The divergence and positive selection of the plant‐specific BURP‐containing protein family

BURP domain‐containing proteins belong to a plant‐specific protein family and have diverse roles in plant development and stress responses. However, our understanding about the genetic divergence patterns and evolutionary rates of these proteins remain inadequate. In this study, 15 plant genomes were explored to elucidate the genetic origins, divergence, and functions of these proteins. One hundred and twenty‐five BURP protein‐encoding genes were identified from four main plant lineages, including 13 higher plant species. The absence of BURP family genes in unicellular and multicellular algae suggests that this family (1) appeared when plants shifted from relatively stable aquatic environments to land, where conditions are more variable and stressful, and (2) is critical in the adaptation of plants to adverse environments. Promoter analysis revealed that several responsive elements to plant hormones and external environment stresses are concentrated in the promoter region of BURP protein‐encoding genes. This finding confirms that these genes influence plant stress responses. Several segmentally and tandem‐duplicated gene pairs were identified from eight plant species. Thus, in general, BURP domain‐containing genes have been subject to strong positive selection, even though these genes have conformed to different expansion models in different species. Our study also detected certain critical amino acid sites that may have contributed to functional divergence among groups or subgroups. Unexpectedly, all of the critical amino acid residues of functional divergence and positive selection were exclusively located in the C‐terminal region of the BURP domain. In conclusion, our results contribute novel insights into the genetic divergence patterns and evolutionary rates of BURP proteins.     

Genome-wide identification of the BURP domain-containing genes in Phaseolus vulgaris

Plant-specific BURP domain-containing proteins have an essential role in the plant''s development and stress responses. Although BURP domain-containing proteins have been identified in several plant species, genome-wide analysis of the BURP gene family has not been investigated in the common bean. In the present study, we identified 11 BURP family members in the common bean (Phaseolus vulgaris) genome with a comprehensive in silico analysis. Pairwise alignment and phylogenetic analyses grouped PvBURP members into four subfamilies [RD-22 like (3), PG1β-like (4), BNM2-like (3), and USP-like (1)] according to their amino acid motifs, protein domains and intron–exon structure. The physical and biochemical characteristics of amino acids, motif and intron–exon structure, and cis-regulatory elements of BURPs members were determined. Promoter regions of BURP members included stress, light, and hormone response-related cis-elements. Therefore, expression profiles of PvBURP genes were identified with in silico tools and qRT-PCR analyses under stress (salt and drought) and hormone treatment (ABA, IAA) in the current study. While significant activity changes were not observed in BURP genes in RNA-seq data sets related to salt stress, it was determined that some BURP genes were expressed differently in those with drought stress. We identified 12 different miRNA, including miRNA395, miRNA156, miRNA169, miRNA171, miRNA319, and miRNA390, targeting the nine PvBURP genes using two different in silico tools based on perfect or near‐perfect complementarity to their targets. Here we present the first study to identify and characterize the BURP genes in common bean using whole-genome analysis, and the findings may serve as a reference for future functional research in common bean.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12298-021-01052-9.     

Genome-scale identification of Soybean BURP domain-containing genes and their expression under stress treatments

Background  

Multiple proteins containing BURP domain have been identified in many different plant species, but not in any other organisms. To date, the molecular function of the BURP domain is still unknown, and no systematic analysis and expression profiling of the gene family in soybean (Glycine max) has been reported.     

SCB1, a BURP-domain protein gene,from developing soybean seed coats

We describe a gene, SCB1 (Seed Coat BURP-domain protein 1), that is expressed specifically within the soybean (Glycine max [L.] Merrill) seed coat early in its development. Northern blot analysis and mRNA in situ hybridization revealed novel patterns of gene expression during seed development. SCB1 mRNA accumulated first within the developing thick-walled parenchyma cells of the inner integument and later in the thick- and thin-walled parenchyma cells of the outer integument. This occurred prior to the period of seed coat maturation and seed filling and before either of the layers started to degrade. SCB1 may therefore play a role in the differentiation of the seed coat parenchyma cells. In addition, the protein product appears to be located within cell walls. The SCB1 gene codes for a new member of a class of modular proteins that possess a carboxy-terminal BURP domain and a variety of different repeated sequences. The sequence of the genomic clone revealed the insertion of a Tgm transposable element in the upstream promoter region but it is not certain whether it contributes to the tissue-specific pattern of SCB1 expression.     

