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H Matsumine

Publications and source records attributed to H Matsumine.

At least 37 records · Page 2Linked to original sources

A loss-of-function mechanism of nigral neuron death without Lewy body formation: autosomal recessive juvenile parkinsonism (AR-JP).

We present a genetic model of selective nigral neuron death without Lewy body formation--autosomal recessive juvenile parkinsonism (AR-JP). Mapping of AR-JP gene to a single recessive locus on chromosome 6q25.2-27 is a strong indication of the idea that a loss-of-function mutation of a single gene is sufficient to cause selective nigral neuron death. The absence of Lewy body formation in AR-JP is important, because most cases of neuron death caused by loss-of-function mechanism are not accompanied by inclusion body. Our findings clearly indicate that nigral cells are critically dependent for their survival on the function of AR-JP protein. This raises an important question of whether or not AR-JP protein contributes to the downstream pathway of cell death in Parkinson's disease.

Cell Death↗

Refinement of the gene locus for autosomal recessive juvenile parkinsonism (AR-JP) on chromosome 6q25.2-27 and identification of markers exhibiting linkage disequilibrium.

Autosomal recessive juvenile parkinsonism (AR-JP) (MIM 600116) is a hereditary neurodegenerative disorder characterized by levodopa-responsive parkinsonism with a mean age at onset of 23.2 years. We recently mapped the AR-JP gene locus to a 17-cM interval on chromosome 6q25.2-27. To further narrow the candidate region of the AR-JP gene, we performed detailed linkage analysis using densely placed genetic markers in this region (D6S437, D6S1581, D6S1579, D6S305, D6S411, SOD2, D6S253, D6S1599, D6S1719 and D6S264). Pairwise linkage analysis revealed the highest cumulative maximal lod score of 9.13 at D6S1579 (theta = 0.05), and multipoint linkage analysis revealed the highest cumulative lod score of 12.4 at the locus 3 cM telomeric to D6S1599. Observation of obligate recombination events narrowed the candidate region to a 13-cM region between D6S1579 and D6S264. Furthermore, we identified two marker loci, D6S1579 and D6S1599, which exhibit strong linkage disequilibrium with the AR-JP locus: chi 2 (2 x n table) = 84.22; P < 0.0001, chi 2 [likelihood-ratio test (LRT)] = 20.66; P < 0.0001, lambda = 0.40 and chi 2 (2 x n table) = 63.37; P < 0.0001, chi 2 (LRT) = 10.32; P < 0.0001, lambda = 0.30, respectively. These results suggest that the candidate region for the AR-JP gene is most likely located near the 4-cM region encompassing D6S1579 and D6S1599.

Adult↗

Neurochemical and neurogenetic correlates of Parkinson's disease.

We discuss neurochemical and neurogenetic correlates of Parkinson's disease (PD) based on the recent progress in the study of its etiology and pathogenesis. Nigral degeneration with the presence of Lewy bodies in the remaining neurons is the pathologic hallmark of PD, and the resultant loss of striatal dopamine is responsible for most of the clinical manifestations. Although the primary cause is still unknown, mitochondrial respiratory failure and oxidative stress appear to be two major contributors to the nigral cell death. Many endogenous and exogenous compounds with structural similarity to MPTP have been postulated as potential neurotoxins inducing nigral cell death in PD, but there is little evidence of accumulation of such compounds in the nigra. Genetic influence has increasingly been recognized as an important risk factor for PD. In this respect, genetic linkage analysis and molecular cloning of the disease genes in familial parkinsonism are of utmost importance today. Recently, the disease gene for one of the autosomal dominant forms of familial PD was identified, and we cloned the gene for an autosomal recessive type of familial parkinsonism that had been mapped to the long arm of chromosome 6 by our group. Information obtained on familial parkinsonism will contribute to the studies on sporadic PD as well.

Brain↗

Early onset parkinsonism with diurnal fluctuation maps to a locus for juvenile parkinsonism.

