制的不同寻常方法。就母鸡羽型性状而言，双态羽型模式的改变是性腺外芳香化酶调节改变的主要线索。这种关系与逆转录病毒引起的基因表达改变的其他例子一致，这些例子也导致了形态学改变，如毛色变化或肿瘤出现（例如，见参考文献14 - 16）。（摘要截短至250字）
