Genome Wide Identification and Comparative Analysis of the Serpin Gene Family in Brachypodium and Barley

Serpins (serine protease inhibitors) constitute one of the largest and most widely distributed superfamilies of protease inhibitors and have been identified in nearly all organisms. To gain significant insights, a comprehensive in silico analysis of the serpin gene family was carried out in the model plant for temperate grasses Brachypodium distachyon and barley Hordeum vulgare using bioinformatic tools at the genome level for the first time. We identified a total of 27 BdSRPs and 25 HvSRP genes in Brachypodium and barley, respectively, showing an unexpectedly high gene number in these model plants. Gene structure, conserved motifs and phylogenetic comparisons of serpin genes supported the role of duplication events in the expansion and evolution of serpin gene family. Further, purifying selection pressure was found to be a main driving force in the evolution of serpin genes. Genome synteny analysis indicated that BdSRP genes were present in syntenic regions of barley, rice, sorghum and maize, suggesting that they evolved before the divergence of these species from common ancestor. The distinct expression pattern in specific tissues further suggested a specialization of functions during development and in plant defense. These results suggest that the LR serpins (serpins with Leu-Arg residues at P2–P1′) identified here can be utilized as candidates for exploitation in disease resistance, pest control and preventing stress-induced cell death. Additionally, serpins were identified that could lead to further research aimed at validating and functionally characterizing the role of potential serpin genes from other plants.

4G/4G PAI-1 gene variant in a patient with non-healing ulcers

Plasminogen activator inhibitor is a serine protease inhibitor from the serpin gene family that modulates fibrin clot breakdown.PAI-1 irreversibly inhibits tissue plasminogen activator (t-PA) and urokinase plasminogen activator (u-PA) from activatingplasminogen. PAI-1 also inhibits integrin-vitronectin and vitronectin-vitronectin interactions that are essential for cell migration,adhesion, and angiogenesis. We describe a patient, who developed chronic non-healing ulcers after minimal trauma to severalareas of his body. Genetic testing revealed the 4G/4G homozygous genotype for the polymorphism in the promoter regionof the PAI-1 gene. Increased PAI-1 activity prevents the breakdown of the fibrin clot and cell migration to remodel damagedtissue. A combination of poor clot fibrinolysis and cell recruitment to the site of injury may explain our patient’s non-healingulcers following minor traumatic injury. Early treatment with excision and skin grafting may benefit patients presenting withnon-healing ulcers and the homozygous 4G/4G PAI-1 variant. To our knowledge, there have been no reports in the literatureassociating PAI-1 overexpression and chronic non-healing wounds.

Transcriptional Expression of Serpin-6 Gene in Bombyx Mori Larval after Infection of Bacteria at Different Developmental Stages

Serpins can block different steps in the activation cascade of prophenoloxidase (proPO) system, and play an important role in immunity of insect. In this paper, Haemolymph was collected from the 4th molting, newly moulted 5th instar and day-3 fifth instar larval challenged by lipopolysaccharide (LPS) or Bacillus thuringiensis, respectively. The results revealed that the transcriptional level of Bmserpin-6 in different developmental stages showed a trend of rise first, then fall. Bmserpin-6 of the 4th molting larva expressed highest at 6h post-infection with LPS and 3h post-infection with Bacillus thuringiensis. Bmserpin-6 of newly moulted 5th instar larva expressed highest at 9h post-infection with LPS and 6h post-infection with Bacillus thuringiensis. Bmserpin-6 of day-3 fifth instar larva expressed highest at 9h post-infection with Bacillus thuringiensis. Bmserpin-6 was all highly induced and highly expressed in haemolymph of larval at different developmental stages. But The time to arrive the highest transcriptional level was different. This is inferred that the Serpin gene may play an important role in immunity of Bombyx mori.