Early onset parkinsonism with diurnal fluctuation (EPDF) is a dopa-responsive parkinsonism characterized by early onset and improvement of parkinsonian symptoms after sleep. A pathologic study of one case of EPDF showed selective neuronal degeneration in the zona compacta of the substantia nigra without Lewy body formation. To determine the disease locus for EPDF, the authors examined 53 members of 17 EPDF families and analyzed 151 meioses. Multipoint linkage analysis gave a peak lod score of 14.2 at 1.0 cM telomeric to D6S305 and placed the disease locus in the 17-cM interval between D6S437 and D6S253, which is exactly the same position mapped for autosomal recessive juvenile parkinsonism (ARJP; Mendelian inheritance in man 600116). The highest two-point lod score was obtained at D6S305 (10.13 at theta = 0). Haplotype analysis agreed with the result of multipoint analysis. A high proportion of nonconsanguinity (8/17 families), the absence of commonly shared haplotypes, and the widespread geographic distribution of the families' origins suggest that EPDF has multiple founder mutations. The authors concluded that EPDF and ARJP are allelic disorders and should be included in the spectrum of a single-clinicogenetic entity of chromosome 6q-linked parkinsonism. This disease could be characterized by a benign clinical course and relatively selective degeneration of nigral dopaminergic neurons with no Lewy body formation. To determine whether ARJP/EPDF constitutes a significant proportion of familial or sporadic forms of benign early onset parkinsonism will require further study.

Adolescent↗

Pathologic and biochemical studies of juvenile parkinsonism linked to chromosome 6q.

We report the results of pathologic and biochemical studies in a patient with 6q-linked autosomal recessive juvenile parkinsonism (AR-JP). Neuronal loss and gliosis were restricted to the substantia nigra and the locus ceruleus. No Lewy bodies were found, but neurofibrillary tangles and argyrophilic astrocytes were seen in the cerebral cortex and brainstem nuclei. The later findings, which have not been reported previously in AR-JP, suggest the pathologic heterogeneity of 6q-linked AR-JP.

Brain↗

[A 49-year-old man with progressive bulbar palsy and respiratory failure].

We report a 49-year-old man with progressive bulbar palsy and respiratory failure. He was well until his 48 years of the age (December 1994) when he noted a difficulty in speaking in loud voice. In February, 1995, he noted regurgitation of foods to his nose and difficulty in his speech. He was admitted to our service in May 29, 1995. On admission, he was alert and oriented to all spheres and he was not demented. His higher cerebral functions were normal. In cranial nerves, he showed dysarthria and dysphagia; muscle atrophies were seen in the tongue, the bilateral sternocleidomastoid, supraspinatus, and infraspinatus muscles. Fasciculations were seen in these muscles. He showed no muscle weakness in his limbs except for the upper limb girdle muscles, no ataxia, no reflex abnormalities, nor sensory changes. EMG showed neurogenic changes in the affected muscles. MRI of the brain and the spinal cord was entirely normal. He was discharged for out patient follow-up, however, in October of 1995, he noted difficulty in swallowing solid foods. Gastrostomy was placed and he was discharged to his home. In February 11th of 1996, he was found unresponsive and brought into the ER of our hospital. On admission, he was comatose without spontaneous respiration. BP could not be obtained. He was immediately intubated and artificial ventilation was started. On the following morning, he became alert and he was not demented. He continued to show marked dysarthria and dysphagia; again no weakness was noted in the distal parts of the upper and lower extremities. Laboratory examination showed increase in serum CK to 2,173 IU/L and amylase to 2,032 IU/L. He was extubated on February 15th, however, his spontaneous respiration was not suffice to maintain his blood gas. According to his will, he was not placed on respirator and he died on February 24th, 1996. The patient was discussed in a neurological CPC and the chief discussant arrived at the conclusion that the patient had ALS. Although no upper neuron signs were observed clinically, it is not uncommon to see degeneration in the corticospinal tract in post-mortem examination. The question was what might have been the cause of increase in CK and amylase. Many participants thought that they were secondary to multiple organ failure due to prolonged hypoxic state at his last admission; other possibilities raised included acute myocardial infarction and acute bowel necrosis. Post-mortem examination revealed muscle atrophy in the facial, lingual, cervical, intercostal, and the upper limb girdle areas. The lungs were unremarkable except for old organized pneumonic foci in the right middle and lower lobes. Marked to moderate congestion was seen in many internal organs, however, no other gross abnormality was found. It was thought that respiratory palsy itself was the direct cause of his agonal event. In the spinal cord, the anterior horns showed various degree of neuronal loss and gliosis. No clear evidence of pyramidal tract degeneration was seen at the light microscope level. Lower brain stem motor neurons were markedly reduced. But no Bunina body was found. The substantia nigra showed moderate degree of neuronal loss and extraneuronal neuromelanins. The locus coeruleus showed similar but milder changes. The degree of nigral degeneration appeared to be well beyond those which could be seen in usual ALS patients. The question was whether or not this patient might have been in an early stage of the extended form of ALS.

