Sequence of a complete chicken BG haplotype shows dynamic expansion and contraction of two gene lineages with particular expression patterns.
Sequence of a complete chicken BG haplotype shows dynamic expansion and contraction of two gene lineages with particular expression patterns.
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DOI：
10.1371/journal.pgen.1004417
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发表时间：
2014-06
期刊：
影响因子：
4.5
通讯作者：
Kaufman J
中科院分区：
文献类型：
--
作者：
Salomonsen J;Chattaway JA;Chan AC;Parker A;Huguet S;Marston DA;Rogers SL;Wu Z;Smith AL;Staines K;Butter C;Riegert P;Vainio O;Nielsen L;Kaspers B;Griffin DK;Yang F;Zoorob R;Guillemot F;Auffray C;Beck S;Skjødt K;Kaufman J
许多在免疫中重要的基因被发现为多基因家族。亲丁酸蛋白基因是B7家族的成员，在共调节和可能在抗原呈递中发挥不同的作用。在人类中，在主要组织相容性复合体（MHC）中及其周围发现了固定数量的亲丁酸蛋白基因，并显示出与特定自身免疫性疾病的显著关联。在鸡中，BG基因编码具有稍微不同的结构域组织的同源物。只有少数BG基因已被鉴定，一个涉及肌动蛋白-肌球蛋白相互作用在肠道刷状缘，另一个涉及抵抗病毒性疾病。我们对B12鸡的所有BG基因进行了测序，发现一个多基因家族在MHC外的BG区域中以串联重复序列的形式组织，在MHC（BF-BL区域）中有一个单基因，在不同的染色体上有另一个单基因。每个基因都有精确的细胞和组织表达，但总体上有两种，由造血细胞表达的基因和在组织中表达的基因（推测为非造血细胞），与两种不同类型的启动子和5′非翻译区（5′UTR）相关。然而，在BG区域的多基因家族包含许多杂交基因，这表明重组和/或删除作为主要的进化力量。我们确定BG基因在鸡全基因组鸟枪序列，以及通过比较其他单倍型纤维荧光原位杂交，确认动态扩张和收缩内的BG区域。因此，鸡中的BG基因与其在哺乳动物中的同源物相比正在经历更快的进化，原因尚不清楚。许多免疫基因是多基因家族，可能是为了响应病原体的变异。一些多基因家族经历扩张和收缩，导致拷贝数变异（CNV），可能是由于更强烈的选择。最近，由于与自身免疫性疾病的遗传关联以及在免疫共调节和抗原呈递中的作用，人类和其他哺乳动物中的亲丁酸蛋白家族受到了仔细审查。Butyrophilin基因表现出等位基因多态性，但基因数量在一个物种内似乎稳定。我们发现鸡的BG同源物差异很大，单倍型之间变化很大。我们详细描述了一种单倍型，表明有两个单一的BG基因，一个在2号染色体上，另一个在16号染色体上的主要组织相容性复合体（BF-BL区），以及一个BG基因家族在BG区附近的串联阵列中。这些基因在细胞和组织中具有特异性表达，但总体上在造血细胞或组织中表达。这两个单基因具有相对稳定的进化历史，但BG区域经历动态扩张和收缩，产生杂交基因。因此，鸡BG基因似乎比它们在哺乳动物中最接近的同源物进化得更快，这可能是由于来自病原体的压力增加。
Many genes important in immunity are found as multigene families. The butyrophilin genes are members of the B7 family, playing diverse roles in co-regulation and perhaps in antigen presentation. In humans, a fixed number of butyrophilin genes are found in and around the major histocompatibility complex (MHC), and show striking association with particular autoimmune diseases. In chickens, BG genes encode homologues with somewhat different domain organisation. Only a few BG genes have been characterised, one involved in actin-myosin interaction in the intestinal brush border, and another implicated in resistance to viral diseases. We characterise all BG genes in B12 chickens, finding a multigene family organised as tandem repeats in the BG region outside the MHC, a single gene in the MHC (the BF-BL region), and another single gene on a different chromosome. There is a precise cell and tissue expression for each gene, but overall there are two kinds, those expressed by haemopoietic cells and those expressed in tissues (presumably non-haemopoietic cells), correlating with two different kinds of promoters and 5′ untranslated regions (5′UTR). However, the multigene family in the BG region contains many hybrid genes, suggesting recombination and/or deletion as major evolutionary forces. We identify BG genes in the chicken whole genome shotgun sequence, as well as by comparison to other haplotypes by fibre fluorescence in situ hybridisation, confirming dynamic expansion and contraction within the BG region. Thus, the BG genes in chickens are undergoing much more rapid evolution compared to their homologues in mammals, for reasons yet to be understood. Many immune genes are multigene families, presumably in response to pathogen variation. Some multigene families undergo expansion and contraction, leading to copy number variation (CNV), presumably due to more intense selection. Recently, the butyrophilin family in humans and other mammals has come under scrutiny, due to genetic associations with autoimmune diseases as well as roles in immune co-regulation and antigen presentation. Butyrophilin genes exhibit allelic polymorphism, but gene number appears stable within a species. We found that the BG homologues in chickens are very different, with great changes between haplotypes. We characterised one haplotype in detail, showing that there are two single BG genes, one on chromosome 2 and the other in the major histocompatibility complex (BF-BL region) on chromosome 16, and a family of BG genes in a tandem array in the BG region nearby. These genes have specific expression in cells and tissues, but overall are expressed in either haemopoietic cells or tissues. The two singletons have relatively stable evolutionary histories, but the BG region undergoes dynamic expansion and contraction, with the production of hybrid genes. Thus, chicken BG genes appear to evolve much more quickly than their closest homologs in mammals, presumably due to increased pressure from pathogens.
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影响因子：
10.7
作者：
Castresana, J
通讯作者：
Castresana, J
DOI：
10.1073/pnas.1010647108
发表时间：
2011-03-15
影响因子：
11.1
作者：
Bas, Anna;Swamy, Mahima;Hayday, Adrian C.
通讯作者：
Hayday, Adrian C.
DOI：
10.1073/pnas.1010890108
发表时间：
2011-02-22
影响因子：
11.1
作者：
Barbee, Susannah D.;Woodward, Martin J.;Hayday, Adrian C.
通讯作者：
Hayday, Adrian C.
影响因子：
4.4
作者：
Canavez, F;Young, NT;Parham, P
通讯作者：
Parham, P
影响因子：
11.4
作者：
GUILLEMOT, F;BILLAULT, A;AUFFRAY, C
通讯作者：
AUFFRAY, C