Sedkov Y, Benes J J, Berger J R, Riker K M, Tillib S, Jones R S, Mazo A
Department of Microbiology and Immunology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA.
Mech Dev. 1999 Apr;82(1-2):171-9. doi: 10.1016/s0925-4773(98)00246-9.
The products of the trithorax and Polycomb groups genes maintain the activity and silence, respectively, of many developmental genes including genes of the homeotic complexes. This transcriptional regulation is likely to involve modification of chromatin structure. Here, we report the cloning and characterization of a new gene, trithorax-related (trr), which shares sequence similarities with members of both the trithorax and Polycomb groups. The trr transcript is 9.6 kb in length and is present throughout development. The TRR protein, as predicted from the nucleotide sequence of the open reading frame, is 2431 amino acids in length and contains a PHD finger-like domain and a SET domain, two highly conserved protein motifs found in several trithorax and Polycomb group proteins, and in modifiers of position effect variegation. TRR is most similar in sequence to the human ALR protein, suggesting that trr is a Drosophila homologue of the ALR. TRR is also highly homologous to Drosophila TRITHORAX protein and to its human homologue, ALL-1/HRX. However, preliminary genetic analysis of a trr null allele suggests that TRR protein may not be involved in regulation of homeotic genes (i.e. not a member of the trithorax or Polycomb groups) or in position effect variegation.
三胸节和多梳蛋白家族基因的产物分别维持许多发育基因的活性和沉默状态，这些发育基因包括同源异型复合体的基因。这种转录调控可能涉及染色质结构的修饰。在此，我们报告了一个新基因——三胸节相关基因（trr）的克隆与特性分析，该基因与三胸节和多梳蛋白家族的成员均具有序列相似性。trr转录本长度为9.6 kb，在整个发育过程中均有表达。根据开放阅读框的核苷酸序列预测，TRR蛋白长度为2431个氨基酸，包含一个类PHD指结构域和一个SET结构域，这是在几种三胸节和多梳蛋白家族蛋白以及位置效应斑驳修饰因子中发现的两个高度保守的蛋白基序。TRR在序列上与人类ALR蛋白最为相似，这表明trr是ALR的果蝇同源物。TRR也与果蝇三胸节蛋白及其人类同源物ALL-1/HRX高度同源。然而，对trr无效等位基因的初步遗传分析表明，TRR蛋白可能不参与同源异型基因的调控（即不是三胸节或多梳蛋白家族的成员），也不参与位置效应斑驳。