Amyotrophic Lateral Sclerosis↗

[A patient with focal bi-parietal atrophy presenting motor clumsiness and cortical sensory loss].

We report a 73-year-old woman who presented progressive motor clumsiness, cortical sensory loss, and focal parietal lobe atrophy. She was well until one year prior to the present admission when she suffered from what appeared to be mild Fisher syndrome from which she showed excellent recovery. However, soon she noted a gradual onset of difficulty in hand movements and in the recognition of objects by hands. Neurologic examination revealed an alert and well oriented Japanese woman without dementia. Cranial nerves were unremarkable. Although, she did not have aphasia, apraxia, or agnosia, she showed marked clumsiness in skilled hand movements such as using chopsticks, hand writing, and buttoning. She had no motor weakness, ataxia, rigidity, or spasticity. Deep tendon reflexes were symmetrically diminished. Sensory examination revealed cortical sensory loss such as disturbances of two point discrimination, weight sensation, and stereotactic sensations. Her motor clumsiness appeared to be caused by her cortical sensory loss. MRI revealed marked focal atrophy in the bilateral parietal lobe, particularly in the postcentral gyrus and the adjacent association areas. Recently, neurodegenerative disorders with focal brain atrophy such as corticobasal degeneration, Pick's disease, and dementia of frontal lobe type have been reported, however, our patient does not fit to any of these known disorders nor clinical features are distinctly different from Alzheimer's disease. Our patient may be another example of progressive cerebral degeneration with emphasis on the parietal cortex.

Aged↗

[A 64-year-old woman with progressive gait disturbance and dementia for one year].

