Characterization of two duplicate hoxa2 genes in Morone saxatilis : identification of CIS-regulatory elements by comparative DNA sequence analysis / by Jamie L. Vernon.
| Author/creator | Vernon, Jamie L. author. |
| Other author | Scemama, Jean-Luc, degree supervisor. |
| Other author | East Carolina University. Department of Biology. |
| Format | Theses and dissertations |
| Production | 2005. |
| Description | viii, 147 leaves : illustrations (some color) ; 28 cm |
| Supplemental Content | Access via ScholarShip |
| Subjects |
| Summary | Hox genes are characterized by their clustered organization, in which up to 11 evolutionarily conserved genes are tightly-linked and duplicated on between 4 and 7 different chromosomes in tetrapods and teleosts, respectively. In addition to their clustered organization, they are expressed in embryos colinearally with respect to their arrangement along the chromosomes, such that genes located at the 3' end of the clusters are expressed earlier and more anteriorly than those located at the 5' end of the clusters, which are expressed later and more posteriorly. Our laboratory is interested in determining whether this linkage between physical location and expression pattern is conserved evolutionarily. Toward this end, we are involved in the characterization of the Hox cluster architecture in the teleost, Morone saxatilis (striped bass), which is a member of the order Perciformes - an order that is the most speciated among vertebrates. We have completed the molecular genetic characterization of genes from at least five separate Hox clusters. Analysis of striped bass hoxb2a has revealed a conspicuously divergent pattern of expression. Prior to this discovery, members of paralagous group 2 in several vertebrate species were classified based on a conserved devlopmental pattern of expression, which includes expression in the hindbrain and neural crest cells migrating into the branchial arches. While expression of striped bass hoxb2a is conserved in the hindbrain, no expression is detected in migrating neural crest cells. Here I describe analysis of a [lambda]EMBL3 clone with a 17.4-kb insert that contains sequence from 3 different genes belonging to the HoxAa cluster. DNA sequence analysis has resulted in the classification of one of these genes as hoxa2a. In addition, reverse transcription polymerase chain reactions using primers designed to amplify the hoxa2a cDNA have identified a third member of paralogous group 2 that is expressed in striped bass embryos 24 hours postfertilization (hpf). Based on sequence comparisons, this gene has been classified as hoxa2b. Expression analysis by in situ hybridization supports the classifications of these genes and has established that hoxa2a and hoxa2b are expressed in cells migrating from the hindbrain into the branchial arches. In addition, genomic sequence analysis of the hoxa2a genomic sequence along with other members of paralogous group 2 has identified several conserved putative transcription factor binding sites that may be involved in regulating the observed patterns of expression for striped bass hoxa2a and hoxb2a. |
| General note | Presented to the faculty of the Department of Biology. |
| General note | Advisor: Jean-Luc Scemama |
| Dissertation note | M.S. East Carolina University 2005 |
| Bibliography note | Includes bibliographical references (leaves 120-129). |
| Genre/form | Academic theses. |
| Genre/form | Academic theses. |
| Genre/form | Thèses et écrits académiques. |
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