Jiménez-Marín Angeles, Yubero Noemí, Esteso Gloria, Moreno Angela, de las Mulas Juana Martín, Morera Luis, Llanes Diego, Barbancho Manuel, Garrido Juan J
Unidad de Marcadores Genéticos Moleculares, Departamento de Genética, Universidad de Córdoba, Campus de Rabanales, 14071, Córdoba, Spain.
Gene. 2008 Jan 31;408(1-2):9-17. doi: 10.1016/j.gene.2007.10.016. Epub 2007 Oct 22.
Integrins are heterodimeric cell adhesion molecules with major roles in a variety of biological processes ranging from cell migration to tissue organization, immune and non-immune defense mechanisms and oncogenic transformation. Members of the beta(3) integrin subfamily are composed of a beta(3) subunit (CD61) non-covalently associated with two alpha subunits, alpha(IIb) (CD41) and alpha(v) (CD51), to constitute a group of transmembrane glycoproteins that participate in many physiologically important events. This investigation has focused on the molecular characterization of the cDNA encoding the porcine beta(3) integrin subunit. The deduced 762-amino acid sequence was 93, 92, 91, 89, 79 and 73% homologous to human, dog, rabbit, mouse, chicken and Xenopus laevis CD61 protein, respectively. Porcine CD61 molecule shares many structural features with human CD61, including a region containing a metal ion-dependent adhesion site (MIDAS) folding into an I domain-like structure. Through PCR-SSCP analysis and sequencing, six polymorphic positions were detected in the cDNA sequence of porcine CD61, and their frequencies were observed from a collection of 47 pigs. Expression analysis was done at two different levels: expression of the CD61 mRNA by RT-PCR and localization of the protein by immunohistochemistry. Our results show that CD61 transcripts were detected mainly in platelets and hematopoietic tissues. The immunohistochemical tissue localization of CD61 protein by a specific monoclonal antibody against CD61 recombinant protein showed that CD61 was expressed on vascular and non-vascular smooth muscle, epithelium and myeloid cells, being undetectable in cells of the lymphoid lineage. Furthermore, pulmonary intravascular macrophages (PIM), a subpopulation of macrophages which seem to play an important role in blood clearance, expressed much more CD61 when compared to pulmonary alveolar macrophages (PAM). The knowledge of the structure and distribution of the CD61 provides insight into the physiological function of the porcine beta(3) integrins and should be of importance in understanding the role of this integrin family in biological processes.
整合素是异源二聚体细胞黏附分子，在从细胞迁移到组织构建、免疫和非免疫防御机制以及致癌转化等多种生物学过程中发挥主要作用。β(3)整合素亚家族成员由一个β(3)亚基（CD61）与两个α亚基非共价结合组成，这两个α亚基分别是α(IIb)（CD41）和α(v)（CD51），共同构成一组参与许多生理重要事件的跨膜糖蛋白。本研究聚焦于编码猪β(3)整合素亚基的cDNA的分子特征。推导的762个氨基酸序列与人类、犬、兔、小鼠、鸡和非洲爪蟾的CD61蛋白分别具有93%、92%、91%、89%、79%和73%的同源性。猪CD61分子与人类CD61具有许多结构特征，包括一个含有金属离子依赖性黏附位点（MIDAS）的区域，该区域折叠成类似I结构域的结构。通过PCR-SSCP分析和测序，在猪CD61的cDNA序列中检测到六个多态性位点，并从47头猪的群体中观察到它们的频率。在两个不同水平上进行了表达分析：通过RT-PCR检测CD61 mRNA的表达，通过免疫组织化学检测蛋白的定位。我们的结果表明，CD61转录本主要在血小板和造血组织中检测到。用针对CD61重组蛋白的特异性单克隆抗体对CD61蛋白进行免疫组织化学定位显示，CD61在血管和非血管平滑肌、上皮细胞和髓样细胞上表达，在淋巴谱系细胞中未检测到。此外，肺血管内巨噬细胞（PIM）是巨噬细胞的一个亚群，似乎在血液清除中起重要作用，与肺泡巨噬细胞（PAM）相比，其表达的CD61要多得多。对CD61结构和分布的了解有助于深入了解猪β(3)整合素的生理功能，对于理解该整合素家族在生物学过程中的作用具有重要意义。