We report a 64-year-old Japanese woman who died one year after the onset of progressive gait disturbance and dementia. She noted a difficulty in holding a glass and hand tremor in June of 1996 when she was 63 years old. In July of 1996, she tended to lean toward left when she walked. She also noted truncal titubation. In November of 1996, she started to have visual hallucination and delusion in which she said "I see something is flying on the wall.", "Somebody has come into my room", and things like that. She was admitted to our service on November 22, 1996. On admission, she was alert and general physical examination was unremarkable. Neurologic examination revealed disturbance in recent memory. Hasegawa's dementia rating scale was 22/30. She showed vivid visual hallucination with colors in which she saw faces of dwarfs and angels, a space ship, and others. Higher cerebral functions were normal. She showed left oculomotor palsy which was a sequel of an aneurysm and subarachnoid hemorrhage nine years before. Otherwise cranial nerves were unremarkable. She showed ataxic gait, limb ataxia, truncal titubation, and postural hand tremor. She had no weakness and no muscle atrophy. Deep tendon reflexes were within normal limits. Plantar response was flexor. Sensation was intact. Laboratory examination was also unremarkable. Complete survey for occult malignancy was negative. CSF was under a normal pressure and cell count was 1/microliter, total protein 27 mg/dl, and sugar 68 mg/dl. Cranial CT scan was unremarkable. MRI was not obtained because of the presence of an aneurysm clip in the left internal carotid-posterior communication artery junction. She showed progressive deterioration in her mental function. By January 1997, she became unable to stand or walk with marked dementia. Repeated CSF exams and cranial CT scans were unremarkable. She suffered from several episodes of aspiration pneumonia. A trial of three days methylprednisolone pulse therapy was given starting on March 7, 1997, which was of no effect on her neurologic status. On March 28, 1997, she was intubated because of acute respiratory distress syndrome. In April 2, her body temperature rose to 38 degrees C. On April 9, 1997, her blood pressure dropped and resuscitation was unsuccessful. She was pronounced dead on the same day. The patient was discussed in a neurologic CPC and the chief discussant arrived at the conclusion that the patient had primary leptomeningeal lymphoma. Other possibilities entertained among the audience included brain stem encephalitis of unknown type, carcinomatous cerebellar degeneration plus limbic encephalitis, Creutzfeldt-Jakob disease, thalamic degeneration, and progressive multifocal leukoencephalopathy. Post-mortem examination revealed thickening and clouding of the leptomeninges; Gram-positive diplococci were found in the leptomeninges. This meningitis appeared to have been an complication in the terminal stage of her illness. Microscopic examination revealed astrocytosis in the midbrain tegmentum. Cerebral cortices showed only mild astrtocytosis. No cerebellar atrophy was seen and Purkinje cells were retained which excluded paraneoplastic cerebellar degeneration. Neuropathologic diagnosis was bacterial meningitis, however, the presence of brain stem encephalitis prior to the onset of bacterial meningitis could not be excluded. It is interesting to note that the diagnosis of the primary neurologic disease of this patient was not easy even after autopsy. As autopsy permission was obtained only for the brain, it was not clear whether or not this patient had an occult malignancy somewhere in her body, however, there was no evidence to indicate paraneoplastic degeneration of the central nervous system. As the patient did not have meningeal signs until one month before her death, it is difficult to ascribe her entire neurologic problems to her meningitis. Finally, her visual hallucination was vivid and colorful; we thought this might have been

Brain Stem↗

Mn SOD activity and protein in a patient with chromosome 6-linked autosomal recessive parkinsonism in comparison with Parkinson's disease and control.

We report Mn superoxide dismutase (SOD) protein and activity in a patient with familial autosomal recessive Lewy body-negative parkinsonism in comparison with patients with sporadic Parkinson's disease (PD) and controls. We recently proved linkage of this family with markers of chromosome 6 at 6q25.2-27, which included the Mn SOD gene. We used a novel polymorphic mutation at -9 position of the signal peptide of the Mn SOD precursor protein, which caused valine to alanine substitution. All the affected members of this family showed homozygosity for alanine, whereas nonaffected members, sporadic PD patients, and the control subjects studied showed either heterozygosity of alanine and valine or homozygosity of valine. The Mn SOD activity of this familial patient was the highest among the PD patients and the control subjects studied, and an abundant expression of Mn SOD was found in the substantia nigra. The molecular weight of Mn SOD protein by Western blotting of this patient was essentially similar to that of PD patients and the control subjects. High Mn SOD activity may constitute a genetic risk factor in this familial patient. The difference in the signal peptide sequence may affect the expression of Mn SOD within mitochondria; however, it is unlikely that loss of function type Mn SOD mutation is the cause of this familial parkinsonism. Mn SOD in sporadic PD patients was similar to that in controls.

Adult↗

[Clinical characteristics and linkage analysis of autosomal recessive form of juvenile parkinsonism(AR-JP)].

We present the clinical characteristics of autosomal recessive form of juvenile parkinsonism(AR-JP) (MIM 600116) and the result of the linkage analysis using 11 markers on the long arm of chromosome 6. We examined 25 patients of 13 Japanese AR-JP families. They showed female predominance, mean age at onset at 24.4 +/- 10.3 years, slow progression, good response to levodopa and frequent occurrence of wearing-off phenomenon and dopa-induced dyskinesia. Compared to Parkinson's disease(PD), the parkinsonian triad(tremor, rigidity and bradykinesia) were mild, but dystonic posture, postural instability and hyperreflexia were more prominent compared to PD. By the linkage analysis, we obtained a strong evidence for linkage of the AR-JP gene to a 17 cM region of chromosome 6q25.2-27 including the Mn-superoxide dismutase gene(SOD2) with a maximal cumulative multipoint lod score of 9.44 at 0.9 cM telomeric to D6S253.

