Gene HI1472 of Haemophilus influenzae Rd is a novel gene involved in DNA repair.

A chimeric plasmid, pJPuvr4, consists of a 16.7 kbp Haemophilus influenzae Rd chromosomal DNA insert at the EcoRI site of vector pJ1-8. This plasmid complements the UV and gamma ray sensitivity of the mutant strain MBH4. This plasmid carries the wild type allele of gene uvr4 which was localised to a 3.8 kbp DraI fragment, with an internal EcoRI site. Partial sequencing of the gene and its alignment with the published genome sequence of H. influenzae Rd revealed uvr4 to be HI1472. HI1472 is a putatively identified open reading frame (ORF), which has been assigned no function so far. The partial sequence did show nt database match with 3D exon of N cadherin gene of homosepians and moaA gene of H. influenzae. Cadherins are involved in cell adhesion, cell to cell contact and morphogenesis in homosepians and moaA gene codes for molybdenum biosynthesis subunitA. This report implicates HI1472 of Haemophilus influenzae Rd in DNA repair. Nucleotide sequence obtained for the gene uvr4 was compared with the published sequence of gene HI1472. A wild type strain variation was observed at the 592nd nucleotide position corresponding to a change from aspartic acid to threonine.

Dissimilar Deletion In DMD Gene Of Two Brothers : A Case Study.

Two brothers who are affected by DMD were studied with respect to CPK assay, muscle biopsy and deletion analysis of their DNA. The severity of phenotype in these two brothers is comparable. Onset of the disease in both the cases was at 4 years of age. CPK values obtained at the age of 10 years for the elder brother and 6years for the younger one were 2550 IU and 1650 IU respectively. Muscle biopsy of the patients indicated dystrophy. PCR analysis of the patient's DNA was carried out for deletion detection in DMD gene. The deletion pattern observed for these two cases was found to be quite different from each other. In case of the elder brother, deletion was found to be expanding exons 8-13 whereas, for the younger brother exons 8-13 as well as exons 43-45 were found to be deleted.

A Report On Higher Frequency Of DMD Gene Deletion In The Indian Subcontinent.

Duchenne Muscular Dystrophy (DMD) gene analysis for 25 unrelated patients from Western India using PCR screening for 14 exons and the promoter region was carried out. Intragenic deletions were detected in 18 patients and most of them were located at the 3' hot spot region of the gene indicating that this part of the gene is more deletion prone in the Indian population from Western India as well. The frequency of deletions observed in the present study is 72%.

Chimeric plasmid transformation in Haemophilus influenzae.

Fate of 32P-labelled pJ1-8N19 DNA was followed in the mutant strain N19 and wild type H. influenzae Rd, during post-uptake incubation. Integration of the insert fragment carrying novr gene into the host genome was measured at various time intervals during post-uptake incubation. Negligible amount of label transfer and no detectable transfer of biological activity (novr) was observed in mutant strain N19 compared to wild type strain Rd. These observations correlated poor extra chromosomal establishments of the donor plasmid in the mutant strain N19.

Genetic transformation in bacteria.

Certain species of bacteria can become competent to take up high molecular weight DNA from the surrounding medium. DNA homologous to resident chromosomal DNA is transported, processed and recombined with the resident DNA. There are some variations in steps leading to transformation between Gram-positive bacteria like biplococcus pneumoniae and Gram-negative bacteria represented by Haemophilus influenzae but the integration is by single-strand displacement in both cases. Plasmid (RSF0885) transformation is low in Haemophilus influenzae but this is increased significantly if (homologous) chromosomal DNA is spliced to plasmid DNA. In Haemophilus influenzae, rec1 function is required for peak transformation with chimeric plasmids. Chimeric plasmid fixed presumably extrachromosomally undergoes frequent recombination between homologous segments contained in resident chromosome and the plasmid.

A new DNA-cloning vector for Haemophilus influenzae Rd.

A new, high-efficiency, DNA-cloning vector pJ1-8 was derived in two steps from the chimeric plasmid pD7 consisting of RSF 0885 (ampr) and Haemophilus influenzae chromosomal DNA. pJl-8 has only one EcoRI site and a molecular weight of only 2.5 × 106. No detectable ampr transformation was obtained with pJl-8 DNA. However, ampr transformation increases markedly if Haemophilus influenzae chromosomal DNA segments are spliced into it, providing a very facile assay for detecting inserts.