Central nervous system, uterus, heart, and leukocyte expression of the LOXL3 gene, encoding a novel lysyl oxidase-like protein

A BLASTN search using the mouse lor-2 cDNA identified three overlapping ESTs (AI752772, AA852888, and R55706) in the GenBank database. These expressed sequence tags were assembled into a contig of 3121 nucleotides with an open reading frame of 2262 bp. The encoded putative polypeptide of 754 amino acids presented all structural characteristics of the lysyl oxidase (LOX) enzyme family, a copper-binding site with four histidyl residues, the lysyl and tyrosyl residues known to be involved in LOX enzyme in the formation of the quinone cofactor and surrounding sequences, and the cytokine receptor-like domain. In addition, four scavenger receptor cysteine-rich (SRCR) domains were found in the N-terminal region of the protein. The gene encoding this new cDNA, which we have referred to as human lysyl oxidase-like 3 (humanLOXL3), has been mapped to chromosome 2p13.3, overlapping at its 3' end the HtrA2 serine protease gene. The structure of the humanLOXL3 gene was deduced from the BAC clone bac91a19 sequence and contained 14 exons. The expression pattern of this new member of the LOX gene family appears to be different from that of the LOX and LOX-like genes, as the central nervous system, neurons, and also leukocytes expressed humanLOXL3. A BLASTN search of the human EST database indicated the presence of ESTs, corresponding to alternative splice variants of LOXL3, that lacked exon 5 and exon 8. The putative resulting protein retained the region encoding the structural and functional elements of the amine oxidase but the second and fourth SRCR domains were truncated and the potential BMP-1 cleavage site was not present. The presence of domains unrelated to the traditional amine oxidase activity is a strong indication that humanLOXL3 might fulfill other functions in addition to intrinsic enzyme activity.     

The human HERC family of ubiquitin ligases: novel members, genomic organization, expression profiling, and evolutionary aspects

The HERC family of ubiquitin ligases is characterized by the presence of a HECT domain and one or more RCC1-like domains. We report the identification of two novel members, HERC4 and HERC6, and subdivide the family into one group of two large and one group of four small members according to protein size and domain structure. The small members share a similar genomic organization, three of them mapping to chromosomal region 4q22, indicating strong evolutionary cohesions. Phylogenetic analysis reveals that the HERC ancestor emerged in nematodes and that the family expanded throughout evolution. The mRNA expression pattern of the small human members was found to be diverse in selected tissues and cells; overexpressed proteins display a similar cytosolic distribution. These data indicate that the HERC family members exhibit similarities in many aspects, but also sufficient differences indicating functional diversity.     

A comprehensive expression analysis of the Arabidopsis proline-rich extensin-like receptor kinase gene family using bioinformatic and experimental approaches

The Arabidopsis proline-rich extensin-like receptor kinase (PERK) family consists of 15 predicted receptor kinases. A comprehensive expression analysis was undertaken to identify overlapping and unique expression patterns within this family relative to their phylogeny. Three different approaches were used to study AtPERK gene family expression, and included analyses of the EST, MPSS and NASCArrays databases as well as experimental RNA blot analyses. Some of the AtPERK members were identified as tissue-specific genes while others were more broadly expressed. While in some cases there was a good association between these different expression patterns and the position of the AtPERK members in the kinase phylogeny, in other cases divergence of expression patterns was seen. The PERK expression data identified by the bioinformatics and experimental approaches were found generally to show similar trends and supported the use of data from large-scale expression studies for obtaining preliminary expression data. Thus, the bioinformatics survey for ESTs and microarrays is a powerful comprehensive approach for obtaining a genome-wide view of genes in a multigene family.     

BURP蛋白家族研究进展

BURP蛋白家族是植物界中广泛存在的比较保守的结构基因家族,在胚胎形成和种子发育过程中具有功能.对BURP蛋白家族的结构特征及其4个亚家族成员的功能进行了综述.     