Adolescent↗

Localization of a gene for an autosomal recessive form of juvenile Parkinsonism to chromosome 6q25.2-27.

An autosomal recessive form of juvenile Parkinsonism (AR-JP) (MIM 600116) is a levodopa-responsive Parkinsonism whose pathological finding is a highly selective degeneration of dopaminergic neurons in the zona compacta of the substantia nigra. By linkage analysis of diallelic polymorphism of the Mn-superoxide dismutase gene (SOD2), we found a family with AR-JP showing perfect segregation of the disease with the SOD2 locus. By extending the linkage analysis to 13 families with AR-JP, we discovered strong evidence for the localization of the AR-JP gene at chromosome 6q25.2-27, including the SOD2 locus, with the maximal cumulative pairwise LOD scores of 7.26 and 7.71 at D6S305 (theta = .03) and D6S253 (theta = .02), respectively. Observation of obligate recombination events, as well as multipoint linkage analysis, placed the AR-JP gene in a 17-cM interval between D6S437 and D6S264. Delineation of the AR-JP gene will be an important step toward our understanding of the molecular mechanism underlying selective degeneration of the nigral neurons.

Adolescent↗

[(Neurological CPC-59). A 65-year-old man with a history of gastric cancer who presented progressive loss of vision, memory loss and consciousness disturbance].

We report a 65-year-old man with progressive loss of vision and consciousness disturbance. The patient was well until his age of 63 when he was found to have a gastric cancer. He was treated by the tumor resection and chemotherapy; he was apparently well, but hepatic metastases were found in the next year (1996). In June, 1996, he noted an onset of blurred vision more on the left. He was admitted to the ophthalmology service of our hospital on July 14, 1996. His vision was 0.8 on the right and 0.15 on the left. He was treated with oral prednisolone with slight improvement. He was also found to have IgM kappa-type monoclonal gammopathy; Bence-Jones protein was positive and a bone marrow aspiration revealed that approximately 10% of bone marrow cells were atypical plasma cells. His vision had progressively got worse and he became blind by the end of October 1996. A chest X-ray and cranial CT scan revealed multiple abnormal nodular densities. In the middle of November 1996, he became confused, disoriented and agitated. His mental symptoms had progressively became worse, and a neurologic consultation was asked on December 10, 1996. Neurologic examination revealed that he was somnolent with decreased attention to his surroundings. He showed marked disorientation and memory loss. Higher cerebral functions appeared intact. He was able to recognize only light and dark. Pupils were moderately dilated with very sluggish light reflex remained. Vertical gaze was moderately restricted and horizontal nystagmus was noted upon left and right lateral gaze. The remaining of the neurologic examination were unremarkable. General physical examination revealed hepatosplenomegaly; the liver was palpable by 3 cm below the right costal margin. Laboratory examination revealed anemia (Hb10.1 g/dl) and thrombocytopenia (43,000/microliter). A cranial CT scan and MRI revealed a mass lesion in involving the chiasmatic and bilateral hypothalamic areas. The tumor showed intense homogeneous enhancement after Gd-DTPA infusion. The patient was treated with dexamethasone and radiation. After 9 Gray radiation, he showed deterioration in the sensorium; a cranial CT scan revealed a hydrocephalus of the right ventricle with the midline shift towards left. The radiation was discontinued. The subsequent clinical course was complicated by aspiration pneumonia and thrombocytopenia. He expired on January 4, 1997. The patient was discussed in a neurological CPC and the chief discussant arrived at the conclusion that the patient had systemic malignant lymphoma with metastasis to the brain judging from the characteristics of MRI and CT findings. Opinions were divided between malignant lymphoma and metastatic brain tumor. Post-mortem examination revealed plasmacytoid lymphocytic infiltration in the bone marrow. Immunologically, these cells were positive for IgM and kappa-type light chain. These plasmacytic infiltrations were seen in the lungs and lymph nodes. These findings were consistent with the diagnosis of Waldenström's macroglobulinemia. In the liver metastatic cancer tissues were seen; microscopic pictures were essentially similar to those of resected gastric cancer. No local recidive was noted in the stomach. In the central nervous system, a necrotic tissue was involving the hypothalamic area bilaterally; no clear neoplastic cells were found, however, lymphocytic and plasmacytic infiltrations were seen in the perivascular space. In the optic nerves, loss of myelin and axons were seen. These findings most likely mass formation from macroglobulinemia which underwent necrotic change after radiation. Mass formation in the brain is rare for Waldenström's macroglobulinemia, although it has been reported. The relation between gastric cancer and macroglobulinemia in this patient is unclear.

