OsCSN2 orchestrates Oryza sativa L. growth and development through modulation of the GA and BR pathways.

The COP9 signalosome (CSN) is a conserved protein complex found in higher eukaryotes, consisting of eight subunits, and it plays a crucial role in regulating various processes of plant growth and development. Among these subunits, CSN2 is one of the most conserved components within the COP9 signalosome complex. Despite its prior identification in other species, its specific function in Oryza sativa L. (Rice) has remained poorly understood. In this study, we investigated the role of CSN2 in rice using gene editing CRISPR/Cas9 technology and overexpression techniques. We created two types of mutants: the oscsn2 mutant and the OsCSN2-OE mutant, both in the background of rice, and also generated point mutants of OsCSN2 (OsCSN2K64E, OsCSN2K67E, OsCSN2K71E and OsCSN2K104E) to further explore the regulatory function of OsCSN2. Phenotypic observation and gene expression analysis were conducted on plants from the generated mutants, tracking their growth from the seedling to the heading stages. The results showed that the loss and modification of OsCSN2 had limited effects on plant growth and development during the early stages of both the wild-type and mutant plants. However, as the plants grew to 60 days, significant differences emerged. The OsCSN2 point mutants exhibited increased tillering compared to the OsCSN2-OE mutant plants, which were already at the tillering stage. On the other hand, the OsCSN2 point mutant had already progressed to the heading and flowering stages, with the shorter plants. These results, along with functional predictions of the OsCSN2 protein, indicated that changes in the 64th, 67th, 71st, and 104th amino acids of OsCSN2 affected its ubiquitination site, influencing the ubiquitination function of CSN and consequently impacting the degradation of the DELLA protein SLR1. Taken together, it can be speculated that OsCSN2 plays a key role in GA and BR pathways by influencing the functional regulation of the transcription factor SLR1 in CSN, thereby affecting the growth and development of rice and the number of tillers.

Cloning of the Arabidopsis SMAP2 promoter and analysis of its expression activity.

The SMALL ACIDIC PROTEIN (SMAP) gene is evolutionarily indispensable for organisms. There are two copies of the SMAP gene in the Arabidopsis thaliana genome, namely, SMAP1 and SMAP2. The function of SMAP2 is similar to that of SMAP1, and both can mediate 2,4-D responses in the root of Arabidopsis. This study cloned the AtSMAP2 genetic promoter sequence. Two promoter fragments of different lengths were designed according to the distribution of their cis-acting elements, and the corresponding ß- glucuronidase (GUS) expression vector was constructed. The expression activity of promoters of two lengths, 1993 bp and 997 bp, was studied by the genetic transformation in Arabidopsis. The prediction results of cis-acting elements in the promoter show that there are many hormone response elements in 997 bp, such as three abscisic acid response elements ABRE, gibberellin response elements P-box and GARE-motif and auxin response element AuxRR-core. Through GUS histochemical staining and qRT‒PCR analysis, it was found that the higher promoter activity of PAtSMAP2-997, compared to PAtSMAP2-1993, drove the expression of GUS genes at higher levels in Arabidopsis, especially in the root system. The results provide an important basis for subsequent studies on the regulation of AtSMAP2 gene expression and biological functions.

Revision hip arthroplasties with use of the modular S-ROM prosthesis.

OBJECTIVE: The aim of this study was to revision hip arthroplasties in ankylosing spondylitis. MATERIALS AND METHODS: We performed 21 revision hip arthroplasty in 16 patients with ankylosing spondylitis (AS) using S-ROM modular femoral stem. At the final follow-up, all patients were able to ambulate without any walking aids. RESULTS: The mean Harris hip score improved from 57.2 (35 to 74) pre-operatively to 90.2 points (73 to 100) post-operatively, and the outcome was classified as good or excellent in 17 hips (81%). Fixation of the femoral component was classified as stable with bone ingrowth in 15 hips (71.4%), stable with fibrous ingrowth in 2 hips (9.5%), and radiolucent loosening in 4 hips (19.1%). Five hips developed a pedestal at the tip of femoral component. Femoral osteolysis was found in 3 hips (14.2%): 3 hips in Gruen zones 1 and 7, one hip in zone 7, and two hips in zone 1. One hip underwent acetabular revision because of breakage of polyethylene liner, and the well-fixed femoral component was left in situ. Thigh pain developed in 1 patient (6.2%). Kaplan-Meier survival was 81% at 64 months, with radiographic loosening as an end-point when two hips were at risk. CONCLUSION: Satisfactory results of midterm clinical and radiographic follow-up can be achieved using S-ROM modular femoral stem for revision of femoral stem in ankylosing spondylitis.