定位于染色体9p21-22的一个新基因UBAP1的克隆测序及在鼻咽癌中的表达分析

 在染色体 9p2 1 2 2鼻咽癌杂合性丢失 (lossofheterozygosity,LOH)高频区 ,应用EST介导的定位 侯选克隆策略 ,用RT PCR及Northern杂交检测了 2 2个表达序列标记 (expressedsequencetag ,EST)在鼻咽癌细胞株HNE1和原代培养的正常鼻咽上皮细胞中的表达差异 ,并对其中一个在鼻咽癌细胞株HNE1中表达下调的EST检测了在鼻咽癌活检组织中的表达 .用生物信息学方法获得其全长cDNA序列 ,GenBank登录号AF2 2 2 0 4 3.该基因cDNA全长 2 70 1bp ,其开放阅读框 (openreadingframe ,ORF)编码一个含 50 2个氨基酸、分子量为 55kD的碱性蛋白质 ,在蛋白羧基端含有 2个连续的重要UBA功能域 (ubiquitinassociateddomain) ,属于遍在蛋白相关蛋白家族的一个新成员 ,经国际人类基因命名委员会同意 ,将其命名为UBAP1 (ubiquitinassociatedprotein 1 ) .Northern表达分析显示UBAP1在所检测的人组织中广泛表达 ,但在人的心脏、骨骼肌及肝脏中的表达较强 .UBAP1基因在63 2 % ( 1 2 1 9)的鼻咽癌活检组织中表达下调 .UBAP1基因作为一个遍在蛋白相关蛋白家族的新成员 ,结合其在 9p的重要定位信息 ,有必要进一步研究其表达下调参与鼻咽癌发生发展的可能机制 .     

Application of comparative genomics in developing molecular markers tightly linked to the virus resistance gene Rsv4 in soybean.

The Rsv4 gene confers resistance to all the known strain groups of soybean mosaic virus in soybean (Glycine max (L.) Merr.). To construct a fine genetic map near Rsv4 in soybean, we employed a comparative genomics approach that used genome sequence information of the model legume Lotus japonicus. Sequences of the soybean expressed sequence tags (ESTs) AI856415 and BF070293 mapping to one side of the Rsv4 gene showed high similarity with gene sequences of the transformation-competent artificial chromosome (TAC) clone LjT32P24 of Lotus. LjT32P24 is tightly linked to another sequenced TAC clone, LjT26I01, in Lotus. A new marker, AW307114A, developed from soybean EST AW307114, which is homologous to a Lotus gene within LjT26I01, was mapped to the other side of the Rsv4 gene. The identification of the microsyntenic relationship facilitated the development of additional 2 EST markers between BF070293-S and AW307114A bracketing the Rsv4 gene. Several other markers developed in this study were mapped to putative homoeologous or duplicated chromosomal regions in soybean. Alignment between the soybean maps indicated that Rsv4 is located near a local chromosomal rearrangement. This targeted comparative mapping serves to provide a foundation for marker-assisted selection and cloning of the Rsv4 gene.     

Gene expression profile of human bone marrow stromal cells: high-throughput expressed sequence tag sequencing analysis

Human bone marrow stromal cells (HBMSC) are pluripotent cells with the potential to differentiate into osteoblasts, chondrocytes, myelosupportive stroma, and marrow adipocytes. We used high-throughput DNA sequencing analysis to generate 4258 single-pass sequencing reactions (known as expressed sequence tags, or ESTs) obtained from the 5' (97) and 3' (4161) ends of human cDNA clones from a HBMSC cDNA library. Our goal was to obtain tag sequences from the maximum number of possible genes and to deposit them in the publicly accessible database for ESTs (dbEST of the National Center for Biotechnology Information). Comparisons of our EST sequencing data with nonredundant human mRNA and protein databases showed that the ESTs represent 1860 gene clusters. The EST sequencing data analysis showed 60 novel genes found only in this cDNA library after BLAST analysis against 3.0 million ESTs in NCBI's dbEST database. The BLAST search also showed the identified ESTs that have close homology to known genes, which suggests that these may be newly recognized members of known gene families. The gene expression profile of this cell type is revealed by analyzing both the frequency with which a message is encountered and the functional categorization of expressed sequences. Comparing an EST sequence with the human genomic sequence database enables assignment of an EST to a specific chromosomal region (a process called digital gene localization) and often enables immediate partial determination of intron/exon boundaries within the genomic structure. It is expected that high-throughput EST sequencing and data mining analysis will greatly promote our understanding of gene expression in these cells and of growth and development of the skeleton.     