Adenocarcinoma↗

Structural dimorphism in the mitochondrial targeting sequence in the human manganese superoxide dismutase gene. A predictive evidence for conformational change to influence mitochondrial transport and a study of allelic association in Parkinson's disease.

Mitochondrial targeting sequence (MTS) has a common property to form an amphiphilic helical structure which is essential for its effective transport of mitochondrial protein. Natural polymorphism in human MTS which affects its mitochondrial transport ability has not been reported. Furthermore, no structural polymorphism for manganese superoxide dismutase (MnSOD) gene has been studied in human population. We here identify diallelic polymorphism (Ala-9Val) in the MTS of human MnSOD in a Japanese population. Calculation of a helix forming potential predicted the typical amphiphilic helical structure in -9Ala allele and its disruption in -9Val allele. We here suggest that this mutation may reflect functional polymorphism of mitochondrial transport of human MnSOD. An association study using this polymorphism showed significant allelic deviation for -9Ala allele (12.1% vs. 19.3%) in Parkinson's disease.

Aged↗

[A 52-year-old man with sensory aphasia and multiple intracranial masses].

We report a 52-year-old-man who developed aphasia, apraxia and agnosia. He was well until December of 1991 when he noted an onset of skin scaling in the extensor sides of his elbow joints; he was admitted to the dermatology service of our hospital and was diagnosed as having pemphigoid. Treatment with PDN 30 to 60 mg/day and azathioprine 50-100 mg was started. While in the hospital there was a insidious onset of right tinnitus and tingling sensation in his right leg in the middle of March, 1991. During next one week, his family noted that the patient responded incoherently in his speech once in a while. Neurological consult was requested on April 2, 1991. On neurologic examination, he was alert but incoherent in his speech. His spontaneous speech was reduced but it was fluent. However, he had a difficulty in understanding spoken as well as written language. Naming and repetition were also impaired, and he appeared to have Wernicke's aphasia. Ideational apraxia, ideomotor apraxia, constructional apraxia, left-right disorientation, finger agnosia, and body agnosia were noted as well, but he did not have dressing apraxia or spatial disorientation. Right homonymous hemianopsia was present, but any other cranial nerves were not disturbed. He had no weakness or ataxia; gait was normal. Deep reflexes were normal and symmetric. Sensations were intact. Complete blood counts and routine blood chemistries were normal. The lung was clear. Opening pressure at spinal tap of CSF was under a normal pressure; CSF contained 6 lymphocytes/microliters and 78mg/dl of protein; a cytological study showed no malignant cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Aphasia, Wernicke↗

Diverse mechanisms of control of aromatase gene expression.

