Theurkauf W E, Baum H, Bo J, Wensink P C
Proc Natl Acad Sci U S A. 1986 Nov;83(22):8477-81. doi: 10.1073/pnas.83.22.8477.
We have determined the nucleotide sequences of all four Drosophila alpha-tubulin genes (alpha 1, alpha 2, alpha 3, and alpha 4). Two of the genes, alpha 1 and alpha 3, are constitutively expressed and code for proteins that are very similar to previously sequenced alpha-tubulins. They differ from each other by only two amino acid substitutions. These two genes also have blocks of homology between the noncoding leader regions of their transcription units. In contrast to these constitutive genes, the tissue-specific alpha 2 and alpha 4 genes code for tubulins with different structures. The alpha 2 mRNA is male-specific in adults and codes for a tubulin that differs from alpha 1 at 21 of the 450 residues. Six nonconservative substitutions are clustered within the 14 carboxyl-terminal amino acids, a region implicated in the regulation of microtubule assembly. The alpha 4 mRNA is maternal and is found only in ovarian nurse cells, eggs, and early embryos. It codes for the most highly divergent alpha-tubulin yet reported and differs from alpha 1 at 149 positions.
我们已经确定了果蝇的全部四个α-微管蛋白基因（α1、α2、α3和α4）的核苷酸序列。其中两个基因，α1和α3，组成性表达，编码的蛋白质与先前测序的α-微管蛋白非常相似。它们彼此之间仅相差两个氨基酸替换。这两个基因在其转录单元的非编码前导区之间也有同源性区段。与这些组成性基因不同，组织特异性的α2和α4基因编码具有不同结构的微管蛋白。α2 mRNA在成虫中是雄性特异性的，编码一种微管蛋白，该微管蛋白在450个残基中的21个位置上与α1不同。六个非保守替换聚集在14个羧基末端氨基酸内，该区域与微管组装的调节有关。α4 mRNA是母源性的，仅存在于卵巢滋养细胞、卵和早期胚胎中。它编码迄今报道的差异最大的α-微管蛋白，与α1在多达149个位置上不同。