Organisation and structural evolution of the rice glutathione <Emphasis Type="Italic">S</Emphasis>-transferase gene family

Glutathione S-transferases (GSTs) comprise a large family of key defence enzymes against xenobiotic toxicity. Here we describe the comprehensive characterisation of this important multigene family in the model monocot species rice [Oryza sativa (L.)]. Furthermore, we investigate the molecular evolution of the family based on the analysis of (1) the patterns of within-genome duplication, and (2) the phylogenetic relationships and evolutionary divergence among rice, Arabidopsis, maize and soybean GSTs. By in-silico screening of the EST and genome divisions of the Genbank/EMBL/DDBJ database we have isolated 59 putative genes and two pseudogenes, making this the largest plant GST family characterised to date. Of these, 38 (62%) are represented by genomic and EST sequences and 23 (38%) are known only from their genomic sequences. A preliminary survey of EST collections shows a large degree of variability in gene expression between different tissues and environmental conditions, with a small number of genes (13) accounting for 80% of all ESTs. Rice GSTs are organised in four main phylogenetic classes, with 91% of all rice genes belonging to the two plant-specific classes Tau (40 genes) and Phi (16 genes). Pairwise identity scores range between 17 and 98% for proteins of the same class, and 7 and 21% for interclass comparisons. Rapid evolution by gene duplication is suggested by the discovery of two large clusters of 7 and 23 closely related genes on chromosomes 1 and 10, respectively. A comparison of the complete GST families in two monocot and two dicot species suggests a monophyletic origin for all Theta and Zeta GSTs, and no more than three common ancestors for all Phi and Tau genes.Electronic Supplementary Material Supplementary material is available in the online version of this article at Communicated by M.-A. Grandbastien     

A conserved BURP domain defines a novel group of plant proteins with unusual primary structures

We have identified a new class of plant proteins containing a common C-terminal region, which we have termed the BURP domain. These proteins are defined not only by the BURP domain, but also by the overall similarity in their modular construction. The BURP domain proteins consist of either three or four modules: (i) an N-terminal hydrophobic domain – a presumptive transit peptide, joined to (ii) a short conserved segment or other short segment, (iii) an optional segment consisting of repeated units which is unique to each member, and (iv) the C-terminal BURP domain. These individual modules appear to be combined to form two main classes of BURP domain proteins. The BURP domain proteins, despite the similarities in their primary structural features, show no obvious similarities in the tissues or conditions under which they are expressed. The presence of the conserved BURP domain in diverse plant proteins suggests an important and fundamental functional role for this domain. Received: 30 April 1998 / Accepted: 10 June 1998     

普通烟草LBD基因家族的全基因组序列鉴定与表达分析

LBD是一类具有LOB(lateral organ boundaries)结构域的基因家族,在植物发育过程中起到非常重要的作用。采用生物信息学方法,根据拟南芥LBD基因序列鉴定了普通烟草基因组中的LBD基因,并对家族成员进行了序列特征、系统发育和表达谱分析。结果表明:普通烟草基因组中共有98个LBD基因成员,其基因结构相对简单,一般含有1~3个外显子。LBD基因家族可分成I和II两大类,两类均含有CX_2CX_6CX_3C保守结构域,但II类不含有LX_6LX_3LX_6L形成的"卷曲螺旋"二级结构,根据与拟南芥LBD蛋白构建的系统发育树则可细分成5个亚家族(Ia、Ib、Ic、Id和II)。将LBD基因与表达序列标签(EST)比对,发现36个基因有EST证据;EST、芯片数据和转录组数据分析表明:LBD基因具有不同的组织表达模式,部分基因表现出组织特异性。这些研究结果为普通烟草LBD基因家族功能的深入研究奠定了基础。