The synthesis of estrogens from androgens is catalyzed by a microsomal cytochrome P450 termed aromatase (P450arom). The expression of this enzyme is highly regulated in both a developmental and cell-type specific fashion. We have chosen to examine the molecular basis of aromatase gene regulation by studying two models of aromatase expression: the Sebright bantam chicken and the R2C rat Leydig tumor cell line. In the first model, affected (Sebright) chickens express aromatase in many extragonadal tissues, while normal Leghorn chickens express aromatase only in the ovary and hypothalamus. Our studies have demonstrated that in normal chickens the site of transcription initiation is located approx. 147 nucleotides upstream of the initiator methionine. While Sebright animals also express aromatase mRNA initiated at an analogous initiation site in the ovary, a distinctive species of aromatase mRNA is also detected and is present in ovary and extragonadal tissues. This mRNA contains an identical coding sequence, but contains an alternatively spliced 5' noncoding exon that is derived from a distinctive promoter. The second model, the R2C Leydig tumor cell line, provides ample contrast. This cell line expresses high basal levels of aromatase (150-200 pmol/h/mg protein) that is suppressed with administration of 8 bromo cAMP or forskolin but the activity is not altered by glucocorticoids or epidermal growth factor treatment. Despite this distinctive pattern of regulation, at least three species of aromatase mRNA are detected in Northern blots, each of which is also detected in rat ovary. Primer extension and S1 nuclease assays indicate that both granulosa cells and R2C cells utilize a promoter that is located approx. 97 nucleotides upstream of the initiator methionine. These studies suggest that the "ovarian" promoter is evolutionarily conserved in both rats and chickens. These results further imply that the genetic mechanisms controlling the diversity of aromatase expression among tissues and among different species are likely to fall into two groups: those that employ distinctive promoters and alternative splicing and those that effect different patterns of regulation through a common ("ovarian") promoter.

Animals↗

Aromatase mRNA in the extragonadal tissues of chickens with the henny-feathering trait is derived from a distinctive promoter structure that contains a segment of a retroviral long terminal repeat. Functional organization of the Sebright, Leghorn, and Campine aromatase genes.

The henny-feathering trait is an autosomal dominant mutation that causes the expression of aromatase activity and accumulation of aromatase mRNA in extragonadal tissues of chickens. The current studies establish that the aromatase gene is not amplified and is organized similarly in control (Leghorn) and henny-feathered (Sebright and Campine) birds. Nucleotide sequence analysis of the nine coding exons of the aromatase gene reveals that the predicted amino acid sequence is identical in all three strains. We, therefore, characterized the genomic DNA segments flanking the coding segment of the Sebright, Leghorn, and Campine aromatase genes. The site of transcription initiation utilized in the ovary of all three strains is located approximately 147 nucleotides upstream of the initiator methionine. In addition to aromatase mRNA derived from this common ovarian promoter, another species of aromatase mRNA is present in Sebright and Campine ovary and is the only type detected in Sebright fibroblasts. cDNA copies of this second species of aromatase mRNA contain a unique 5' terminus, suggesting that a second promoter controls extragonadal aromatase expression in birds that carry the henny-feathering trait. Nucleotide sequence analysis of this 5' terminus indicates that this segment is derived from a retroviral long terminal repeat.

Amino Acid Sequence↗

Aromatase expression in extragonadal tissues of the Sebright chicken is controlled by a retroviral promoter.

These studies have clarified a number of issues regarding the genetic control of extragonadal aromatase expression in birds carrying the henny-feathering trait. The marked increased in extragonadal aromatase expression of a unique species of aromatase mRNA is apparently controlled by a retrovirus. We have not yet established whether this promoter is the consequence of a new retroviral insertion or is due to a mutation in a preexisting retrovirus. It is of interest in this regard that the chicken aromatase gene is located in a region of chromosome 1 known to be rich in retroviral insertions. Second, the relationship of the henny-feathering trait to normal and abnormal extragonadal aromatase expression in man remains to be determined. At one extreme, it is possible that a similar mechanism may underlie syndromes typified by increases in extraglandular aromatase expression. Even if the parallel proves to be less exact, the Sebright chicken provides important insight into how aromatase expression may be modulated differently in different tissues. Finally, the discovery that retroviral sequences appear to modulate the expression of aromatase in extragonadal tissues represents an unusual method by which the genetic control of genes can be altered. In the case of the henny-feathering trait, the alteration in the dimorphic feathering pattern was the principal clue to the altered regulation of extragonadal aromatase. This relation is in keeping with the other examples of altered gene expression caused by retroviruses that have also caused morphologic alterations such as changes in coat color or the appearance of neoplasms (for examples, see Refs. 14-16).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