ABSTRACT
Integrin-ß1-null keratinocytes can adhere to fibronectin through integrin αvß6, but form large peripheral focal adhesions and exhibit defective cell spreading. Here we report that, in addition to the reduced avidity of αvß6 integrin binding to fibronectin, the inability of integrin ß6 to efficiently bind and recruit kindlin-2 to focal adhesions directly contributes to these phenotypes. Kindlins regulate integrins through direct interactions with the integrin-ß cytoplasmic tail and keratinocytes express kindlin-1 and kindlin-2. Notably, although both kindlins localize to focal adhesions in wild-type cells, only kindlin-1 localizes to the integrin-ß6-rich adhesions of integrin-ß1-null cells. Rescue of these cells with wild-type and chimeric integrin constructs revealed a correlation between kindlin-2 recruitment and cell spreading. Furthermore, despite the presence of kindlin-1, knockdown of kindlin-2 in wild-type keratinocytes impaired cell spreading. Our data reveal unexpected functional consequences of differences in the association of two homologous kindlin isoforms with two closely related integrins, and suggest that despite their similarities, different kindlins are likely to have unique functions.
Subject(s)
Antigens, Neoplasm/metabolism , Integrin beta1/metabolism , Integrins/metabolism , Keratinocytes/metabolism , Membrane Proteins/metabolism , Neoplasm Proteins/metabolism , Amino Acid Sequence , Cell Adhesion/physiology , Fibronectins/metabolism , Flow Cytometry , Focal Adhesions , Gene Knockout Techniques , Humans , Integrin beta1/genetics , Keratinocytes/cytology , Membrane Proteins/chemistry , Molecular Sequence Data , Neoplasm Proteins/chemistry , Sequence AlignmentABSTRACT
Molecular breakpoint of the BCR-ABL fusion gene has been characterized for 122 chronic myeloid leukemia patients. Out of 122 cases, 33 b2a2, 69 b3a2, 2 e1a2, and 2 e19a2 cases have been detected. Six coexpressed both b2a2 and b3a2 transcripts. All the coexpressing samples had an A>G polymorphism at the putative splice branchpoint in intron 13. The T>C polymorphism in exon 13, reported to be linked to coexpression, was not present in all the coexpressing patients. No correlation of transcript type with platelet count was detected. Those expressing b2a2 transcript were diagnosed at relatively younger age and with higher white blood cell count, in agreement with other reports. However, the correlation was not statistically significant.
Subject(s)
Fusion Proteins, bcr-abl/genetics , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics , Adult , Base Sequence , DNA Primers , DNA, Neoplasm/genetics , DNA, Neoplasm/isolation & purification , Female , Gene Expression Profiling , Genotype , Humans , India , Introns , Male , Middle Aged , Polymorphism, Genetic , RNA, Neoplasm/genetics , RNA, Neoplasm/isolation & purification , Reverse Transcriptase Polymerase Chain Reaction , Transcription, GeneticABSTRACT
OBJECTIVE: To control the birth of thalassemic children in India. METHODS: Mutations present in the population of eastern India and in carrier parents seeking prenatal diagnosis were detected by the PCR-based technique of ARMS (amplification refractory mutation system) or gap-PCR. To screen for maternal tissue contamination in CVS, haplotypes associated with the beta-globin gene clusters were constructed using six polymorphic restriction sites. Prenatal diagnosis was accomplished by checking presence of parental mutation in the DNA from chorionic villus sampling (CVS) collected at 8 to 10 weeks' gestation by appropriate technique. RESULTS: Six hundred and fifty (650) unrelated beta-thalassemia chromosomes were screened for 11 common mutations to characterize the mutation distribution in this population. Starting from early 2000, 63 families from different parts of West Bengal and from surrounding areas have been offered prenatal counseling for beta-thalassemia. CONCLUSION: The population of this region is conscious and willing to accept prenatal diagnosis as a means of control of thalassemia.
