Identification of a homozygous splice site mutation in the dynein axonemal light chain 4 gene on 22q13.1 in a large consanguineous family from Pakistan with congenital mirror movement disorder

Mirror movements (MRMV) are involuntary movements on one side of the body that mirror voluntary movements on the opposite side. Congenital mirror movement disorder is a rare, typically autosomal-dominant disorder, although it has been suspected that some sporadic cases may be due to recessive inheritance. Using a linkage analysis and a candidate gene approach, two genes have been implicated in congenital MRMV disorder to date: DCC on 18q21.2 (MRMV1), which encodes a netrin receptor, and RAD51 on 15q15.1 (MRMV2), which is involved in the maintenance of genomic integrity. Here, we describe a large consanguineous Pakistani family with 11 cases of congenital MRMV disorder reported across five generations, with autosomal recessive inheritance likely. Sanger sequencing of DCC and RAD51 did not identify a mutation. We then employed microarray genotyping and autozygosity mapping to identify a shared region of homozygosity-by-descent among the affected individuals. We identified a large autozygous region of ~3.3 Mb on chromosome 22q13.1 (Chr22:36605976?39904648). We used Sanger sequencing to exclude several candidate genes within this region, including DMC1 and NPTXR. Whole exome sequencing was employed, and identified a splice site mutation in the dynein axonemal light chain 4 gene, DNAL4. This splice site change leads to skipping of exon 3, and omission of 28 amino acids from DNAL4 protein. Linkage analysis using Simwalk2 gives a maximum Lod score of 6.197 at this locus. Whether or how DNAL4 function may relate to the function of DCC or RAD51 is not known. Also, there is no suggestion of primary ciliary dyskinesis, situs inversus, or defective sperm in affected family members, which might be anticipated given a putative role for DNAL4 in axonemal-based dynein complexes. We suggest that DNAL4 plays a role in the cytoplasmic dynein complex for netrin-1-directed retrograde transport, and in commissural neurons of the corpus callosum in particular. This, in turn, could lead to faulty cross-brain wiring, resulting in MRMV.     

Application of novel nanotechnology strategies in plant biotransformation: a contemporary overview

During the past epoch we have gone through the remarkable progress in plant gene transformation technology. The production of transgenic plants is considered as a valuable tool in plant research and the technology is extensively applied in phytomedicines and agricultural research. Gene transformation in plants is normally carried out by Agrobacterium species, application of some chemicals and physical techniques (electroporation, microprojectile, etc.). Now a days with better efficacy and reproducibility, novel technologies for the direct gene transfer like liposome, positively charged liposome (lipofectin) and nanoparticle based delivery systems are used for genetic transformation of plants. In this review, we have enlightened the novel nanotechnologies like liposome, Carbon nano-tube and nanoparticles with their current status and future prospects in transgenic plant development. Moreover, we have also highlighted the limitations of conventional techniques of gene transfer. Furthermore, we have tried to postulate innovative ideas on the footprints of established nanotechnology and chemical based strategy with improved efficacy, reproducibility and accuracy along with less time consumption.     

Decreased gene expression activity as a result of a mutation in the calreticulin gene promoter in a family case of schizoaffective disorder

Accumulating evidence of population association studies support the hypothesis that the high heritability of major psychiatric disorders is a combination of relatively common alleles of modest effect, and rare alleles some with relatively larger effects. We have previously reported low frequency mutations in the proximal promoter of the human calreticulin (CALR) gene that co-occur with the spectrum of major psychiatric disorders. One of those mutations at ?205C>T (rs556992558) was detected in an isolate case of schizoaffective disorder. In the current study, the functional implication of mutation ?205T is studied in the human neuronal cell lines LAN-5, BE(2)-C and HEK-293. In contrast with other mutations in the promoter region which increase gene expression activity, the ?205T mutation significantly decreased gene expression in those cell lines in comparison with the wild-type ?205C nucleotide (p < 0.000001, p < 0.0005, and p < 0.017, respectively). Treatment of the cell lines with the mood-stabilizing drug, valproic acid (VPA) resulted in differential gene expression activity in the mutant ?205T versus the wild-type ?205C construct. VPA increased gene expression activity in both constructs, while a significantly higher expression activity was observed in the mutant construct (p < 0.01), indicative of the creation of a positive effector binding site for VPA as a result of the ?205T mutation. We conclude that deviation from normalcy in the level of CALR in either direction is associated with major psychiatric disorders.     

A semi-empirical glycosylation model of a camelid monoclonal antibody under hypothermia cell culture conditions

The impact of cell culture environment on the glycan distribution of a monoclonal antibody (mAb) has been investigated through a combination of experiments and modeling. A newly developed CHO DUXB cell line was cultivated at two levels of initial Glutamine (Gln) concentrations (0, 4 mM) and incubation temperatures of (33 and 37 °C) in batch operation mode. Hypothermia was applied either through the entire culture duration or only during the post-exponential phase. Beyond reducing cell growth and increasing productivity, hypothermia significantly altered the galactosylation index profiles as compared to control conditions. A novel semi-empirical dynamic model was proposed for elucidating the connections between the extracellular cell culture conditions to galactosylation index. The developed model is based on a simplified balance of nucleotides sugars and on the correlation between sugars’ levels to the galactosylation index (GI). The model predictions were found to be in a good agreement with the experimental data. The proposed empirical model is expected to be useful for controlling the glycoprofiles by manipulating culture conditions.     

Localization of a gene for familial hemophagocytic lymphohistiocytosis at chromosome 9q21.3-22 by homozygosity mapping.

Familial hemophagocytic lymphohistiocytosis (FHL), also known as familial erythrophagocytic lymphohistiocytosis and familial histiocytic reticulosis, is a rare autosomal recessive disorder of early childhood characterized by excessive immune activation. Linkage of the disease gene to an approximately 7.8-cM region between markers D9S1867 and D9S1790 at 9q21.3-22 was identified by homozygosity mapping in four inbred FHL families of Pakistani descent with a combined maximum multipoint LOD score of 6.05. This is the first genetic locus to be described in FHL. However, homozygosity by descent across this interval could not be demonstrated in an additional affected kindred of Arab origin, whose maximum multipoint LOD score was -0.12. The combined sample revealed significant evidence for linkage to 9q markers (LOD score with heterogeneity, 5.00). Identification of the gene(s) involved in the pathogenesis of FHL will contribute to an understanding of the control of T-lymphocyte and macrophage activation, which is central to homeostasis in the immune system.